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Sample records for acanthamoeba astigmatism blepharitis

  1. Blepharitis

    MedlinePlus

    ... certain types of skin conditions such as acne rosacea . Anterior blepharitis affects the outside of the eyelid ... blepharitis at the same time in varying degrees. Rosacea blepharitis is associated with ocular rosacea , a condition ...

  2. Blepharitis.

    PubMed

    Bernardes, Taliana Freitas; Bonfioli, Adriana Alvim

    2010-05-01

    Blepharitis is a chronic inflammatory process of the eyelid margin. It is a common eye disorder throughout the world and can affect any age group. It may be associated with several systemic diseases, particularly rosacea and seborrheic dermatitis, and is related to other ocular conditions like dry eye, chalazion, conjunctivitis, and keratitis. Common symptoms associated with blepharitis are burning sensation, irritation, tearing, photophobia, blurred vision, and red eyes. Clinical examination reveals the presence of scurf, telangiectatic vascular changes of the eyelid margin, inspissated meibomian glands, conjuntival hyperemia, punctuate keratopathy, cornea vascularization, and ulceration. Patients with longstanding chronic blepharitis may present hypertrophy of the lid margin, scars, madarosis, trichiasis, and poliosis. Treatment of blepharitis is long and unsatisfactory. Long-term commitment to eyelid hygiene is essential. Other treatment options are discussed.

  3. Interventions for chronic blepharitis

    PubMed Central

    Lindsley, Kristina; Matsumura, Sueko; Hatef, Elham; Akpek, Esen K

    2012-01-01

    Background Blepharitis, an inflammatory condition associated with itchiness, redness, flaking, and crusting of the eyelids, is a common eye condition that affects both children and adults. It is common in all ethnic groups and across all ages. Although infrequent, blepharitis can lead to permanent alterations to the eyelid margin or vision loss from superficial keratopathy (abnormality of the cornea), corneal neovascularization, and ulceration. Most importantly, blepharitis frequently causes significant ocular symptoms such as burning sensation, irritation, tearing, and red eyes as well as visual problems such as photophobia and blurred vision. The exact etiopathogenesis is unknown, but suspected to be multifactorial, including chronic low-grade infections of the ocular surface with bacteria, infestations with certain parasites such as demodex, and inflammatory skin conditions such as atopy and seborrhea. Blepharitis can be categorized in several different ways. First, categorization is based on the length of disease process: acute or chronic blepharitis. Second, categorization is based on the anatomical location of disease: anterior, or front of the eye (e.g. staphylococcal and seborrheic blepharitis), and posterior, or back of the eye (e.g. meibomian gland dysfunction (MGD)). This review focuses on chronic blepharitis and stratifies anterior and posterior blepharitis. Objectives To examine the effectiveness of interventions in the treatment of chronic blepharitis. Search methods We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2012, Issue 1), MEDLINE (January 1950 to February 2012), EMBASE (January 1980 to February 2012), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We searched the reference lists of included studies for any

  4. Interventions for chronic blepharitis

    PubMed Central

    Lindsley, Kristina; Matsumura, Sueko; Hatef, Elham; Akpek, Esen K

    2012-01-01

    Background Blepharitis, an inflammatory condition associated with itchiness, redness, flaking, and crusting of the eyelids, is a common eye condition that affects both children and adults. It is common in all ethnic groups and across all ages. Although infrequent, blepharitis can lead to permanent alterations to the eyelid margin or vision loss from superficial keratopathy (abnormality of the cornea), corneal neovascularization, and ulceration. Most importantly, blepharitis frequently causes significant ocular symptoms such as burning sensation, irritation, tearing, and red eyes as well as visual problems such as photophobia and blurred vision. The exact etiopathogenesis is unknown, but suspected to be multifactorial, including chronic low-grade infections of the ocular surface with bacteria, infestations with certain parasites such as demodex, and inflammatory skin conditions such as atopy and seborrhea. Blepharitis can be categorized in several different ways. First, categorization is based on the length of disease process: acute or chronic blepharitis. Second, categorization is based on the anatomical location of disease: anterior, or front of the eye (e.g. staphylococcal and seborrheic blepharitis), and posterior, or back of the eye (e.g. meibomian gland dysfunction (MGD)). This review focuses on chronic blepharitis and stratifies anterior and posterior blepharitis. Objectives To examine the effectiveness of interventions in the treatment of chronic blepharitis. Search methods We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2012, Issue 1), MEDLINE (January 1950 to February 2012), EMBASE (January 1980 to February 2012), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We searched the reference lists of included studies for any

  5. Classification of chronic blepharitis.

    PubMed

    McCulley, J P; Dougherty, J M; Deneau, D G

    1982-10-01

    Since last thoroughly evaluated over three decades ago, the clinical spectrum of chronic blepharitis has changed. The relative prevalence of Staphylococcus aureus alone or in combination with seborrheic blepharitis has decreased. The relative prevalence has increased of seborrheic blepharitis with or without associated excess meibomian secretions (meibomian seborrhea) or inflammation (meibomitis). Primary meibomitis appears not to be a primarily infectious entity but to represent a facet of generalized sebaceous gland dysfunction and to be found in association with seborrheic dermatitis or acne rosacea. The keratoconjunctivitis found in association with primary meibomitis may be contributed to by the production of bacterial lypolytic exoenzymes that split neutral lipids, resulting in an increased level of free fatty acids in the tears. A frequent finding of keratoconjunctivitis sicca in this patient population, especially the S. aureus group (50%), is of note. Of particular importance is that these entities be recognized as chronic diseases requiring control and ones for which there is no "cure."

  6. [Calcinosis conjunctivae in chronic blepharitis].

    PubMed

    Auw-Hädrich, C; Reinhard, T

    2008-01-01

    We present a case of a 53-year-old female patient with chronic blepharitis and conjunctival overgrowth of the cornea. Histologically the conjunctival overgrowth contained foreign body granulomas around calcification focuses. This could have been promoted by the application of phosphate-containing eye drops and the presence of chemokines like TNF-alpha, which occur in chronic blepharitis. Thus, we recommend the application of phosphate-free eye drops in patients with chronic blepharitis.

  7. Blepharitis: Always Remember Demodex

    PubMed Central

    Bhandari, Vipul; Reddy, Jagadeesh K.

    2014-01-01

    Purpose: To determine the incidence and density of Demodex species on the eyelashes of subjects with normal eyelids, anterior blepharitis (AB), meibomian-gland dysfunction (MGD), and mixed blepharitis (MB). Materials and Methods: One hundred and fifty consecutive patients diagnosed with AB, MGD, and MB were recruited. An additional 50 individuals were recruited who were free of lid and margin disease to serve as a control group. All patients underwent a standard eye examination. Data on ocular symptomatology were gathered. Digital photography was performed of the lid margins. Lash sampling was performed by epilating the lashes and the lashes were checked for Demodex based on morphology using light microscopy. The total number of mites were tabulated for each eye. Comparison between the affected eyes and the control eyes was performed. Data were analyzed using the Chi-square test. Results: A total of 200 patients were included. Twenty percenth had AB, 40% had MGD, and 40% had MB. The incidence of Demodex infestation was 90% in cases of AB, 60% in MGD cases, and 90% in MB cases. The incidence of Demodex in control subjects was 18%. Conclusions: The incidence and density of Demodex infestation was highest in patients with AB and MB. Lid irritation and presence of cylindrical dandruff were indicative of a high-density infestation. These signs should alert the clinician to treat concomitant Demodex infestation. PMID:25371637

  8. Chronic blepharitis: a review.

    PubMed

    Smith, R E; Flowers, C W

    1995-07-01

    Although blepharitis is one of the most common ocular disorders encountered in clinical practice, it may constitute a diagnostic and therapeutic enigma. Attempts to classify this disorder are difficult because of the complex mechanisms underlying its pathogenesis. Clinical and laboratory investigations have clearly established bacteria and meibomian gland abnormalities as major etiologic determinants. In addition, changes in tear film dynamics and underlying dermatologic abnormalities appear to contribute to pathogenesis. The clinical manifestations primarily occur along the lid margin, and the predominant symptoms are itching and burning. Currently there is no cure for this condition. In the case of staphylococcal blepharitis, for example, there is no long-term cure because patients are likely susceptible to the causative organism(s), and thus become reinfected. Therapy is aimed then at bringing the disease process under control. A therapeutic regimen consisting of lid hygiene, topical or systemic antibiotics, and tear replacement seems to be most effective in alleviating symptoms and maintaining disease control but requires prolonged treatment.

  9. Discoid lupus erythematosus presenting as unilateral blepharitis.

    PubMed

    Au, Leon

    2006-01-01

    A 39-year-old man presented with a 4-month history of unilateral blepharitis that did not respond to conventional treatment. Punch biopsy confirmed the diagnosis of discoid lupus erythematosus. Unilateral blepharitis as the only presenting sign of discoid lupus erythematosus is uncommon but should be considered in the differential diagnosis in patients with asymmetric blepharitis.

  10. Pathogenic role of Demodex mites in blepharitis

    PubMed Central

    Liu, Jingbo; Sheha, Hosam; Tseng, Scheffer C.G.

    2010-01-01

    Purpose of review To summarize the key literature and our research experience regarding Demodex infestation as a potential cause of ocular inflammatory diseases with a special emphasis on Demodex blepharitis. Recent findings Two distinct Demodex species have been confirmed as a cause of blepharitis: Demodex folliculorum can cause anterior blepharitis associated with disorders of eyelashes, and D. brevis can cause posterior blepharitis with meibomian gland dysfunction and keratoconjunctivitis. Tea tree oil treatments with either 50% lid scrubs or 5% lid massages are effective in eradicating mites and reducing ocular surface inflammation. Summary Demodex blepharitis is a common but overlooked external eye disease. The pathogenesis of Demodex blepharitis in eliciting ocular surface inflammation has been further clarified. The modified eyelash sampling and counting method makes it easier and more accurate to diagnose Demodex infestation. Tea tree oil shows promising potential to treat Demodex blepharitis by reducing Demodex counts with additional antibacterial, antifungal, and anti-inflammatory actions. PMID:20689407

  11. Meibomian gland dysfunction in chronic blepharitis.

    PubMed

    Mathers, W D; Shields, W J; Sachdev, M S; Petroll, W M; Jester, J V

    1991-07-01

    We examined 57 patients with symptoms of chronic blepharitis using meibomian gland expression, meibography, tear osmolarity, and the Schirmer's test. We also performed meibography on 20 normal patients free of chronic blepharitis. We found that 42 blepharitis patients (74%) had evidence of meibomian gland loss, whereas only four of 20 normal patients (20%) had any gland dropout. We performed cluster analysis on the data from the patients with blepharitis and found that these patients tended to fall into distinct groups with clinically relevant characteristics. We also found that tear osmolarity correlated positively with gland dropout (+0.413) and negatively with excreta volume (-0.499). This study demonstrates that an objective analysis of meibomian gland function may be used to assess chronic blepharitis and define subsets of blepharitis with measurable differences. It also supports the significance of meibomian gland dysfunction on tear osmolarity and the evaporative state of the eye.

  12. [Progress of study on the demodex blepharitis].

    PubMed

    Zhang, X Y; Sun, X G

    2016-04-11

    Demodex blepharitis is an infectious ocular disease which is common, but always to be neglected. There were a few related reports about this disease in China. The pathogenic mechanism of demodex blepharitis is not clear at present. Literatures held different ideas about its diagnosis, therapeutic methods and curative effect. This review will summarize the new development of demodex blepharitis in order to provide references for its basic and clinical researches.(Chin J Ophthalmol, 2016, 52: 315-320).

  13. [Progress of study on the demodex blepharitis].

    PubMed

    Zhang, X Y; Sun, X G

    2016-04-11

    Demodex blepharitis is an infectious ocular disease which is common, but always to be neglected. There were a few related reports about this disease in China. The pathogenic mechanism of demodex blepharitis is not clear at present. Literatures held different ideas about its diagnosis, therapeutic methods and curative effect. This review will summarize the new development of demodex blepharitis in order to provide references for its basic and clinical researches.(Chin J Ophthalmol, 2016, 52: 315-320). PMID:27094071

  14. Acanthamoeba meningoencephalitis

    PubMed Central

    Chandra, S. R.; Adwani, Sikandar; Mahadevan, Anitha

    2014-01-01

    Report of a case of young immunocompetent male adult with autopsy proven acanthamoeba meningoencephalitis. The patient presented with a protracted febrile illness of 3 months duration with features of meningoencephalitis, this was followed by rapid deterioration while on anti tuberculous therapy and steroids and ended fatally. His magnetic resonance imaging showed features of hemorrhagic meningoencephalitis and magnetic resonance spectroscopy showed choline peak. Autopsy revealed necrotizing meningoencephalitis and intraocular colonization due to acanthamoeba. PMID:24753675

  15. Acanthamoeba keratitis.

    PubMed

    Pogson, C

    1993-01-01

    1. Acanthamoeba keratitis is an uncommon but increasingly prevalent infection with the potential to cause severe ocular damage. Acanthamoeba is a nonflagellated free-living amoeba that is ubiquitous in the environment. The most common type is A castellani, but A polyphagia, A rhysodes, A culbertson, and A hatchetti have been isolated from infected eyes. 2. Clinical features include foreign body sensation, blurred vision, tearing, and photophobia. There is minimal pain in the early stages of infection, but severe pain is a manifestation of the advanced stages of the disease. 3. The incidence of Acanthamoeba keratitis appears to be decreasing because of increased awareness, but education emphasizing proper lens sterilization is essential and should be carried out when contact lenses are first dispensed. PMID:8158668

  16. Astigmatism in cataract surgery.

    PubMed Central

    Luntz, M. H.; Livingston, D. G.

    1977-01-01

    We report on our investigation into astigmatism in 40 eyes following a corneal cataract incision closed with a continuous 10/0 nylon monofilament suture (Ethilon). Immediately after surgery there was astigmatism caused by the nylon suture (suture-induced astigmatism), its severity depending on the tightness of the suture. It ranged from 1 to 10-5 dioptres, the mean value 4-09 dioptres with a standard deviation of +/-2-5. Removing the nylon suture eliminated this astigmatism and within a few weeks the corneal astigmatism correction in 48% of eyes returned to the preoperative level. In 80% of eyes the difference between the final postoperative corneal astigmatism (4 months after removing the continuous suture) and the preoperative astigmatism was 0-75 dioptres or less and the maximum change was 1-5 dioptres. In 40% of eyes the axis of the cylinder changed from a horizontal to an oblique axis but did not change from a with- to against-the-rule axis. The degree of astigmatism remained constant while the suture was in place and in 50% of eyes was equal to or less than 3 dioptres. The mean of the spherical equivalents was 11-31 dioptres with a standard deviation of +/-1-25. A spectacle correction 14 days after operation prescribed either as the mean spherical equivalent (11-50 dioptres) or according to the patient's refraction will give satisfactory vision until the suture is removed 4 months after operation. The degree of astigmatism following a corneal section and continuous nylon suture compares very favourably with astigmatism following other suturing techniques for cataract. Images PMID:326304

  17. [Blepharitis--rare in systemic lupus erythematosus].

    PubMed

    Gyl, Fekete; Anna-Adrien, Csiszár; Oanţă, A; Irimie, M; Edit, Fekete Júlia

    2008-01-01

    Chronic lupus erythematosus often appear on the face, ears, and scalp. In exchange eyelids involvement as a chronic blepharitis is rare. We describe six cases of discoid lupus erythematosus with lesions on the face and ears who have eyelids involvement, too. Blepharitis is a rare involvement of the chronic lupus erythematosus and in case that is isolated, the diagnosis is belated and can lead to complications. The involvement of the lower eyelids is more frequently especially theirs lateral third.

  18. Treatment of blepharitis: recent clinical trials.

    PubMed

    Pflugfelder, Stephen C; Karpecki, Paul M; Perez, Victor L

    2014-10-01

    Blepharitis is a chronic inflammatory disease of the eyelids that is frequently encountered in clinical practice. The etiology of the disorder is complex and not fully understood, but the general consensus is that bacteria and inflammation contribute to the pathology. Blepharitis can be classified into anterior blepharitis, involving the anterior lid margin and eyelashes, and posterior blepharitis, characterized by dysfunction of the meibomian glands. Long-term management of symptoms may include daily eyelid cleansing routines and the use of therapeutic agents that reduce infection and inflammation. A cure is not possible in most cases, and subjective symptoms may persist even when a clinical assessment of signs indicates that the condition has improved. There are no established guidelines regarding therapeutic regimens, but recent clinical trials have shown that antibiotics and topical corticosteroids can produce significant improvement in signs and symptoms of blepharitis. Fixed combinations of a topical antibiotic and a corticosteroid offer an effective and convenient treatment modality that addresses both infectious and inflammatory components of the disease. Further clinical trials are needed to determine optimal therapies for managing blepharitis.

  19. Treatment of blepharitis: recent clinical trials.

    PubMed

    Pflugfelder, Stephen C; Karpecki, Paul M; Perez, Victor L

    2014-10-01

    Blepharitis is a chronic inflammatory disease of the eyelids that is frequently encountered in clinical practice. The etiology of the disorder is complex and not fully understood, but the general consensus is that bacteria and inflammation contribute to the pathology. Blepharitis can be classified into anterior blepharitis, involving the anterior lid margin and eyelashes, and posterior blepharitis, characterized by dysfunction of the meibomian glands. Long-term management of symptoms may include daily eyelid cleansing routines and the use of therapeutic agents that reduce infection and inflammation. A cure is not possible in most cases, and subjective symptoms may persist even when a clinical assessment of signs indicates that the condition has improved. There are no established guidelines regarding therapeutic regimens, but recent clinical trials have shown that antibiotics and topical corticosteroids can produce significant improvement in signs and symptoms of blepharitis. Fixed combinations of a topical antibiotic and a corticosteroid offer an effective and convenient treatment modality that addresses both infectious and inflammatory components of the disease. Further clinical trials are needed to determine optimal therapies for managing blepharitis. PMID:25284773

  20. Blepharitis

    MedlinePlus

    ... the oil (meibomian) glands in the eyelid Acne rosacea Scalp dandruff (seborrheic dermatitis) Allergy Who's At Risk ... have scalp dandruff (seborrheic dermatitis), dry skin, acne rosacea, contact allergies, diabetes, poor hygiene, or those sensitive ...

  1. Blepharitis

    MedlinePlus

    ... Your health care provider might recommend using baby shampoo or special cleansers. Using an antibiotic ointment in ... solution of warm water and no-tears baby shampoo along your eyelid, where the lash meets the ...

  2. Astigmatism following cataract surgery.

    PubMed

    Reading, V M

    1984-02-01

    The changes in corneal curvature were determined at regular intervals over a one-year period following intracapsular cataract extraction by microsurgical techniques. During the first postoperative month photokeratometric measurements showed rapid changes in astigmatism associated with large changes in the direction of the axis. Thereafter astigmatism against-the-rule predominated. Data from the small group of patients who underwent surgery in which the technique of phacoemulsification was used show that the smaller changes in corneal curvature are attributable to the smaller incision size and reduced number of sutures. With patients who underwent intracapsular extraction a comparison has been made between the effects of large and small section sizes, and a procedure is outlined whereby surgically induced astigmatism may be minimised.

  3. [Chronic blepharitis. Pathogenesis, clinical features, and therapy].

    PubMed

    Auw-Haedrich, C; Reinhard, T

    2007-09-01

    Chronic blepharitis is one of the most common diseases of the eyelids, but surprisingly, it is not often recognized. Frequently, a skin disease such as seborrheic dermatitis, atopic dermatitis, or acne rosacea is the underlying cause of chronic blepharitis. Bacterial pathological lipase, cholesterylesterase production, and bacterial lipopolysaccharides are pathogenetically relevant. Only rarely do genuine bacterial infections play a role. Collarettes occur at the base of the eye lashes, and the Meibomian glands show either abundant fluid secretion or inspissated secretion with obstruction of the orifices. Chronic blepharitis can include sequelae including dry eye and corneal and lid contour changes. The basic treatment comprises attendance of the underlying dermatological disease and lid hygiene. In addition, preservative-free tear film substitutes, antibiotics, immunomodulatory agents, or even surgical intervention may become necessary.

  4. Astigmatism and diagnostic procedures.

    PubMed

    Visnjić, Mirna Belovari; Zrinsćak, Ognjen; Barisić, Freja; Iveković, Renata; Laus, Katia Novak; Mandić, Zdravko

    2012-06-01

    Astigmatism represents an inability of the cornea and lens to provide a sharp image onto the retina. Correcting astigmatic errors, whether congenital, contact lens induced or surgically induced, is now an integral part of modern cataract and refractive procedures. Development of modern technology has enabled accurate diagnosis and perfect opportunities for correction; however, while cataract and keratorefractive surgery have come a long way in the last decade, the treatment and diagnosis of astigmatism continue to challenge ophthalmologists. There are several diagnostic procedures and tools available today, some standard and some contemporary that include keratometry, corneal topography, apparatus using wavefront or Scheimpflug analysis like Orbscan, Pentacam, Wavescan, etc. With the introduction of several new diagnostic tools, measurements of astigmatism have become less of an issue, but in some cases it is still difficult to obtain consistent results. What remains still unanswered is the question of the best diagnostic tool on the market. Further research is needed to evaluate both tools as well as their clinical application for optimal use. PMID:23115957

  5. Infant astigmatism and meridional amblyopia.

    PubMed

    Gwiazda, J; Mohindra, I; Brill, S; Held, R

    1985-01-01

    The orientation preferences of 70 infants aged 7 to 53 weeks with significant astigmatism [1.0 or more diopters (D)] were measured using a preferential looking procedure with paired gratings. The preference data show the consequences of the blurring effects of astigmatism when these are not compensatable by accommodation. Data from infant astigmats tested with optical correction look like those of nonastigmats. We have found no evidence for the development of meridional amblyopia during the first year of life. PMID:4072007

  6. [Rosacea-like demodicidosis and chronic blepharitis].

    PubMed

    Anane, S; Mokni, M; Beltaief, O

    2011-01-01

    Demodicidosis is a parasitic skin disease caused by the follicle mites Demodex sp. In this article, we present a case of rosacea-like demodicidosis, discuss the clinical features of Demodex infestation in man and review their diagnosis and therapeutic modalities. A 37-year-old woman presented in our department with chronic blepharitis present for one year. On physical examination, the patient presented blepharitis and papulovesicles with fine scaling limited to the face. There was no telangectasia. The patient did not report flushing episodes or any kind of photosensitivity. A diagnosis of rosacea-like demodicidosis and Demodex blepharitis was based on the presence of numerous Demodex folliculorum in the eyelashes and scrapings of skin lesions. The patient was put on topic and oral metronidazole for 2 months and on yellow mercury ointment for 15 days. The course involved disappearance of the facial mites and complete remission without recurrence. Screening for Demodex sp is essential to establish the correct diagnosis and ensure suitable treatment. PMID:21276458

  7. [Rosacea-like demodicidosis and chronic blepharitis].

    PubMed

    Anane, S; Mokni, M; Beltaief, O

    2011-01-01

    Demodicidosis is a parasitic skin disease caused by the follicle mites Demodex sp. In this article, we present a case of rosacea-like demodicidosis, discuss the clinical features of Demodex infestation in man and review their diagnosis and therapeutic modalities. A 37-year-old woman presented in our department with chronic blepharitis present for one year. On physical examination, the patient presented blepharitis and papulovesicles with fine scaling limited to the face. There was no telangectasia. The patient did not report flushing episodes or any kind of photosensitivity. A diagnosis of rosacea-like demodicidosis and Demodex blepharitis was based on the presence of numerous Demodex folliculorum in the eyelashes and scrapings of skin lesions. The patient was put on topic and oral metronidazole for 2 months and on yellow mercury ointment for 15 days. The course involved disappearance of the facial mites and complete remission without recurrence. Screening for Demodex sp is essential to establish the correct diagnosis and ensure suitable treatment.

  8. Amblyopia in Astigmatic Infants and Toddlers

    PubMed Central

    Dobson, Velma; Harvey, Erin M.; Clifford-Donaldson, Candice E.; Green, Tina K.; Miller, Joseph M.

    2010-01-01

    Purpose To determine if reduced astigmatism-corrected acuity for vertical (V) and/or horizontal (H) gratings and/or meridional amblyopia (MA) are present prior to age three years in children who have with-the-rule astigmatism. Methods Subjects were 448 children, 6 months through 2 years of age with no known ocular abnormalities other than with-the-rule astigmatism, who were recruited through Women, Infants and Children clinics on the Tohono O’odham reservation. Children were classified as non-astigmats (≤ 2.00 D) or astigmats (> 2.00 D) based on right eye (RE) non-cycloplegic autorefraction measurements (Welch Allyn SureSight). RE astigmatism-corrected grating acuity for V and H stimuli was measured using the Teller Acuity Card procedure while children wore cross-cylinder lenses to correct their astigmatism or plano lenses if they had no astigmatism. Results Astigmatism-corrected acuity for both V and H gratings was significantly poorer in the astigmats than in the non-astigmats, and the reduction in acuity for astigmats was present for children in all three age groups examined (6 months to <1 year, 1 to <2 years, 2 to <3 years). There was no significant difference in V-H grating acuity (no evidence of MA) for the astigmatic group as a whole, or when data were analyzed for each age group. Conclusions Even in the youngest age group, astigmats tested with astigmatism correction showed reduced acuity for both V and H gratings, which suggests that astigmatism is having a negative influence on visual development. We found no evidence of orientation-related differences in astigmatism-corrected grating acuity, indicating either that MA does not develop prior to age 3 years, or that most of the astigmatic children had a type of astigmatism, i.e., hyperopic, that has proven to be less likely than myopic or mixed astigmatism to result in MA. PMID:20351602

  9. Giant papillary conjunctivitis and meibomian gland dysfunction blepharitis.

    PubMed

    Martin, N F; Rubinfeld, R S; Malley, J D; Manzitti, V

    1992-07-01

    In this prospective pilot study we saw 42 consecutive giant papillary conjunctivitis (GPC) patients (80 eyes), all of whom were found to have some meibomian gland dysfunction blepharitis. Severity of GPC at presentation correlated with severity of meibomian gland dysfunction blepharitis (Kendall's tau b averaged 0.246 across the adjusted statistical analyses). Thirty-two patients (63 eyes) were refit after treating meibomian gland dysfunction blepharitis. Twenty-eight of these patients (55 eyes; 87%) continue to wear contact lenses, maintaining an improvement in GPC (mean follow-up 21 months; range 11-36 months). We hypothesize that meibomian gland dysfunction blepharitis may play a role in the pathogenesis of GPC and suggest that a large, controlled, multi-observer study be performed to further investigate this possible association.

  10. [Painless acanthamoeba keratitis].

    PubMed

    Stemberger, K; Dick, B; Kramann, C; Thieme, H; Weber, A; Petry, F; Pfeiffer, N

    2007-05-01

    A 37-year-old contact lens wearer was treated for herpes simplex keratitis. After an initial improvement the keratitis became much worse. An annular infiltrate gave rise to the suspicion of acanthamoeba keratitis even though the patient was not in pain. This diagnosis was confirmed by histological and microbiological examination of the corneal disc after keratoplasty. Acanthamoeba keratitis should be considered even in the absence of pain, especially when the patients are contact lens wearers.

  11. Immunity to Acanthamoeba.

    PubMed

    Ferrante, A

    1991-01-01

    Human serum contains antibodies, mainly of the IgM and IgG isotypes, to pathogenic species of Acanthamoeba. This, as well as the capacity of these amebas to activate complement via the alternative pathway, may be a first-line defense against acanthamoeba infections in humans. Both antibody and complement appear to be important in promoting recognition of these amebas by phagocytic cells such as neutrophils. However, killing of amebas by neutrophils is dependent on lymphokine/monokine priming of the neutrophil. This priming augments the respiratory-burst activity and release of lysosomal enzymes of neutrophils in their response to the ameba. The products of the oxygen-dependent respiratory burst appear to be of prime importance in the killing of this free-living ameba. Antibodies also may prevent tissue invasion by Acanthamoeba by inhibiting its adherence, phagocytic activity, and migration and by neutralizing cytopathogenic amebic agents. Studies on experimental Acanthamoeba infections in mice showed marked species and strain specificity with regard to induction of protection with amebic antigens. Immune compromise or, alternatively, invasion at unique body sites in healthy individuals may form the basis for human infection with Acanthamoeba. PMID:2047675

  12. Ecology of Acanthamoeba.

    PubMed

    De Jonckheere, J F

    1991-01-01

    Acanthamoeba is a free-living ameba that is present in all types of environments throughout the world. The recent increase in cases of keratitis, especially in relation to an increase in the use of contact lenses, is probably due to the omnipresence of the organism as a result of the pronounced resistance of its cysts to disinfection and desiccation. The temperature of the eye is lower than that of the rest of the human body. Therefore, the presence of Acanthamoeba strains that grow at lower temperatures may also contribute to infection, thereby increasing the number of possibly infectious amebas. Recent evidence, however, indicates that perhaps only a limited number of species cause ocular disease. Delineation of the exact species of Acanthamoeba that cause keratitis is a prerequisite for the study of the ecology of the keratitis-producing amebas. PMID:2047667

  13. Detection of Acanthamoeba on the ocular surface in a Spanish population using the Schirmer strip test: pathogenic potential, molecular classification and evaluation of the sensitivity to chlorhexidine and voriconazole of the isolated Acanthamoeba strains.

    PubMed

    Rocha-Cabrera, Pedro; Reyes-Batlle, María; Martín-Navarro, Carmen María; Dorta-Gorrín, Alexis; López-Arencibia, Atteneri; Sifaoui, Ines; Martínez-Carretero, Enrique; Piñero, José E; Martín-Barrera, Fernando; Valladares, Basilio; Lorenzo-Morales, Jacob

    2015-08-01

    Pathogenic strains of Acanthamoeba are causative agents of a sight-threatening infection of the cornea known as Acanthamoeba keratitis, which is often associated with the misuse of contact lenses. However, there is still a question remaining to be answered, which is whether these micro-organisms are present on the ocular surface of healthy individuals. Therefore, the aim of this study was to determine the presence of Acanthamoeba on the ocular surface in healthy patients and also in those with other ocular surface infections. Sterile Schirmer test strips were used to collect samples from a group of patients who attended an ophthalmology consultation at the Hospital del Norte, Icod de los Vinos, Tenerife, Canary Islands. Most of the patients (46 individuals, 79.31  %) presented ocular surface pathologies such as blepharitis or conjunctivitis; the rest did not present any pathology. None of the patients included in the study wore contact lenses. The collected samples were cultured in 2  % non-nutrient agar plates and positive plates were then cultured in axenic conditions for further analyses. Molecular analysis classified all isolated strains as belonging to Acanthamoeba genotype tbl4, and osmotolerance and thermotolerance assays revealed that all strains were potentially pathogenic. Furthermore, all strains were assayed for sensitivity against voriconazole and chlorhexidine. Assays showed that both drugs were active against the tested strains. In conclusion, the Schirmer strip test is proposed as an effective tool for the detection of Acanthamoeba on the ocular surface.

  14. Detection of Acanthamoeba on the ocular surface in a Spanish population using the Schirmer strip test: pathogenic potential, molecular classification and evaluation of the sensitivity to chlorhexidine and voriconazole of the isolated Acanthamoeba strains.

    PubMed

    Rocha-Cabrera, Pedro; Reyes-Batlle, María; Martín-Navarro, Carmen María; Dorta-Gorrín, Alexis; López-Arencibia, Atteneri; Sifaoui, Ines; Martínez-Carretero, Enrique; Piñero, José E; Martín-Barrera, Fernando; Valladares, Basilio; Lorenzo-Morales, Jacob

    2015-08-01

    Pathogenic strains of Acanthamoeba are causative agents of a sight-threatening infection of the cornea known as Acanthamoeba keratitis, which is often associated with the misuse of contact lenses. However, there is still a question remaining to be answered, which is whether these micro-organisms are present on the ocular surface of healthy individuals. Therefore, the aim of this study was to determine the presence of Acanthamoeba on the ocular surface in healthy patients and also in those with other ocular surface infections. Sterile Schirmer test strips were used to collect samples from a group of patients who attended an ophthalmology consultation at the Hospital del Norte, Icod de los Vinos, Tenerife, Canary Islands. Most of the patients (46 individuals, 79.31  %) presented ocular surface pathologies such as blepharitis or conjunctivitis; the rest did not present any pathology. None of the patients included in the study wore contact lenses. The collected samples were cultured in 2  % non-nutrient agar plates and positive plates were then cultured in axenic conditions for further analyses. Molecular analysis classified all isolated strains as belonging to Acanthamoeba genotype tbl4, and osmotolerance and thermotolerance assays revealed that all strains were potentially pathogenic. Furthermore, all strains were assayed for sensitivity against voriconazole and chlorhexidine. Assays showed that both drugs were active against the tested strains. In conclusion, the Schirmer strip test is proposed as an effective tool for the detection of Acanthamoeba on the ocular surface. PMID:26293786

  15. [Chronic blepharitis: which role for Demodex folliculorum? A case report].

    PubMed

    Martinaud, C; Gaillard, T; Pons, S; Fournier, B; Brisou, P

    2009-01-01

    We present a 73-year-old woman presented to our hospital with a 2 years history of eyes itching. The ophthalmological testing was normal. Physical examination revealed blepharitis and lesions acnea-like on mouth, nose and chest. Biological testing revealed no abnormalities. Histologic study and direct immunofluorescence on a cutaneous biopsy were no contributive. The research of an allergic origine was practised by cutaneous and serological tests and negative. An examination of eyelashes was performed and yielded Demodex. Demodex folliculorum is a mite that is the most common permanent ectoparasite of humans, which is thought to be linked to blepharitis and allergic blepharoconjunctivis with rosacea, although much controversy persists. Recent studies demonstrate a high frequence of chronic blepharitis when Demodex are abundant. Several molecules can be used to treat this infestation. Parasiticide as oral ivermectine may be useful when the infestation is important.

  16. [Chronic blepharitis: which role for Demodex folliculorum? A case report].

    PubMed

    Martinaud, C; Gaillard, T; Pons, S; Fournier, B; Brisou, P

    2009-01-01

    We present a 73-year-old woman presented to our hospital with a 2 years history of eyes itching. The ophthalmological testing was normal. Physical examination revealed blepharitis and lesions acnea-like on mouth, nose and chest. Biological testing revealed no abnormalities. Histologic study and direct immunofluorescence on a cutaneous biopsy were no contributive. The research of an allergic origine was practised by cutaneous and serological tests and negative. An examination of eyelashes was performed and yielded Demodex. Demodex folliculorum is a mite that is the most common permanent ectoparasite of humans, which is thought to be linked to blepharitis and allergic blepharoconjunctivis with rosacea, although much controversy persists. Recent studies demonstrate a high frequence of chronic blepharitis when Demodex are abundant. Several molecules can be used to treat this infestation. Parasiticide as oral ivermectine may be useful when the infestation is important. PMID:19939774

  17. Pathogenesis of Acanthamoeba Keratitis

    PubMed Central

    Panjwani, Noorjahan

    2010-01-01

    Acanthamoeba keratitis (AK) is a serious infection of the cornea. At present, diagnosis of the disease is not straightforward and treatment is very demanding. While contact lens wear is the leading risk factor for AK, Acanthamoeba parasites are increasingly recognized as an important cause of keratitis in non-contact lens wearers. The first critical step in the pathogenesis of infection is the adhesion of the microbe to the surface of the host tissues. Acanthamoebae express a major virulence protein, the mannose-binding protein (MBP), which mediates the adhesion of amoebae to the surface of the cornea. The MBP is a transmembrane protein with characteristics of a typical cell surface receptor. Subsequent to the MBP-mediated adhesion to host cells, the amoebae produce a contact-dependent metalloproteinase and several contact-independent serine proteinases. These proteinases work in concert to produce a potent cytopathic effect (CPE) involving killing of the host cells, degradation of epithelial basement membrane and underlying stromal matrix, and penetration into the deeper layers of the cornea. In the hamster animal model, oral immunization with the recombinant MBP protects against AK, and this protection is associated with an increased level of anti-MBP IgA in tears of protected animals. Normal human tear fluid contains IgA antibodies against Acanthamoeba MBP that is likely to provide protection by inhibiting the adhesion of parasites to host cells. Indeed, in in vitro CPE assays, even a low concentration of tears (10 [MU]μL of undiluted tears per milliliter of media) almost completely inhibits Acanthamoeba-induced CPE. In addition to adherence-inhibiting, IgA-mediated protection, human tears also contain IgA-independent factors that provide protection against Acanthamoeba-induced CPE by inhibiting the activity of cytotoxic proteinases. Characterization of the CPE-inhibitory factors of human tears should lead to a better understanding of the mechanism by which the

  18. Biology and pathogenesis of Acanthamoeba.

    PubMed

    Siddiqui, Ruqaiyyah; Khan, Naveed Ahmed

    2012-01-01

    Acanthamoeba is a free-living protist pathogen, capable of causing a blinding keratitis and fatal granulomatous encephalitis. The factors that contribute to Acanthamoeba infections include parasite biology, genetic diversity, environmental spread and host susceptibility, and are highlighted together with potential therapeutic and preventative measures. The use of Acanthamoeba in the study of cellular differentiation mechanisms, motility and phagocytosis, bacterial pathogenesis and evolutionary processes makes it an attractive model organism. There is a significant emphasis on Acanthamoeba as a Trojan horse of other microbes including viral, bacterial, protists and yeast pathogens.

  19. Biology and pathogenesis of Acanthamoeba

    PubMed Central

    2012-01-01

    Acanthamoeba is a free-living protist pathogen, capable of causing a blinding keratitis and fatal granulomatous encephalitis. The factors that contribute to Acanthamoeba infections include parasite biology, genetic diversity, environmental spread and host susceptibility, and are highlighted together with potential therapeutic and preventative measures. The use of Acanthamoeba in the study of cellular differentiation mechanisms, motility and phagocytosis, bacterial pathogenesis and evolutionary processes makes it an attractive model organism. There is a significant emphasis on Acanthamoeba as a Trojan horse of other microbes including viral, bacterial, protists and yeast pathogens. PMID:22229971

  20. Campylobacter-Acanthamoeba interactions.

    PubMed

    Vieira, Ana; Seddon, Alan M; Karlyshev, Andrey V

    2015-05-01

    Campylobacter jejuni is a foodborne pathogen recognized as the major cause of human bacterial enteritis. Undercooked poultry products and contaminated water are considered as the most important sources of infection. Some studies suggest transmission and survival of this bacterial pathogen may be assisted by the free-living protozoa Acanthamoeba. The latter is known to play the role of a host for various pathogenic bacteria, protecting them from harsh environmental conditions. Importantly, there is a similarity between the mechanisms of bacterial survival within amoebae and macrophages, making the former a convenient tool for the investigation of the survival of pathogenic bacteria in the environment. However, the molecular mechanisms involved in the interaction between Campylobacter and Acanthamoeba are not well understood. Whilst some studies suggest the ability of C. jejuni to survive within the protozoa, the other reports support an extracellular mode of survival only. In this review, we focus on the studies investigating the interaction between Campylobacter and Acanthamoeba, address some reasons for the contradictory results, and discuss possible implications of these results for epidemiology. Additionally, as the molecular mechanisms involved remain unknown, we also suggest possible factors that may be involved in this process. Deciphering the molecular mechanisms of pathogen-protozoa interaction will assist in a better understanding of Campylobacter lifestyle and in the development of novel antibacterial drugs.

  1. Astigmatism

    MedlinePlus

    Katz M, Kruger PB. The human eye as an optical system. In: Tasman W, Jaeger EA, eds. Duane's Ophthalmology . 2013 ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2013:chap 33. Kramarevsky N, Hardten ...

  2. Astigmatism among institutionalized and noninstitutionalized mentally retarded.

    PubMed

    Courtney, G R

    1977-06-01

    Astigmatism was measured retinoscopically for 709 subjects residing in an institution for the mentally retarded and for 56 noninstitutionalized mentally retarded subjects at a community training center. About 60% of the subjects were between 15 and 45 years old. Compared to an intellectually normal sample of young men, astigmatism in the mentally retarded was greater in frequency and degree. For subjects with greater degrees of mental retardation, the prevalence of high astigmastism was significantly greater for whites than for nonwhites. There was no difference in astigmatism between institutionalized retardates and those living in a community setting, a finding that implies that the institutional environment was not the cause of the astigmatic differences between retarded and normal subjects.

  3. A design of PAL with astigmatism

    NASA Astrophysics Data System (ADS)

    Wei, Yefei; Xiang, Huazhong; Zhu, Tianfeng; Chen, Jiabi

    2015-08-01

    Progressive addition lens (PAL) is designed for those who suffer from myopia and presbyopia to have a clear vision from a far distance to a nearby distance. Additionally there are many people that also suffer from astigmatism and need to be corrected. The cylinder power can't be simply added to the diopter of the PAL directly, because the diopter of the PAL needs to be changed smoothly. A methods has been proposed in this article to solve the problem, the freeform surface height of a PAL without astigmatism and the cylindrical lens surface height for the correction of astigmatism are calculated separately. The both two surface heights were added together, then the final surface is produced and shown with the both properties of PALs and cylindrical lenses used to correct the astigmatism.

  4. Use of azithromycin ophthalmic solution in the treatment of chronic mixed anterior blepharitis.

    PubMed

    John, Thomas; Shah, Ami A

    2008-01-01

    We tested the efficacy of azithromycin ophthalmic solution for the treatment of chronic mixed anterior blepharitis. The findings suggest that patients with chronic mixed anterior blepharitis can be more effectively treated with azithromycin ophthalmic solution than erythromycin ophthalmic ointment. Patients treated with azithromycin ophthalmic solution show an extraordinary clinical response with shorter treatment duration.

  5. Comparison of incidence of Demodex folliculorum on the eyelash follicule in normal people and blepharitis patients.

    PubMed

    Türk, Meral; Oztürk, Ilgin; Sener, Asli Gamze; Küçükbay, Safiye; Afşar, Ilhan; Maden, Ahmet

    2007-01-01

    Demodex folliculorum has been incriminated in the development of blepharitis although much controversy persist. Some authors suggest that Demodex is a direct pathogen in chronic palpebral conditions while others consider the saprophyte to be innocuous to skin. We conducted a prospective study of eyelashes in 48 patients with blepharitis (totally 96 eyes) and 48 healthy persons (totally 96 eyes), searching for Demodex folliculorum and chronic blepharitis. Microscopy in immersion oil after storage in a moist chamber was performed. It is determined Demodex follicullorum in 11 of 37 (29.72%) patients with blepharitis, in one of 11 (9.09%) patient with blepharoconjunctivitis and in 2 of 48 (4.16%) persons in healthy control group. Staphylococcus aureus was cultivated in five patients and D. folliculorum was found two of them. The incidence of Demodex folliculorum was high in patients with blepharitis compared with normal controls. Incidence was high in males. Anti-Demodex treatment is indicated when the parasite is found.

  6. Astigmatism and the development of myopia in children.

    PubMed

    Gwiazda, J; Grice, K; Held, R; McLellan, J; Thorn, F

    2000-01-01

    While it is now established that astigmatism is more prevalent in infants and young children than in the adult population, little is known about the functional significance of this astigmatism, especially its role, if any, in emmetropization and the development of myopia. Manifest refractions (mean of 16 per subject) were obtained from 245 subjects starting in the first year, with 6-23 years of regular follow-up. Results showed that infantile astigmatism is associated with increased astigmatism and myopia during the school years. Two possible mechanisms underlying this association are discussed: (1) infantile astigmatism disrupts focusing mechanisms; and (2) ocular growth induces astigmatism and myopia.

  7. Improved astigmatic focus error detection method

    NASA Technical Reports Server (NTRS)

    Bernacki, Bruce E.

    1992-01-01

    All easy-to-implement focus- and track-error detection methods presently used in magneto-optical (MO) disk drives using pre-grooved media suffer from a side effect known as feedthrough. Feedthrough is the unwanted focus error signal (FES) produced when the optical head is seeking a new track, and light refracted from the pre-grooved disk produces an erroneous FES. Some focus and track-error detection methods are more resistant to feedthrough, but tend to be complicated and/or difficult to keep in alignment as a result of environmental insults. The astigmatic focus/push-pull tracking method is an elegant, easy-to-align focus- and track-error detection method. Unfortunately, it is also highly susceptible to feedthrough when astigmatism is present, with the worst effects caused by astigmatism oriented such that the tangential and sagittal foci are at 45 deg to the track direction. This disclosure outlines a method to nearly completely eliminate the worst-case form of feedthrough due to astigmatism oriented 45 deg to the track direction. Feedthrough due to other primary aberrations is not improved, but performance is identical to the unimproved astigmatic method.

  8. Tubular astigmatism-tunable fluidic lens.

    PubMed

    Kopp, Daniel; Zappe, Hans

    2016-06-15

    We demonstrate a new means to fabricate three-dimensional liquid lenses which may be tuned in focal length and astigmatism. Using actuation by electrowetting-on-dielectrics, astigmatism in arbitrary directions may be tuned independently, with almost no cross talk between orthogonal orientations. The lens is based on electrodes structured on planar polyimide foils and subsequently rolled, enabling high-resolution patterning of complex electrodes along the azimuthal and radial directions of the lens. Based on a design established through fluidic and optical simulations, the astigmatism tuning is experimentally verified by a change of the corresponding Zernike coefficients measured using a Shack-Hartmann wavefront sensor. It was seen that the back focal length can be tuned by 5 mm and 0° and 45° astigmatism by 3 μm through application of voltages in the range of 50  Vrms. It was observed that the cross talk with other aberrations is very low, suggesting a novel means for astigmatism control in imaging systems.

  9. Blepharitis in the United States 2009: a survey-based perspective on prevalence and treatment.

    PubMed

    Lemp, Michael A; Nichols, Kelly K

    2009-04-01

    ABSTRACT Like dry eye disease 15 years ago, blepharitis today is a poorly defined condition about which there is considerable misunderstanding. For a variety of reasons, there is little good data on either the prevalence of blepharitis or how eyecare practitioners currently treat it. The work reported herein consists of two recent studies: a telephone survey of a representative sample of the adult US population (n = 5,000) whose purpose was to discover the frequency of common ocular surface symptoms associated with blepharitis; and a study that queried a selected group of ophthalmologists (n = 120) and a similarly selected group of optometrists (n = 84) about the frequency of blepharitis in their practices, the existence comorbid conditions, and their management strategies. This data suggests that blepharitis symptoms are very common in the US population, with younger individuals reporting more, and more frequent, symptoms than older people, contrary to clinical dogma. Ophthalmologists and optometrists report that blepharitis is commonly seen in clinical practice in 37% and 47% of their patients, respectively, and it is widely agreed that meibomian gland dysfunction (MGD) is the most common cause of evaporative dry eye disease. In addition, management paradigms are shifting away from more traditional management with antibiotic ointment and warm compress therapy to prescription therapy for anterior and posterior blepharitis.

  10. Dry eye, blepharitis and chronic eye irritation: divide and conquer.

    PubMed

    Gilbard, J P

    1999-01-01

    Dry eye and posterior blepharitis are the two most common causes for chronic eye irritation. Dry eye is caused by loss of water from the tear film resulting from either decreased tear production or increased tear film evaporation. The resultant increase in tear film osmolarity causes the changes on the eye surface responsible for the symptoms of dry eye. Posterior blepharitis causes eye irritation from inflammation, and leads to the development of meibomian gland dysfunction. The patient history is a powerful tool in narrowing the differential diagnosis of chronic eye irritation or even establishing the diagnosis. The exam adds power to the history, and sorts out the mechanisms causing dry eye symptoms. The primary goal of dry eye treatment is to lower elevated tear film osmolarity. This can be achieved with TheraTears treatment, either with or without punctal plugs. The primary goal of meibomitis treatment is to reduce inflammation. This can be achieved by hot compresses and lid massage and, when necessary, systemic treatment with low dose doxycycline. By determining the cause or causes of chronic eye irritation, effective treatments can be employed.

  11. Acanthamoeba castellanii STAT protein.

    PubMed

    Kicinska, Anna; Leluk, Jacek; Jarmuszkiewicz, Wieslawa

    2014-01-01

    STAT (signal transducers and activators of transcription) proteins are one of the important mediators of phosphotyrosine-regulated signaling in metazoan cells. We described the presence of STAT protein in a unicellular, free-living amoebae with a simple life cycle, Acanthamoeba castellanii. A. castellanii is the only, studied to date, Amoebozoan that does not belong to Mycetozoa but possesses STATs. A sequence of the A. castellanii STAT protein includes domains similar to those of the Dictyostelium STAT proteins: a coiled coil (characteristic for Dictyostelium STAT coiled coil), a STAT DNA-binding domain and a Src-homology domain. The search for protein sequences homologous to A. castellanii STAT revealed 17 additional sequences from lower eukaryotes. Interestingly, all of these sequences come from Amoebozoa organisms that belong to either Mycetozoa (slime molds) or Centramoebida. We showed that there are four separated clades within the slime mold STAT proteins. The A. castellanii STAT protein branches next to a group of STATc proteins from Mycetozoa. We also demonstrate that Amoebozoa form a distinct monophyletic lineage within the STAT protein world that is well separated from the other groups. PMID:25338074

  12. Acanthamoeba everywhere: high diversity of Acanthamoeba in soils.

    PubMed

    Geisen, Stefan; Fiore-Donno, Anna Maria; Walochnik, Julia; Bonkowski, Michael

    2014-09-01

    Acanthamoeba is a very abundant genus of soil protists with fundamental importance in nutrient cycling, but several strains can also act as human pathogens. The systematics of the genus is still unclear: currently 18 small-subunit (SSU or 18S) ribosomal RNA sequence types (T1-T18) are recognized, which sometimes contain several different morphotypes; on the other hand, some morphological identical strains belong to different sequence types, sometimes appearing in paraphyletic positions. In this study, we cultivated 65 Acanthamoeba clones from soil samples collected under grassland at three separate locations in the Netherlands, in Sardinia and at high altitude mountains in Tibet. We obtained 24 distinct partial sequences, which predominantly grouped within sequence type T4 followed by T2, T13, T16 and "OX-1" (in the T2/T6 clade). Our sequences were 98-99% similar, but none was identical to already known Acanthamoeba sequences. The community composition of Acanthamoeba strains differed between locations, T4 being the dominant sequence type in Sardinia and Tibet, but represented only half of the clones from soils in the Netherlands. The other half of clones from the Dutch soils was made up by T2, T16 and "OX-1", while T13 was only found in Sardinia and Tibet. None of the sequences was identical between localities. Several T4 clones from all three localities and all T13 clones grew at 37 °C while one T4 clone was highly cytopathogenic. PMID:24951165

  13. Acanthamoeba everywhere: high diversity of Acanthamoeba in soils.

    PubMed

    Geisen, Stefan; Fiore-Donno, Anna Maria; Walochnik, Julia; Bonkowski, Michael

    2014-09-01

    Acanthamoeba is a very abundant genus of soil protists with fundamental importance in nutrient cycling, but several strains can also act as human pathogens. The systematics of the genus is still unclear: currently 18 small-subunit (SSU or 18S) ribosomal RNA sequence types (T1-T18) are recognized, which sometimes contain several different morphotypes; on the other hand, some morphological identical strains belong to different sequence types, sometimes appearing in paraphyletic positions. In this study, we cultivated 65 Acanthamoeba clones from soil samples collected under grassland at three separate locations in the Netherlands, in Sardinia and at high altitude mountains in Tibet. We obtained 24 distinct partial sequences, which predominantly grouped within sequence type T4 followed by T2, T13, T16 and "OX-1" (in the T2/T6 clade). Our sequences were 98-99% similar, but none was identical to already known Acanthamoeba sequences. The community composition of Acanthamoeba strains differed between locations, T4 being the dominant sequence type in Sardinia and Tibet, but represented only half of the clones from soils in the Netherlands. The other half of clones from the Dutch soils was made up by T2, T16 and "OX-1", while T13 was only found in Sardinia and Tibet. None of the sequences was identical between localities. Several T4 clones from all three localities and all T13 clones grew at 37 °C while one T4 clone was highly cytopathogenic.

  14. Optical advantages of astigmatic aberration corrected heliostats

    NASA Astrophysics Data System (ADS)

    van Rooyen, De Wet; Schöttl, Peter; Bern, Gregor; Heimsath, Anna; Nitz, Peter

    2016-05-01

    Astigmatic aberration corrected heliostats adapt their shape in dependence of the incidence angle of the sun on the heliostat. Simulations show that this optical correction leads to a higher concentration ratio at the target and thus in a decrease in required receiver aperture in particular for smaller heliostat fields.

  15. Photochemotherapeutic strategy against Acanthamoeba infections.

    PubMed

    Aqeel, Yousuf; Siddiqui, Ruqaiyyah; Anwar, Ayaz; Shah, Muhammad Raza; Khoja, Shahrukh; Khan, Naveed Ahmed

    2015-01-01

    Acanthamoeba is a protist pathogen that can cause serious human infections, including blinding keratitis and a granulomatous amoebic encephalitis that almost always results in death. The current treatment for these infections includes a mixture of drugs, and even then, a recurrence can occur. Photochemotherapy has shown promise in the treatment of Acanthamoeba infections; however, the selective targeting of pathogenic Acanthamoeba has remained a major concern. The mannose-binding protein is an important adhesin expressed on the surface membranes of pathogenic Acanthamoeba organisms. To specifically target Acanthamoeba, the overall aim of this study was to synthesize a photosensitizing compound (porphyrin) conjugated with mannose and test its efficacy in vitro. The synthesis of mannose-conjugated porphyrin was achieved by mixing benzaldehyde and pyrrole, yielding tetraphenylporphyrin. Tetraphenylporphyrin was then converted into mono-nitrophenylporphyrin by selectively nitrating the para position of the phenyl rings, as confirmed by nuclear magnetic resonance (NMR) spectroscopy. The mono-nitrophenylporphyrin was reduced to mono-aminophenylporphyrin in the presence of tin dichloride and confirmed by a peak at m/z 629. Finally, mono-aminoporphyrin was conjugated with mannose, resulting in the formation of an imine bond. Mannose-conjugated porphyrin was confirmed through spectroscopic analysis and showed that it absorbed light of wavelengths ranging from 425 to 475 nm. To determine the antiacanthamoebic effects of the derived product, amoebae were incubated with mannose-conjugated porphyrin for 1 h and washed 3 times to remove extracellular compound. Next, the amoebae were exposed to light of the appropriate wavelength for 1 h. The results revealed that mannose-conjugated porphyrin produced potent trophicidal effects and blocked excystation. In contrast, Acanthamoeba castellanii incubated with mannose alone and porphyrin alone did not exhibit an antiamoebic effect

  16. Photochemotherapeutic Strategy against Acanthamoeba Infections

    PubMed Central

    Aqeel, Yousuf; Siddiqui, Ruqaiyyah; Anwar, Ayaz; Shah, Muhammad Raza; Khoja, Shahrukh

    2015-01-01

    Acanthamoeba is a protist pathogen that can cause serious human infections, including blinding keratitis and a granulomatous amoebic encephalitis that almost always results in death. The current treatment for these infections includes a mixture of drugs, and even then, a recurrence can occur. Photochemotherapy has shown promise in the treatment of Acanthamoeba infections; however, the selective targeting of pathogenic Acanthamoeba has remained a major concern. The mannose-binding protein is an important adhesin expressed on the surface membranes of pathogenic Acanthamoeba organisms. To specifically target Acanthamoeba, the overall aim of this study was to synthesize a photosensitizing compound (porphyrin) conjugated with mannose and test its efficacy in vitro. The synthesis of mannose-conjugated porphyrin was achieved by mixing benzaldehyde and pyrrole, yielding tetraphenylporphyrin. Tetraphenylporphyrin was then converted into mono-nitrophenylporphyrin by selectively nitrating the para position of the phenyl rings, as confirmed by nuclear magnetic resonance (NMR) spectroscopy. The mono-nitrophenylporphyrin was reduced to mono-aminophenylporphyrin in the presence of tin dichloride and confirmed by a peak at m/z 629. Finally, mono-aminoporphyrin was conjugated with mannose, resulting in the formation of an imine bond. Mannose-conjugated porphyrin was confirmed through spectroscopic analysis and showed that it absorbed light of wavelengths ranging from 425 to 475 nm. To determine the antiacanthamoebic effects of the derived product, amoebae were incubated with mannose-conjugated porphyrin for 1 h and washed 3 times to remove extracellular compound. Next, the amoebae were exposed to light of the appropriate wavelength for 1 h. The results revealed that mannose-conjugated porphyrin produced potent trophicidal effects and blocked excystation. In contrast, Acanthamoeba castellanii incubated with mannose alone and porphyrin alone did not exhibit an antiamoebic effect

  17. Bacillus oleronius and Demodex mite infestation in patients with chronic blepharitis.

    PubMed

    Szkaradkiewicz, A; Chudzicka-Strugała, I; Karpiński, T M; Goślińska-Pawłowska, O; Tułecka, T; Chudzicki, W; Szkaradkiewicz, A K; Zaba, R

    2012-10-01

    To better recognize the pathogenicity of ocular Demodex mites, we analysed Bacillus oleronius infection in patients with Demodex-related chronic blepharitis. The studies were conducted on 68 adult patients, in whom ophthalmological and parasitological tests permitted the distinction of a group of 38 patients with a diagnosis of Demodex-related chronic blepharitis (group 1, including a subgroup 1a with moderate blepharitis and a subgroup 1b with severe blepharitis) and a group of 30 healthy individuals (group 2). In every person studied six eyelashes were epilated from each eye and the number of Demodex per eyelash was scored. In parallel, bacterial culture and isolation allowed their phenotypic and molecular identification. The drug sensitivity of the isolates was tested using E-tests. Intensity of Demodex infestation showed no significant differences between subgroups 1a and 1b. From the epilated eyelashes 23 bacterial isolates were obtained, identified as being B. oleronius. All the studied strains were sensitive to ciprofloxacin, doxycycline and gentamicin. The Demodex mite represents an independent aetiopathogenetic factor in blepharitis. In parallel, the parasite may act as a carrier of B. oleronius bacteria, which most probably function as a co-pathogen in the development of severe forms of blepharitis.

  18. Comparative analysis of the tear protein expression in blepharitis patients using two-dimensional electrophoresis.

    PubMed

    Koo, Bon-Suk; Lee, Do-Yeon; Ha, Hyo-Shin; Kim, Jae-Chan; Kim, Chan-Wha

    2005-01-01

    Change in the expression of body fluid proteins is caused by many diseases or environmental disturbances. The changes in tear proteins are also associated with various pathological eye conditions. Especially, chronic blepharitis is one of the most common conditions seen in the ophthalmologist's office. However, there are no specific clinical diagnostic tests for blepharitis, and it is difficult to treat effectively. Therefore, the aim of this study was to screen prognostic or diagnostic marker tear proteins for blepharitis and investigate pathogenesis of this disease using proteomics techniques. The tear proteins expressed in patients suffering from blepharitis (patient, n=19) and healthy volunteers (control, n=27) were analyzed using the two-dimensional electrophoresis (2-DE) technique. The differentially expressed proteins in patients were identified with ESI-Q-TOF (electrospray-quadrupole-time-of-flight) mass spectrometry and confirmed with western blotting. Nine proteins in patient were down regulated about 50% compared to those of the control: serum albumin precursor, alpha-1 antitrypsin, lacritin precursor, lysozyme, Ig-kappa chain VIII, prolactin inducible protein (PIP/GCDFP-15), cystatin-SA III, pyruvate kinase, and an unnamed protein. The use of the two-dimensional eletrophoretic technique could give more insight into the disease-related protein expression changes in tear fluids. Our findings reveal that the composition of tear proteins in blepharitis patients is different from that of healthy subjects and may provide further insights into the pathogenesis of blepharitis.

  19. Two cases of tinea ciliaris with blepharitis due to Microsporum audouinii and Trichophyton verrucosum and review of the literature.

    PubMed

    Sahin, Gulay Ozel; Dadaci, Zeynep; Ozer, Turkan Toka

    2014-09-01

    Dermatophytes are rarely taken into account among the causes of blepharitis. In our report, we describe a 69-year-old man and a 40-year-old woman with chronic blepharitis for 10 years and 4 years respectively, in whom we examined the scales and pulled eyelashes on direct microscopy and isolated Microsporum audouinii and Trichophyton verrrucosum in the culture. We emphasise that dermatophytes may play a role in the etiopathogenesis of chronic blepharitis. In chronic, treatment resistance blepharitis fungal infections may be considered as possible cause.

  20. Two cases of tinea ciliaris with blepharitis due to Microsporum audouinii and Trichophyton verrucosum and review of the literature.

    PubMed

    Sahin, Gulay Ozel; Dadaci, Zeynep; Ozer, Turkan Toka

    2014-09-01

    Dermatophytes are rarely taken into account among the causes of blepharitis. In our report, we describe a 69-year-old man and a 40-year-old woman with chronic blepharitis for 10 years and 4 years respectively, in whom we examined the scales and pulled eyelashes on direct microscopy and isolated Microsporum audouinii and Trichophyton verrrucosum in the culture. We emphasise that dermatophytes may play a role in the etiopathogenesis of chronic blepharitis. In chronic, treatment resistance blepharitis fungal infections may be considered as possible cause. PMID:24724801

  1. Effects of posterior corneal astigmatism on the accuracy of AcrySof toric intraocular lens astigmatism correction

    PubMed Central

    Zhang, Bin; Ma, Jing-Xue; Liu, Dan-Yan; Guo, Cong-Rong; Du, Ying-Hua; Guo, Xiu-Jin; Cui, Yue-Xian

    2016-01-01

    AIM To evaluate the effects of posterior corneal surface measurements on the accuracy of total estimated corneal astigmatism. METHODS Fifty-seven patients with toric intraocular lens (IOL) implantation and posterior corneal astigmatism exceeding 0.5 diopter were enrolled in this retrospective study. The keratometric astigmatism (KA) and total corneal astigmatism (TA) were measured using a Pentacam rotating Scheimpflug camera to assess the outcomes of AcrySof IOL implantation. Toric IOLs were evaluated in 26 eyes using KA measurements and in 31 eyes using TA measurements. Preoperative corneal astigmatism and postoperative refractive astigmatism were recorded for statistical analysis. The cylindrical power of toric IOLs was estimated in all eyes. RESULTS In all cases, the difference of toric IOL astigmatism magnitude between KA and TA measurements for the estimation of preoperative corneal astigmatism was statistically significant. Of a total of 57 cases, the 50.88% decreased from Tn to Tn-1, and 10.53% decreased from Tn to Tn-2. In all cases, 5.26% increased from Tn to Tn+1. The mean postoperative astigmatism within the TA group was significantly lower than that in the KA group. CONCLUSION The accuracy of total corneal astigmatism calculations and the efficacy of toric IOL correction can be enhanced by measuring both the anterior and posterior corneal surfaces using a Pentacam rotating Scheimpflug camera. PMID:27672591

  2. Corneal topography in the study of astigmatic excimer laser ablation

    NASA Astrophysics Data System (ADS)

    McDonnell, Peter J.

    1992-08-01

    Corneal astigmatism, both naturally occurring and iatrogenically induced, is a commonly encountered problem. Examination of corneal topography with instruments that digitize reflected ring images and calculate corneal geometry suggests that corneal astigmatism often deviates from spherocylindrical optics; the observed topography may be highly asymmetrical about the center of the pupil. Currently used incisional procedures are limited in terms of predictability of surgical outcome. The 193 nm excimer laser can be used to alter anterior corneal curvature and flatten the cornea to correct myopia. For correction of astigmatism, a slit-opening in the laser delivery system can be used to selectively flatten the steep meridian. Early results using this procedure for correction of iatrogenically induced high corneal astigmatism are promising. A nationwide multicenter clinical trial is now underway in the United States to evaluate this technique for the correction of naturally occurring astigmatism and compound myopic astigmatism.

  3. On multisoliton solutions of the constant astigmatism equation

    NASA Astrophysics Data System (ADS)

    Hlaváč, Adam

    2015-09-01

    We introduce an algebraic formula producing infinitely many exact solutions of the constant astigmatism equation {z}{yy}+{(1/z)}{xx}+2=0 from a given seed. A construction of corresponding surfaces of constant astigmatism is then a matter of routine. As a special case, we consider multisoliton solutions of the constant astigmatism equation defined as counterparts of famous multisoliton solutions of the sine-Gordon equation. A few particular examples are surveyed as well.

  4. Axially astigmatic surfaces: different types and their properties

    NASA Astrophysics Data System (ADS)

    Malacara-Doblado, Daniel; Malacara-Hernandez, Daniel; Garcia-Marquez, Jorge L.

    1996-12-01

    Axially astigmatic surfaces have different curvatures in orthogonal diameters. Toroidal and spherocylindrical optical surfaces are two mathematically different special cases of axially astigmatic surfaces as noted by Menchaca and Malacara (1986), but they are almost identical in the vicinity of the optical axis. The different between these two surfaces increases when the distance to the optical axis increases. We study the general properties of astigmatic surfaces and some special interesting cases.

  5. Acanthamoeba Migration in an Electric Field

    PubMed Central

    Rudell, Jolene Chang; Gao, Jing; Sun, Yuxin; Sun, Yaohui; Chodosh, James; Schwab, Ivan; Zhao, Min

    2013-01-01

    Purpose. We investigated the in vitro response of Acanthamoeba trophozoites to electric fields (EFs). Methods. Acanthamoeba castellanii were exposed to varying strengths of an EF. During EF exposure, cell migration was monitored using an inverted microscope equipped with a CCD camera and the SimplePCI 5.3 imaging system to capture time-lapse images. The migration of A. castellanii trophozoites was analyzed and quantified with ImageJ software. For analysis of cell migration in a three-dimensional culture system, Acanthamoeba trophozoites were cultured in agar, exposed to an EF, digitally video recorded, and analyzed at various Z focal planes. Results. Acanthamoeba trophozoites move at random in the absence of an EF, but move directionally in response to an EF. Directedness in the absence of an EF is 0.08 ± 0.01, while in 1200 mV/mm EF, directedness is significantly higher at −0.65 ± 0.01 (P < 0.001). We find that the trophozoite migration response is voltage-dependent, with higher directionality with higher voltage application. Acanthamoeba move directionally in a three-dimensional (3D) agar system as well when exposed to an EF. Conclusions. Acanthamoeba trophozoites move directionally in response to an EF in a two-dimensional and 3D culture system. Acanthamoeba trophozoite migration is also voltage-dependent, with increased directionality with increasing voltage. This may provide new treatment modalities for Acanthamoeba keratitis. PMID:23716626

  6. Astigmatism in Monkeys with Experimentally Induced Myopia or Hyperopia

    PubMed Central

    KEE, CHEA-SU; HUNG, LI-FANG; QIAO-GRIDER, YING; RAMAMIRTHAM, RAMKUMAR; SMITH, EARL L.

    2006-01-01

    Purpose Astigmatism is the most common ametropia found in humans and is often associated with large spherical ametropias. However, little is known about the etiology of astigmatism or the reason(s) for the association between spherical and astigmatic refractive errors. This study examines the frequency and characteristics of astigmatism in infant monkeys that developed axial ametropias as a result of altered early visual experience. Methods Data were obtained from 112 rhesus monkeys that experienced a variety of lens-rearing regimens that were intended to alter the normal course of emmetropization. These visual manipulations included form deprivation (n = 13); optically imposed defocus (n = 48); and continuous ambient lighting with (n = 6) or without optically imposed defocus (n = 6). In addition, data from 19 control monkeys and 39 infants reared with an optically imposed astigmatism were used for comparison purposes. The lens-rearing period started at approximately 3 weeks of age and ended by 4 to 5 months of age. Refractive development for all monkeys was assessed periodically throughout the treatment and subsequent recovery periods by retinoscopy, keratometry, and A-scan ultrasonography. Results In contrast to control monkeys, the monkeys that had experimentally induced axial ametropias frequently developed significant amounts of astigmatism (mean refractive astigmatism = 0.37 ± 0.33 D [control] vs. 1.24 ± 0.81 D [treated]; two-sample t-test, p < 0.0001), especially when their eyes exhibited relative hyperopic shifts in refractive error. The astigmatism was corneal in origin (Pearson’s r; p < 0.001 for total astigmatism and the JO and J45 components), and the axes of the astigmatism were typically oblique and bilaterally mirror symmetric. Interestingly, the astigmatism was not permanent; the majority of the monkeys exhibited substantial reductions in the amount of astigmatism at or near the end of the lens-rearing procedures. Conclusions In infant monkeys

  7. Discoid lupus erythematosus of the eyelids associated with staphylococcal blepharitis and Meibomian gland dysfunction.

    PubMed

    Ena, P; Pinna, A; Carta, F

    2006-01-01

    Lower eyelid involvement occurs in 6% of patients with discoid lupus erythematosus (DLE). Eyelid lesions are rarely the initial manifestation of DLE. We describe a 25-year-old woman presenting with discoid lesions of the lower eyelids, staphylococcal blepharitis and Meibomian gland dysfunction, who later developed a discoid lesion on the chin. Histopathological and immunofluorescence studies of a biopsy specimen from this lesion established the diagnosis of DLE. We are unaware of any previously reported cases of DLE presenting with discoid eyelid lesions associated with staphylococcal blepharitis and Meibomian gland dysfunction. DLE should be considered as a differential diagnosis in chronic blepharitis that persists despite usual medical management and eyelid hygiene. Misdiagnosis may lead to eyelid margin deformities, necessitate a complicated full-thickness biopsy, and delay diagnosis of systemic lupus.

  8. Ocular rosacea: an underdiagnosed cause of relapsing conjunctivitis-blepharitis in the elderly.

    PubMed

    De Marchi, Sergio Umberto; Cecchin, Emanuela; De Marchi, Sergio

    2014-09-19

    Red eye and relapsing conjunctivitis-blepharitis are among the most common ocular disease in elderly patients. In these cases the search for causes is difficult and frustrating. We report the case of a 79-year-old woman with a long history of red eye and relapsing conjunctivitis-blepharitis caused by ocular rosacea. In this patient the proper diagnosis was performed after 10 years of ocular disease, and repeated evaluations by general practitioners and clinical specialists, only after the appearance of facial signs of erythematotelangiectatic rosacea. Adequate therapy with oral doxycycline led to the improvement of the clinical picture that previously had shown a poor response to several topical treatments. The possibility of ocular rosacea should be considered in evaluating an elderly patient with persistent red eye and relapsing conjunctivitis-blepharitis. Making the proper diagnosis is crucial because ocular rosacea does not respond as expected to topical therapy and may lead to severe corneal involvement.

  9. Ocular rosacea: an underdiagnosed cause of relapsing conjunctivitis-blepharitis in the elderly

    PubMed Central

    De Marchi, Sergio Umberto; Cecchin, Emanuela; De Marchi, Sergio

    2014-01-01

    Red eye and relapsing conjunctivitis-blepharitis are among the most common ocular disease in elderly patients. In these cases the search for causes is difficult and frustrating. We report the case of a 79-year-old woman with a long history of red eye and relapsing conjunctivitis-blepharitis caused by ocular rosacea. In this patient the proper diagnosis was performed after 10 years of ocular disease, and repeated evaluations by general practitioners and clinical specialists, only after the appearance of facial signs of erythematotelangiectatic rosacea. Adequate therapy with oral doxycycline led to the improvement of the clinical picture that previously had shown a poor response to several topical treatments. The possibility of ocular rosacea should be considered in evaluating an elderly patient with persistent red eye and relapsing conjunctivitis-blepharitis. Making the proper diagnosis is crucial because ocular rosacea does not respond as expected to topical therapy and may lead to severe corneal involvement. PMID:25239991

  10. Ocular rosacea: an underdiagnosed cause of relapsing conjunctivitis-blepharitis in the elderly.

    PubMed

    De Marchi, Sergio Umberto; Cecchin, Emanuela; De Marchi, Sergio

    2014-01-01

    Red eye and relapsing conjunctivitis-blepharitis are among the most common ocular disease in elderly patients. In these cases the search for causes is difficult and frustrating. We report the case of a 79-year-old woman with a long history of red eye and relapsing conjunctivitis-blepharitis caused by ocular rosacea. In this patient the proper diagnosis was performed after 10 years of ocular disease, and repeated evaluations by general practitioners and clinical specialists, only after the appearance of facial signs of erythematotelangiectatic rosacea. Adequate therapy with oral doxycycline led to the improvement of the clinical picture that previously had shown a poor response to several topical treatments. The possibility of ocular rosacea should be considered in evaluating an elderly patient with persistent red eye and relapsing conjunctivitis-blepharitis. Making the proper diagnosis is crucial because ocular rosacea does not respond as expected to topical therapy and may lead to severe corneal involvement. PMID:25239991

  11. Effect of suture material on postoperative astigmatism.

    PubMed

    Gimbel, H V; Raanan, M G; DeLuca, M

    1992-01-01

    Two hundred patients were enrolled in a randomized, prospective clinical trial comparing the use of 10-0 nylon, 10-0 polypropylene (Prolene), 11-0 polyester (Mersilene), and 10-0 polyethylene (Novafil) suture materials on the amount and decay curves of surgically induced astigmatism following intraocular lens (IOL) surgery. Patients with Mersilene and nylon sutures had the highest amounts of induced with-the-rule (WTR) cylinder (significantly more than Prolene) at one day after surgery. However, the WTR cylinder decayed rapidly for nylon during the first three months but more slowly for Mersilene because of its lack of stretchability. The Prolene group had the lowest level of induced WTR cylinder at one day, but against-the-rule (ATR) drift occurred, leaving cases with ATR astigmatism by a year. The nylon group had the second highest amount of induced WTR cylinder at one day, which had decayed to ATR cylinder by five months. Between one and two years postoperatively, the nylon group experienced a significant ATR shift. The amount of early induced WTR cylinder seemed to be related to the knot-tying technique and tissue gripping characteristics, whereas the shape of the decay curve was related to the material characteristics of the suture. PMID:1531234

  12. 3D astigmatic depth sensing camera

    NASA Astrophysics Data System (ADS)

    Birch, Gabriel C.; Tyo, J. Scott; Schwiegerling, Jim

    2011-10-01

    Three-dimensional displays have become increasingly present in consumer markets. However, the ability to capture threedimensional images inexpensively and without major modifications to current cameras is uncommon. Our goal is to create a modification to a common commercial camera that allows a three dimensional reconstruction. We desire such an imaging system to be inexpensive and easy to use. Furthermore, we require that any three-dimensional modification to a camera does not reduce its resolution. Here we present a possible solution to this problem. A commercial digital camera is used with a projector system with astigmatic focus to capture images of a scene. By using an astigmatic projected pattern we can create two different focus depths for horizontal and vertical features of the projected pattern, thereby encoding depth. This projector could be integrated into the flash unit of the camera. By carefully choosing a pattern we are able to exploit this differential focus in image processing. Wavelet transforms are performed on the image that pick out the projected pattern. By taking ratios of certain wavelet coefficients we are able to correlate the distance an object at a particular transverse position is from the camera to the contrast ratios. We present our information regarding construction, calibration, and images produced by this system. The nature of linking a projected pattern design and image processing algorithms will be discussed.

  13. Accommodation in Astigmatic Children During Visual Task Performance

    PubMed Central

    Harvey, Erin M.; Miller, Joseph M.; Apple, Howard P.; Parashar, Pavan; Twelker, J. Daniel; Crescioni, Mabel; Davis, Amy L.; Leonard-Green, Tina K.; Campus, Irene; Sherrill, Duane L.

    2014-01-01

    Purpose. To determine the accuracy and stability of accommodation in uncorrected children during visual task performance. Methods. Subjects were second- to seventh-grade children from a highly astigmatic population. Measurements of noncycloplegic right eye spherical equivalent (Mnc) were obtained while uncorrected subjects performed three visual tasks at near (40 cm) and distance (2 m). Tasks included reading sentences with stimulus letter size near acuity threshold and an age-appropriate letter size (high task demands) and viewing a video (low task demand). Repeated measures ANOVA assessed the influence of astigmatism, task demand, and accommodative demand on accuracy (mean Mnc) and variability (mean SD of Mnc) of accommodation. Results. For near and distance analyses, respectively, sample size was 321 and 247, mean age was 10.37 (SD 1.77) and 10.30 (SD 1.74) years, mean cycloplegic M was 0.48 (SD 1.10) and 0.79 diopters (D) (SD 1.00), and mean astigmatism was 0.99 (SD 1.15) and 0.75 D (SD 0.96). Poor accommodative accuracy was associated with high astigmatism, low task demand (video viewing), and high accommodative demand. The negative effect of accommodative demand on accuracy increased with increasing astigmatism, with the poorest accommodative accuracy observed in high astigmats (≥3.00 D) with high accommodative demand/high hyperopia (1.53 D and 2.05 D of underaccommodation for near and distant stimuli, respectively). Accommodative variability was greatest in high astigmats and was uniformly high across task condition. No/low and moderate astigmats showed higher variability for the video task than the reading tasks. Conclusions. Accuracy of accommodation is reduced in uncorrected children with high astigmatism and high accommodative demand/high hyperopia, but improves with increased visual task demand (reading). High astigmats showed the greatest variability in accommodation. PMID:25103265

  14. Lack of oblique astigmatism in the chicken eye.

    PubMed

    Maier, Felix M; Howland, Howard C; Ohlendorf, Arne; Wahl, Siegfried; Schaeffel, Frank

    2015-04-01

    Primate eyes display considerable oblique off-axis astigmatism which could provide information on the sign of defocus that is needed for emmetropization. The pattern of peripheral astigmatism is not known in the chicken eye, a common model of myopia. Peripheral astigmatism was mapped out over the horizontal visual field in three chickens, 43 days old, and in three near emmetropic human subjects, average age 34.7years, using infrared photoretinoscopy. There were no differences in astigmatism between humans and chickens in the central visual field (chicks -0.35D, humans -0.65D, n.s.) but large differences in the periphery (i.e. astigmatism at 40° in the temporal visual field: humans -4.21D, chicks -0.63D, p<0.001, unpaired t-test). The lack of peripheral astigmatism in chicks was not due to differences in corneal shape. Perhaps related to their superior peripheral optics, we found that chickens had excellent visual performance also in the far periphery. Using an automated optokinetic nystagmus paradigm, no difference was observed in spatial visual performance with vision restricted to either the central 67° of the visual field or to the periphery beyond 67°. Accommodation was elicited by stimuli presented far out in the visual field. Transscleral images of single infrared LEDs showed no sign of peripheral astigmatism. The chick may be the first terrestrial vertebrate described to lack oblique astigmatism. Since corneal shape cannot account for the difference in astigmatism in humans and chicks, it must trace back to the design of the crystalline lens. The lack of peripheral astigmatism in chicks also excludes a role in emmetropization.

  15. Optical imaging module for astigmatic detection system.

    PubMed

    Wang, Wei-Min; Cheng, Chung-Hsiang; Molnar, Gabor; Hwang, Ing-Shouh; Huang, Kuang-Yuh; Danzebrink, Hans-Ulrich; Hwu, En-Te

    2016-05-01

    In this paper, an optical imaging module design for an astigmatic detection system (ADS) is presented. The module is based on a commercial optical pickup unit (OPU) and it contains a coaxial illuminant for illuminating a specimen. Furthermore, the imaging module facilitates viewing the specimen and the detection laser spot of the ADS with a lateral resolution of approximately 1 μm without requiring the removal of an element of the OPU. Two polarizers and one infrared filter are used to eliminate stray laser light in the OPU and stray light produced by the illuminant. Imaging modules designed for digital versatile disks (DVDs) and Blu-ray DVDs were demonstrated. Furthermore, the module can be used for imaging a small cantilever with approximate dimensions of 2 μm (width) × 5 μm (length), and therefore, it has the potential to be used in high-speed atomic force microscopy. PMID:27250434

  16. Unexpected postmortem diagnosis of acanthamoeba meningoencephalitis in an immunocompetent child

    PubMed Central

    Binesh, Fariba; Karimi, Mehran; Navabii, Hossein

    2011-01-01

    Meningoencephalitis caused by Acanthamoeba spp. is a rare opportunistic infection, difficult to diagnose and treat, which causes death in almost all cases. Here, the authors report a 5-year-old Iranian immunocompetent girl who died of fulminant acanthamoeba meningoencephalitis. To the authors’ knowledge, this is the first case of acanthamoeba meningoencephalitis in Iran. PMID:22679147

  17. Induced corneal astigmatism with hydrophilic contact lenses.

    PubMed

    Morgan, J F

    1975-04-01

    Changes in keratometer readings were measured in 87 patients, wearing hydrophilic contact lenses for three to more than eighteen months. Twenty-four eyes in the group had an increase of +0.75 or more in the keratometer readings, which invariably involved the vertical reading and was often associated with a distortion of the mire reflex. The change was high as +2.75 diopters. If greater than +1.00 diopter, it was associated with decreased visual acuity with forward correction and with the hydrophilic contact lenses. All but one of the patients who showedchanges of greater than +0.75 diopters over their baseline keratometer readings, were wearing their lenses on an average of 14-16 hours a day. The keratometer readings reverted to the baseline levels with a loss of the distrotion, if the patient reduced the wearing time to less than 12 hours daily. We believe that a maximum average daily wearing time of 12 hours is the safety limit required to minimize the development of induced corneal astigmatism.

  18. Acanthamoeba keratitis challenges a case report.

    PubMed

    Cristina, Stan; Cristina, Vlăduţiu; Mihaela, Popovici

    2016-01-01

    Acanthamoeba keratitis is a rare, chronic, mainly contact lens-related infection caused by a free-living amoeba found ubiquitously in water and soil. A case of a 9-year-old child, who presented to our clinic with painful, red left eye, associated with photophobia, and decreased visual acuity, wais reported. The clinical examination revealed a discoid opacity inferiorly bounded by a dense, gray infiltrate. The progressive nature of the corneal infiltrate, the epithelial defect, and the lack of response to treatment was highly suggestive for Acanthamoeba keratitis. The distinctiveness of this case was the presence of Acanthamoeba keratitis in a child without a history of trauma or contact lens usage, the lack of an appropriate diagnosis and management of this vision-threatening infection. PMID:27220232

  19. Three Methods for Correction of Astigmatism during Phacoemulsification

    PubMed Central

    Mohammad-Rabei, Hossein; Mohammad-Rabei, Elham; Espandar, Goldis; Javadi, Mohammad Ali; Jafarinasab, Mohammad Reza; Hashemian, Seyed Javad; Feizi, Sepehr

    2016-01-01

    Purpose: To compare the safety and efficacy of three methods for correcting pre-existing astigmatism during phacoemulsification. Methods: This prospective, comparative, non-randomized study was conducted from March 2010 to January 2011, and included patients with keratometric astigmatism ≥1.25 D undergoing cataract surgery. Astigmatism was corrected using the following approaches: limbal relaxing incisions (LRI) on the steep meridian, extension and suturing of the phaco incision created at the steep meridian (extended-on-axis incision, EOAI), and toric intraocular lens (tIOL) implantation. Keratometric and refractive astigmatism were evaluated 1, 8, and 24 weeks postoperatively. Results: Eighty-three eyes of 72 patients (35 male and 37 female) with mean age of 62.4 ± 14.3 (range, 41-86) years were enrolled. The astigmatism was corrected by using the LRI, EOAI and tIOL implantation methods in 17, 33 and 33 eyes, respectively. Postoperative uncorrected distance visual acuity (UDVA) was significantly improved in all three groups. The difference in postoperative UDVA was not statistically significant among the study groups throughout follow-up except at week 24, when UCVA was significantly better in the tIOL group as compared to the EOAI group (P = 0.024). There is no statistically significant difference of correction index and index of success between three groups at week 24 (P = 0.085 and P = 0.085 respectively). Conclusion: There was no significant difference in astigmatism reduction among the three methods of astigmatism correction during phacoemulsification. Each of these methods can be used at the discretion of the surgeon. PMID:27413496

  20. Bilateral upper and lower eyelid severe psoriasiform blepharitis: case report and review of literature.

    PubMed

    Zhu, Feilin; Tao, Jeremiah P

    2011-01-01

    The purpose of the present study is to describe a case of severe, psoriasiform blepharitis by means of a case report and literature review. A 44-year-old man developed chronic blepharitis and tearing months after bilateral cataract surgery. Exam showed diffuse quad-eyelid erythema, discharge, edema, madarosis, and scale. He also had insufficient tear drainage due to bilateral upper eyelid cicatricial punctal atresia with bilateral lower eyelid punctal stenosis. Biopsy of the lower eyelids exhibited psoriasiform hyperplasia. Topical 0.1% tacrolimus achieved improvement but caused some subjective eye irritation. Psoriasiform dermatitis manifesting on the eyelids is rare, may be associated with insufficient tear drainage, and may respond favorably to 0.1% tacrolimus.

  1. Staphylococcus aureus Blepharitis Associated with Multiple Corneal Stromal Microabscess, Stromal Edema, and Uveitis.

    PubMed

    Boto-de-los-Bueis, Ana; del Hierro Zarzuelo, Almudena; García Perea, Adela; de Pablos, Manuela; Pastora, Natalia; Noval, Susana

    2015-04-01

    We report a case of an immunocompetent woman with atypical marginal keratitis. She presented with recurrent episodes of multiples microabscess distributed in a triangular pattern associated with stromal oedema and anterior chamber uveitis, affecting both eyes, but not simultaneously. The episodes responded to steroid drops, corneal inflammation was coincidental with a worsening of her blepharitis in the affected eye and S. aureus was isolated from the lids.

  2. Staphylococcus aureus Blepharitis Associated with Multiple Corneal Stromal Microabscess, Stromal Edema, and Uveitis.

    PubMed

    Boto-de-los-Bueis, Ana; del Hierro Zarzuelo, Almudena; García Perea, Adela; de Pablos, Manuela; Pastora, Natalia; Noval, Susana

    2015-04-01

    We report a case of an immunocompetent woman with atypical marginal keratitis. She presented with recurrent episodes of multiples microabscess distributed in a triangular pattern associated with stromal oedema and anterior chamber uveitis, affecting both eyes, but not simultaneously. The episodes responded to steroid drops, corneal inflammation was coincidental with a worsening of her blepharitis in the affected eye and S. aureus was isolated from the lids. PMID:24410378

  3. Comparison of therapeutic effects of topical azithromycin solution and systemic doxycycline on posterior blepharitis

    PubMed Central

    Zandian, Mehdi; Rahimian, Neda; Soheilifar, Sanaz

    2016-01-01

    AIM To compare the effect of azithromycin drop and doxycycline capsule on treatment of posterior blepharitis. METHODS Fifty patients (100 eyes) with moderate posterior blepharitis, randomly divided into two therapeutic groups; all the patients got warm eyelid compress and massage three times a day for 3wk. In addition the first group got azithromycin 1% drop, twice daily for 1wk and then one drop daily for 2wk. The second group got oral doxycycline 100 mg daily for 3wk. At the end of the research, patients' signs and symptoms were compared together. ANOVA, Chi-square and Mann-Whitney tests were used for statistical analysis. RESULTS Topical therapy with azithromycin and oral therapy with doxycycline relieved signs and symptoms after 3wk. There were no significant differences between symptoms healing rate and foreign body sensation healing in these two groups (P>0.05). However, azithromycin drop was more effective in reduction of eye redness and doxycycline was more effective in meibomian glands plugging healing and reducing the corneal staining. CONCLUSION Topical azithromycin could have similar effects as oral doxycycline on posterior blepharitis in improving subjective symptoms. However, doxycycline can reduce objective signs such as ocular surface staining and meibomian gland plugging more than azithromycin. PMID:27500111

  4. Genotypic Identification of Acanthamoeba sp. Isolates Associated with an Outbreak of Acanthamoeba keratitis (AK)

    PubMed Central

    Booton, Gregory C.; Joslin, Charlotte E.; Shoff, Megan; Tu, Elmer Y.; Kelly, Daryl J.; Fuerst, Paul A.

    2009-01-01

    Purpose Significant increases in Acanthamoeba keratitis (AK) cases have been observed in the Chicago-Gary-Kenosha area since June, 2003. It was hypothesized that increased rates of AK infections may be due to changes resulting from changes in municipal water treatment, or, alternatively, a more pathogenic strain of Acanthamoeba may be responsible. Methods Previous sequence analysis of the 18S rDNA of Acanthamoeba isolates resulted in the identification of 15 different genotypic classes. These analyses indicate AK cases are predominantly associated (~97%) with a single genotype (designated T4) of Acanthamoeba, and rarely with other genotypes (eg., T3 and T11). In this study we test the hypothesis that a new or more pathogenic genotype of Acanthamoeba is the cause of the recent surge in AK. Results We determined the genotype of 15 Acanthamoeba sp. isolates from AK cases from this outbreak using sequence analysis of a region of the 18S rDNA. Our results indicate that these isolates are predominantly genotype T4 (87%), with the remaining isolates being genotype T3 (13%). Both genotypes have previously been observed in AK cases. Conclusion There is no support for the hypothesis that the current AK outbreak is associated with infection by a new, more pathogenic, Acanthamoeba genotype. In addition, these results offer support for the hypothesis that the increased AK incidence may be due to changes in water treatment protocols leading to increased bacterial colonization of the water supply, and subsequent increases of already present Acanthamoeba sp, ultimately culminating in an increase of AK cases. PMID:19512903

  5. Small Incision Lenticule Extraction for Postkeratoplasty Myopia and Astigmatism

    PubMed Central

    Ibrahim, Osama; Shehata, Kitty; Abdalla, Moones F.

    2016-01-01

    Purpose. To evaluate the visual and refractive outcomes after small incision lenticule extraction (SMILE) for treating myopia and myopic astigmatism after penetrating keratoplasty (PKP). Design. Case-series. Methods. Ten eyes of 10 patients with previous PKP and residual myopic astigmatism for whom pentacam imaging and thickness measurements were acceptable for laser vision correction. Manifest refraction (MR), uncorrected distance visual acuity (UDVA), and corrected distance visual acuity (CDVA) were obtained preoperatively and one day, one week, and one, 3, and 6 months postoperatively. Cases were operated on the VisuMax® femtosecond laser platform with 500 kHz repetition rate. Results. The mean correction ratio for spherical errors was 0.84 ± 0.19 D and for the mean refractive spherical equivalent (MRSE) was 0.79 ± 0.13 D. Vector analysis showed a mean astigmatism reduction at the intended axis of 67 ± 25.25%, a correction index of 0.81 ± 0.21, and an overall mean percentage of success of astigmatism surgery of 53 ± 37.9%. The postoperative MRSE was stable throughout the 6-month follow-up period. The efficacy index was 0.93 and the safety index was 1.12. Conclusion. SMILE for correction of post-PKP myopia and astigmatism is effective, safe, and stable with moderate accuracy and predictability. Centration of the treatment within the grafts was easily performed. PMID:27446606

  6. Medical interventions for acanthamoeba keratitis

    PubMed Central

    Alkharashi, Majed; Lindsley, Kristina; Law, Hua Andrew; Sikder, Shameema

    2016-01-01

    Background Acanthamoeba are microscopic, free-living, single-celled organisms which can infect the eye and lead to Acanthamoeba keratitis (AK). AK can result in loss of vision in the infected eye or loss of eye itself; however, there are no formal guidelines or standards of care for the treatment of AK. Objectives To evaluate the relative effectiveness and safety of medical therapy for the treatment of AK. Search methods We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (2015, Issue 1), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to January 2015), EMBASE (January 1980 to January 2015), PubMed (1948 to January 2015), Latin American and Caribbean Health Sciences Literature Database (LILACS) (1982 to January 2015), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic search for trials. We last searched the electronic databases on 9 January 2015. Selection criteria We included randomized controlled trials (RCTs) of medical therapy for AK, regardless of the participants' age, sex, or etiology of disease. We included studies that compared either anti-amoeba therapy (drugs used alone or in combination with other medical therapies) with no anti-amoeba therapy or one anti-amoeba therapy with another anti-amoeba therapy. Data collection and analysis Two authors independently screened search results and full-text reports, assessed risk of bias, and abstracted data. We used standard methodological procedures as set forth by the Cochrane Collaboration. Main results We included one RCT (56 eyes of 55 participants) in this review. The study compared two types of topical biguanides for the treatment of AK

  7. Autophagy inhibitors as a potential antiamoebic treatment for Acanthamoeba keratitis.

    PubMed

    Moon, Eun-Kyung; Kim, So-Hee; Hong, Yeonchul; Chung, Dong-Il; Goo, Youn-Kyoung; Kong, Hyun-Hee

    2015-07-01

    Acanthamoeba cysts are resistant to extreme physical and chemical conditions. Autophagy is an essential pathway for encystation of Acanthamoeba cells. To evaluate the possibility of an autophagic Acanthamoeba encystation mechanism, we evaluated autophagy inhibitors, such as 3-methyladenine (3MA), LY294002, wortmannin, bafilomycin A, and chloroquine. Among these autophagy inhibitors, the use of 3MA and chloroquine showed a significant reduction in the encystation ratio in Acanthamoeba cells. Wortmannin also inhibited the formation of mature cysts, while LY294002 and bafilomycin A did not affect the encystation of Acanthamoeba cells. Transmission electron microscopy revealed that 3MA and wortmannin inhibited autophagy formation and that chloroquine interfered with the formation of autolysosomes. Inhibition of autophagy or autolysosome formation resulted in a significant block in the encystation in Acanthamoeba cells. Clinical treatment with 0.02% polyhexamethylene biguanide (PHMB) showed high cytopathic effects on Acanthamoeba trophozoites and cysts; however, it also revealed high cytopathic effects on human corneal epithelial cells. In this study, we investigated effects of the combination of a low (0.00125%) concentration of PHMB with each of the autophagy inhibitors 3MA, wortmannin, and chloroquine on Acanthamoeba and human corneal epithelial cells. These new combination treatments showed low cytopathic effects on human corneal cells and high cytopathic effects on Acanthamoeba cells. Taken together, these results provide fundamental information for optimizing the treatment of Acanthamoeba keratitis.

  8. Quasi-Bessel beams from asymmetric and astigmatic illumination sources.

    PubMed

    Müller, Angelina; Wapler, Matthias C; Schwarz, Ulrich T; Reisacher, Markus; Holc, Katarzyna; Ambacher, Oliver; Wallrabe, Ulrike

    2016-07-25

    We study the spatial intensity distribution and the self-reconstruction of quasi-Bessel beams produced from refractive axicon lenses with edge emitting laser diodes as asymmetric and astigmatic illumination sources. Comparing these to a symmetric mono-mode fiber source, we find that the asymmetry results in a transition of a quasi-Bessel beam into a bow-tie shaped pattern and eventually to a line shaped profile at a larger distance along the optical axis. Furthermore, we analytically estimate and discuss the effects of astigmatism, substrate modes and non-perfect axicons. We find a good agreement between experiment, simulation and analytic considerations. Results include the derivation of a maximal axicon angle related to astigmatism of the illuminating beam, impact of laser diode beam profile imperfections like substrate modes and a longitudinal oscillation of the core intensity and radius caused by a rounded axicon tip. PMID:27464190

  9. Graded nonintersecting transverse incisions for correction of idiopathic astigmatism.

    PubMed

    Thornton, S P; Sanders, D R

    1987-01-01

    We present the results of a consecutive series of graded transverse (T) incisions for correcting idiopathic astigmatism evaluated by vector analysis, a method not previously used to report T-incision results. In fact, no clinical studies on the results of the T-incision method have been reported. For comparison with conventional reporting methods, the results of graded T incisions on a series of eyes were evaluated, using both vector analysis and simplified analytic procedures. Sixty eyes were evaluated following surgery based on the Thornton guide for astigmatism correction. The mean preoperative cylinder in the series was 1.5 diopters (D) (SD = 0.43, range 1.00 D to 2.25 D); mean postoperative cylinder was 0.4 D (SD = 0.61, range 0 to 3.75 D). The mean decrease of 1.1 D was statistically significant. The results show that it is possible to quantify astigmatism correction using vector analysis. PMID:3559948

  10. Twenty years of acanthamoeba diagnostics in Austria.

    PubMed

    Walochnik, Julia; Scheikl, Ute; Haller-Schober, Eva-Maria

    2015-01-01

    Acanthamoebae are the causative agents of an often seriously progressing keratitis (AK) occurring predominantly in contact lens wearers and can cause several disseminating infections potentially resulting in granulomatous amoebic encephalitis (GAE) in the immunocompromised host. Our institution is the Austrian reference laboratory for Acanthamoeba diagnostics and the aim of this study was to give an overview of proven cases of Acanthamoeba infections in Austria during the past 20 yr. All samples of patients with suspected AK or GAE were screened for Acanthamoeba spp. by culture and/or PCR and the detected amoebae were genotyped. Altogether, 154 cases of AK and three cases of GAE were diagnosed. Age of the AK patients ranged from 8 to 82 yr (mean 37.8) and 58% of the patients were female. Approximately 89% of the AK patients were contact lens wearers, almost all cases were unilateral and 19% of the patients required a keratoplasty. Age of the GAE patients ranged from 2 to 25 yr (mean 14.7), all were HIV-negative, but two were severely immunosuppressed at the time of diagnosis. The predominant genotype in the AK cases was T4, other genotypes found were T3, T5, T6, T10 and T11. The three GAE cases involved genotypes T2, T4 and T5.

  11. Twenty Years of Acanthamoeba Diagnostics in Austria

    PubMed Central

    Walochnik, Julia; Scheikl, Ute; Haller-Schober, Eva-Maria

    2015-01-01

    Acanthamoebae are the causative agents of an often seriously progressing keratitis (AK) occurring predominantly in contact lens wearers and can cause several disseminating infections potentially resulting in granulomatous amoebic encephalitis (GAE) in the immunocompromised host. Our institution is the Austrian reference laboratory for Acanthamoeba diagnostics and the aim of this study was to give an overview of proven cases of Acanthamoeba infections in Austria during the past 20 yr. All samples of patients with suspected AK or GAE were screened for Acanthamoeba spp. by culture and/or PCR and the detected amoebae were genotyped. Altogether, 154 cases of AK and three cases of GAE were diagnosed. Age of the AK patients ranged from 8 to 82 yr (mean 37.8) and 58% of the patients were female. Approximately 89% of the AK patients were contact lens wearers, almost all cases were unilateral and 19% of the patients required a keratoplasty. Age of the GAE patients ranged from 2 to 25 yr (mean 14.7), all were HIV-negative, but two were severely immunosuppressed at the time of diagnosis. The predominant genotype in the AK cases was T4, other genotypes found were T3, T5, T6, T10 and T11. The three GAE cases involved genotypes T2, T4 and T5. PMID:25047131

  12. [Efficacy of physiotherapy and hygienic procedures in treatment of adults and children with chronic blepharitis and dry eye syndrome].

    PubMed

    Prozornaia, L P; Brzhevskiĭ, V V

    2013-01-01

    110 patients aged from 3 to 42 years old were examined to estimate the efficacy of chronic blepharitis treatment: 50 patients with chronic blepharitis and dry eye syndrome (DES), 28 with DES due to computer vision syndrome and 32 with isolated chronic blepharitis. All patients received eyelid massage. If the secretion was too thick and difficult to evacuate from meibomian glands then duct probing was performed. In addition a complex of hygienic procedures was performed using phytoproducts ("Geltec-Medika", Russia): blepharoshampoo, blepharolotion, blepharogel 1 and 2. Moist warm pads (with blepharolotion and calendula extraction) were applied on the eyelids in 25 patients. Massage and probing of meibomian gland ducts and hygienic procedures were showed to be effective in management of clinical signs of chronic blepharitis including coexisting DES. Moist warm pads improve efficacy of background therapy in patients with meibomian gland hypofunction and have no effect in blepharitis with excessive meibomian gland secretion. Eyelid hygiene was showed to be effective in adults and children as well including infants.

  13. Interaction of axial and oblique astigmatism in theoretical and physical eye models.

    PubMed

    Liu, Tao; Thibos, Larry N

    2016-09-01

    The interaction between oblique and axial astigmatism was investigated analytically (generalized Coddington's equations) and numerically (ray tracing) for a theoretical eye model with a single refracting surface. A linear vector-summation rule for power vector descriptions of axial and oblique astigmatism was found to account for their interaction over the central 90° diameter of the visual field. This linear summation rule was further validated experimentally using a physical eye model measured with a laboratory scanning aberrometer. We then used the linear summation rule to evaluate the relative contributions of axial and oblique astigmatism to the total astigmatism measured across the central visual field. In the central visual field, axial astigmatism dominates because the oblique astigmatism is negligible near the optical axis. At intermediate eccentricities, axial and oblique astigmatism may have equal magnitude but orthogonal axes, which nullifies total astigmatism at two locations in the visual field. At more peripheral locations, oblique astigmatism dominates axial astigmatism, and the axes of total astigmatism become radially oriented, which is a trait of oblique astigmatism. When eccentricity is specified relative to a foveal line-of-sight that is displaced from the eye's optical axis, asymmetries in the visual field map of total astigmatism can be used to locate the optical axis empirically and to estimate the relative contributions of axial and oblique astigmatism at any retinal location, including the fovea. We anticipate the linear summation rule will benefit many topics in vision science (e.g., peripheral correction, emmetropization, meridional amblyopia) by providing improved understanding of how axial and oblique astigmatism interact to produce net astigmatism. PMID:27607493

  14. Impact of astigmatism and high-order aberrations on subjective best focus.

    PubMed

    Marcos, Susana; Velasco-Ocana, Miriam; Dorronsoro, Carlos; Sawides, Lucie; Hernandez, Martha; Marin, Gildas

    2015-08-01

    We studied the role of native astigmatism and ocular aberrations on best-focus setting and its shift upon induction of astigmatism in 42 subjects (emmetropes, myopes, hyperopes, with-the-rule [WTR] and against-the-rule [ATR] myopic astigmats). Stimuli were presented in a custom-developed adaptive optics simulator, allowing correction for native aberrations and astigmatism induction (+1 D; 6-mm pupil). Best-focus search consisted on randomized-step interleaved staircase method. Each subject searched best focus for four different images, and four different conditions (with/without aberration correction, with/without astigmatism induction). The presence of aberrations induced a significant shift in subjective best focus (0.4 D; p < 0.01), significantly correlated (p = 0.005) with the best-focus shift predicted from optical simulations. The induction of astigmatism produced a statistically significant shift of the best-focus setting in all groups under natural aberrations (p = 0.001), and in emmetropes and in WTR astigmats under corrected aberrations (p < 0.0001). Best-focus shift upon induced astigmatism was significantly different across groups, both for natural aberrations and AO-correction (p < 0.0001). Best focus shifted in opposite directions in WTR and ATR astigmats upon induction of astigmatism, symmetrically with respect to the best-focus shift in nonastigmatic myopes. The shifts are consistent with a bias towards vertical and horizontal retinal blur in WTR and ATR astigmats, respectively, indicating adaptation to native astigmatism.

  15. The Value of Cytology Smears for Acanthamoeba Keratitis

    PubMed Central

    Schaefer, Jamie L.; Paterson, Joyce; Liu, Weiguo; Gonzalez-Fernandez, Federico

    2016-01-01

    Purpose. Acanthamoeba keratitis remains a difficult diagnosis despite advances in genetic and imaging technologies. The purpose of this paper is to highlight the utility of cytology smears for diagnosis of Acanthamoeba keratitis. Methods. This is a case study of the diagnostic course for a patient with suspected Acanthamoeba keratitis. Results. A 40-year-old male with poor contact lens hygiene presented with severe left eye pain. Slit lamp examination showed two peripheral ring infiltrates without an epithelial defect. The epithelium over both infiltrates was removed with a Kimura spatula. Half of the sample was smeared on a dry microscope slide and the other half was submitted for Acanthamoeba culture and PCR. Both culture and PCR were negative for Acanthamoeba, but hematoxylin and eosin stain of the smear revealed double-walled cysts. Conclusion. H&E staining of corneal cytology specimens is an efficient and readily available test for diagnosis of Acanthamoeba keratitis. PMID:27403362

  16. Is there evidence of sexual reproduction (meiosis) in Acanthamoeba?

    PubMed Central

    Khan, Naveed A.; Siddiqui, Ruqaiyyah

    2015-01-01

    Evolution of independently breeding species into males and females (gametes) has remained a puzzle. Given the significant advantages of sexual reproduction over asexual reproduction as a long-term species survival strategy; here, we pose the question whether there is some form of meiosis in Acanthamoeba species, which represents our ancient lineage. The recently available Acanthamoeba genome revealed several genes implicated in meiosis in sexual eukaryotes such as Spo11, Mre11, Rad50, Rad51, Rad52, Mnd1, Dmc1, Msh, and Mlh, suggesting that Acanthamoeba is capable of some form of meiosis, inferring the presence of sexual reproduction in Acanthamoeba, and that meiosis evolved early in eukaryotic evolution. PMID:25800982

  17. Phylogenetic evidence for a new genotype of Acanthamoeba (Amoebozoa, Acanthamoebida).

    PubMed

    Corsaro, Daniele; Venditti, Danielle

    2010-06-01

    Acanthamoeba are widespread free-living amoebae, able to cause infection in animals, with keratitis and granulomatous encephalitis as major diseases in humans. Recent developments in the subgenus classification are based on the determination of the nucleotide sequence of the 18S rDNA. By this mean, Acanthamoeba have been clustered into 15 sequence types or genotypes, called T1 to T15. In this study, we analysed near full 18S rDNA of an Acanthamoeba recovered from an environmental sample and various unidentified Acanthamoeba sequences retrieved from GenBank. We provided phylogenetic evidence for a new genotype, which we proposed to name T16.

  18. Is there evidence of sexual reproduction (meiosis) in Acanthamoeba?

    PubMed

    Khan, Naveed A; Siddiqui, Ruqaiyyah

    2015-06-01

    Evolution of independently breeding species into males and females (gametes) has remained a puzzle. Given the significant advantages of sexual reproduction over asexual reproduction as a long-term species survival strategy; here, we pose the question whether there is some form of meiosis in Acanthamoeba species, which represents our ancient lineage. The recently available Acanthamoeba genome revealed several genes implicated in meiosis in sexual eukaryotes such as Spo11, Mre11, Rad50, Rad51, Rad52, Mnd1, Dmc1, Msh, and Mlh, suggesting that Acanthamoeba is capable of some form of meiosis, inferring the presence of sexual reproduction in Acanthamoeba, and that meiosis evolved early in eukaryotic evolution.

  19. Amebic meningoencephalitis caused by Acanthamoeba castellani in a dog.

    PubMed

    Pearce, J R; Powell, H S; Chandler, F W; Visvesvara, G S

    1985-11-01

    A natural infection of Acanthamoeba castellani, a free-living ameba, was determined to be the cause of acute, hemorrhagic, necrotizing amebic meningoencephalitis in a dog. This case is unique because previous reports of infection by the Acanthamoeba spp in dogs have not indicated its presence in the brain. Naturally developing meningoencephalitis by Acanthamoeba spp in the dog may have a pathogenesis similar to that of human beings. The ameba in this case also was observed in the lungs and kidneys, which are believed to be the primary sites of lesions in human beings that develop amebic meningoencephalitis from Acanthamoeba spp. PMID:3932273

  20. Identification of Paenibacillus as a Symbiont in Acanthamoeba.

    PubMed

    Maschio, Vinicius José; Corção, Gertrudes; Bücker, Francielle; Caumo, Karin; Rott, Marilise Brittes

    2015-09-01

    Amoebae of the genus Acanthamoeba occur worldwide and in addition to being pathogens, are important vehicles for microorganisms with clinical and environmental importance. This study aimed to evaluate the profiling of endosymbionts in 12 isolates of Acanthamoeba using V3 region of 16S rDNA denaturing gradient gel electrophoresis (DGGE) and sequencing. The DGGE enabled us to characterize the endosymbionts diversity in isolates of Acanthamoeba, and to identify Paenibacillus sp., an emerging pathogen, as an amoebic endosymbiont. The results of this study demonstrated that Acanthamoeba is capable of transporting a large number of endosymbionts. This is the first study that reports, the presence of Paenibacillus sp. as amebic symbiont.

  1. Area 51: How do Acanthamoeba invade the central nervous system?

    PubMed

    Siddiqui, Ruqaiyyah; Emes, Richard; Elsheikha, Hany; Khan, Naveed Ahmed

    2011-05-01

    Acanthamoeba granulomatous encephalitis generally develops as a result of haematogenous spread, but it is unclear how circulating amoebae enter the central nervous system (CNS) and cause inflammation. At present, the mechanisms which Acanthamoeba use to invade this incredibly well-protected area of the CNS and produce infection are not well understood. In this paper, we propose two key virulence factors: mannose-binding protein and extracellular serine proteases as key players in Acanthamoeba traversal of the blood-brain barrier leading to neuronal injury. Both molecules should provide excellent opportunities as potential targets in the rational development of therapeutic interventions against Acanthamoeba encephalitis.

  2. A Reciprocal Transformation for the Constant Astigmatism Equation

    NASA Astrophysics Data System (ADS)

    Hlaváč, Adam; Marvan, Michal

    2014-08-01

    We introduce a nonlocal transformation to generate exact solutions of the constant astigmatism equation z_{yy} + (1/z)_{xx} + 2 = 0. The transformation is related to the special case of the famous Bäcklund transformation of the sine-Gordon equation with the Bäcklund parameter λ = ±1. It is also a nonlocal symmetry.

  3. Correction of low corneal astigmatism in cataract surgery

    PubMed Central

    Leon, Pia; Pastore, Marco Rocco; Zanei, Andrea; Umari, Ingrid; Messai, Meriem; Negro, Corrado; Tognetto, Daniele

    2015-01-01

    AIM To evaluate and compare aspheric toric intraocular lens (IOL) implantation and aspheric monofocal IOL implantation with limbal relaxing incisions (LRI) to manage low corneal astigmatism (1.0-2.0 D) in cataract surgery. METHODS A prospective randomized comparative clinical study was performed. There were randomly recruited 102 eyes (102 patients) with cataracts associated with corneal astigmatism and divided into two groups. The first group received toric IOL implantation and the second one monofocal IOL implantation with peripheral corneal relaxing incisions. Outcomes considered were: visual acuity, postoperative residual astigmatism, endothelial cell count, the need for spectacles, and patient satisfaction. To determine the postoperative toric axis, all patients who underwent the toric IOL implantation were further evaluated using an OPD Scan III (Nidek Co, Japan). Follow-up lasted 6mo. RESULTS The mean uncorrected distance visual acuity (UCVA) and the best corrected visual acuity (BCVA) demonstrated statistically significant improvement after surgery in both groups. At the end of the follow-up the UCVA was statistically better in the patients with toric IOL implants compared to those patients who underwent implantation of monofocal IOL plus LRI. The mean residual refractive astigmatism was of 0.4 D for the toric IOL group and 1.1 D for the LRI group (P<0.01). No difference was observed in the postoperative endothelial cell count between the two groups. CONCLUSION The two surgical procedures demonstrated a significant decrease in refractive astigmatism. Toric IOL implantation was more effective and predictable compared to the limbal relaxing incision. PMID:26309869

  4. The Role of Omega-3 Dietary Supplementation in Blepharitis and Meibomian Gland Dysfunction (An AOS Thesis)

    PubMed Central

    Macsai, Marian S.

    2008-01-01

    Purpose Blepharitis and meibomian gland dysfunction (MGD) are common sources of complaints from patients. To evaluate the effect on ocular symptoms, ocular findings, and serum and meibomian gland contents, patients with blepharitis and MGD were prospectively evaluated to determine the effects of dietary supplementation with omega-3 fatty acids. Methods In a prospective randomized placebo-controlled masked trial, patients with simple obstructive MGD and blepharitis, who had discontinued all topical medications and tetracyclines, received oral omega-3 dietary supplementation consisting of two 1000-mg capsules 3 times a day. Patients were examined every 3 months for 1 year with the Ocular Surface Disease Index (OSDI) objective clinical measures, including tear production and stability, ocular surface and meibomian gland health, and biochemical plasma, red blood cell (RBC), and meibum evaluation. Primary outcome measures were change in tear breakup time (TBUT), meibum score, and overall OSDI score at 1 year. Results At 1 year, the omega-3 group had a 36% and 31% reduction in their omega-6 to omega-3 fatty acid ratios in RBCs and plasma, respectively (P = .3), whereas the placebo group demonstrated no change. At 12 months, the omega-3 group had an improvement in TBUT, OSDI score, and meibum score. Changes in meibum content were observed in the omega-3 group (P = .21); the level of meibum saturated fatty acids decreased. Conclusions This trial demonstrated a decrease in the RBC and plasma ratios of omega-6 to omega-3 in patients taking omega-3 dietary supplementation, as compared to controls, and improvements in their overall OSDI score, TBUT, and meibum score. This is the first demonstration of an induced change in the fatty acid saturation content in meibum as a result of dietary supplementation with omega-3 fatty acids. PMID:19277245

  5. A novel gammaherpesvirus in a large flying fox (Pteropus vampyrus) with blepharitis.

    PubMed

    Paige Brock, A; Cortés-Hinojosa, Galaxia; Plummer, Caryn E; Conway, Julia A; Roff, Shannon R; Childress, April L; Wellehan, James F X

    2013-05-01

    A novel gammaherpesvirus was identified in a large flying fox (Pteropus vampyrus) with conjunctivitis, blepharitis, and meibomianitis by nested polymerase chain reaction and sequencing. Polymerase chain reaction amplification and sequencing of 472 base pairs of the DNA-dependent DNA polymerase gene were used to identify a novel herpesvirus. Bayesian and maximum likelihood phylogenetic analyses indicated that the virus is a member of the genus Percavirus in the subfamily Gammaherpesvirinae. Additional research is needed regarding the association of this virus with conjunctivitis and other ocular pathology. This virus may be useful as a biomarker of stress and may be a useful model of virus recrudescence in Pteropus spp.

  6. [New method for treatment of chronic blepharitis associated with dry eye syndrome].

    PubMed

    Safonova, T N; Zabegaĭlo, A O; Fedorov, A A; Lukisheva, O V

    2014-01-01

    A new combined method for treatment of chronic blepharitis associated with dry eye syndrome is developed. A total of 25 patients were enrolled. The treatment implied the use of artificial tears, Restasis, and Blephasteam spectacle frame. The course included 20 procedures on daily basis. The monitoring period was 1 year. A pronounced anti-inflammatory, reparative, and moistening effect as well as stabilization of the precorneal film was achieved in short time. Owing to the combined approach, negative side effects (such as burning, conjunctival irritation, and fluctuating vision) were minimized. Repeated treatment courses maintained the positive therapeutic effect and prolongated the remission.

  7. [New method for treatment of chronic blepharitis associated with dry eye syndrome].

    PubMed

    Safonova, T N; Zabegaĭlo, A O; Fedorov, A A; Lukisheva, O V

    2014-01-01

    A new combined method for treatment of chronic blepharitis associated with dry eye syndrome is developed. A total of 25 patients were enrolled. The treatment implied the use of artificial tears, Restasis, and Blephasteam spectacle frame. The course included 20 procedures on daily basis. The monitoring period was 1 year. A pronounced anti-inflammatory, reparative, and moistening effect as well as stabilization of the precorneal film was achieved in short time. Owing to the combined approach, negative side effects (such as burning, conjunctival irritation, and fluctuating vision) were minimized. Repeated treatment courses maintained the positive therapeutic effect and prolongated the remission. PMID:24684070

  8. Acanthamoeba keratitis: improving the Scottish diagnostic service for the rapid molecular detection of Acanthamoeba species.

    PubMed

    Alexander, Claire Low; Coyne, Michael; Jones, Brian; Anijeet, Deepa

    2015-07-01

    Acanthamoeba species are responsible for causing the potentially sight-threatening condition, Acanthamoeba keratitis, which is commonly associated with contact lens use. In this report, we highlight the challenges faced using conventional laboratory identification methods to identify this often under-reported pathogen, and discuss the reasons for introducing the first national service in Scotland for the rapid and sensitive molecular identification of Acanthamoeba species. By comparing culture and molecular testing data from a total of 63 patients (n = 80 samples) throughout Scotland presenting with ocular eye disease, we describe the improvement in detection rates where an additional four positive cases were identified using a molecular assay versus culture. The testing of a further ten patients by confocal imaging is also presented. This report emphasizes the importance of continuing to improve clinical laboratory services to ensure a prompt, correct diagnosis and better prognosis, in addition to raising awareness of this potentially debilitating opportunistic pathogen.

  9. Influence of Acanthamoeba Genotype on Clinical Course and Outcomes for Patients with Acanthamoeba Keratitis in Spain

    PubMed Central

    Lumbreras-Fernández, Blanca; Martín-Navarro, Carmen M.; Valladares, Basilio; Lopez-Velez, Rogelio; Morcillo-Laiz, Rafael; Lorenzo-Morales, Jacob

    2014-01-01

    Genotype T4 is by far the most frequent genotype of Acanthamoeba keratitis (AK) and therefore has been considered the most virulent. This study included 14 cases of AK of genotype T4 and three cases of non-T4 genotype. We found that cases of non-T4 genotype had a worse response to medical therapy, greater need for surgical intervention, greater risk of extracorneal involvement, and remarkably poorer final visual outcome than those of T4 genotype, suggesting an association between Acanthamoeba virulence and genotype that requires additional case investigation. PMID:24430449

  10. Current Status of Acanthamoeba in Iran: A Narrative Review Article

    PubMed Central

    NIYYATI, Maryam; REZAEIAN, Mostafa

    2015-01-01

    Background: Free-living amoebae belonging to the genus Acanthamoeba have an environmental distribution. Amoebic keratitis due to these protozoan parasites continue to rise in Iran and worldwide. In Iran, there are various researches regarding both morphological and molecular identification of Acanthamoeba spp. in environmental and clinical samples. However, there is no thorough review about Acanthamoeba genotypes and their distribution in environmental sources such as water, dust and biofilm in Iran. Besides, according to increasing cases of Amoebic keratitis in the region awareness regarding the pathogenic potential of these sight-threatening amoebae is of utmost importance. Methods: We conducted a thorough review based on the database sources such as MEDLINE, PubMed and Google scholar. No restrictions were placed on study date, study design or language of publication. We searched all valuable and relevant information considering the occurrence of the Acanthamoeba in both environmental and clinical samples. Results: According to our thorough review Acanthamoeba belonging to T4 genotype is the most prevalent type strain in environmental and clinical samples in several regions in Iran and worldwide, however, there are reports regarding Acanthamoeba belonging to other genotypes such as T2, T3, T5, T6 and T11 and the mentioned point could leads us to more researches with the goal of presenting the real genotype dominance of Acanthamoeba and related disease in the country. Conclusion: Overall, the present review will focus on present status of genotypes of Acanthamoeba in Iran during recent years. PMID:26246812

  11. Acanthamoeba Encephalitis in Patient with Systemic Lupus, India

    PubMed Central

    Shirwadkar, Charudatt G.; Samant, Rohini; Sankhe, Milind; Deshpande, Ramesh; Yagi, Shigeo; Schuster, Frederick L.; Sriram, Rama

    2006-01-01

    We report a fatal case of encephalitis caused by Acanthamoeba in a 24-year-old woman from India with systemic lupus erythematosus. Diagnosis was made by identification of amebas in brain sections by immunofluorescence analysis and confirmed by demonstrating Acanthamoeba mitochondrial 16S rRNA gene DNA in brain tissue sections. PMID:16707057

  12. Cytotoxic effect of acriflavine against clinical isolates of Acanthamoeba spp.

    PubMed

    Polat, Zubeyda Akin; Karakus, Gulderen

    2013-02-01

    Acanthamoeba keratitis (AK) is a potentially devastating and sight-threatening infection of the cornea caused by the ubiquitous free-living amoebae, Acanthamoeba species. Its eradication is difficult because the amoebas encyst, making it highly resistant to anti-amoebic drugs. Acriflavine neutral (ACF) has been used for treatment of microbial infections for humans and fishes. The aim of our study was to evaluate the time-dependent cytotoxicities of ACF against Acanthamoeba spp. Trophozoites and cysts of three different strains (strain PAT06 Acanthamoeba castellanii, strain 2HH Acanthamoeba hatchetti, and strain 11DS A. hatchetti) of Acanthamoeba spp. were tested. All strains had been isolated from patients suffering from a severe AK. The effects of the ACF with the concentrations ranging from 15 to 500 mg mL(-1) on the cytotoxicity of Acanthamoeba strains were examined. ACF showed a time- and dose-dependent amebicidal action on the trophozoites and cysts. Pat06 (A. castellanii) was the most resistant, while strain 11DS (A. hatchetti) was the most sensitive. As a result, ACF could be concluded as a new agent for the treatment of Acanthamoeba infections. On the other hand, it still needs to be further evaluated by in vivo test systems to confirm the efficiency of its biological effect. PMID:23052789

  13. Utilisation of a Novel Test to Measure Severity and Treatment Efficacy of Posterior Blepharitis.

    PubMed

    Yun, Steven T H; Woo, David M; Chong, Calum W K; Liu, Ying; Francis, Katherine E; Shah, Saumil A; Agar, Ashish; Francis, Ian C

    2015-01-01

    Background. This study evaluated the effectiveness of managing posterior blepharitis (PB) using a novel Posterior Blepharitis Management Protocol (PBMP). Design. Prospective, consecutive case series with 100% followup to one month. Participants. 27 patients (54 eyes) with PB from an Ophthalmology practice in Sydney, Australia. Methods. Each patient's PB was assessed by grading the nature and expressibility of the central lower lid tarsal gland secretions on Compression Of The Eyelid (COTE). Patients were then instructed in detail to undertake daily PB management sessions at home using our modified PBMP. Main Outcome Measures. On a subjective scale, patients compared their symptoms at one month with baseline. COTE scores were reevaluated to assess the objective effectiveness of each individual's PBMP. COTE scoring was described as grades 1 (clear oil), 2 (pus, liquid), 3 (toothpaste-like secretions), and 4 (complete tarsal gland obstruction). Results. Patients reported a mean 77.8% ± 13.5% subjective improvement in symptoms. There was a trend towards improvement in COTE grading at one month compared with baseline: grades 1 (0 to 7.4%), 2a (22.2 to 16.6%), 2b (7.4 to 3.7%), 3 (18.5 to 27.7%), and 4 (51.8 to 44%). Conclusions. PBMP provided a rapid, inexpensive, simple, effective, and safe method of treating PB.

  14. Utilisation of a Novel Test to Measure Severity and Treatment Efficacy of Posterior Blepharitis

    PubMed Central

    Yun, Steven T. H.; Woo, David M.; Chong, Calum W. K.; Liu, Ying; Francis, Katherine E.; Shah, Saumil A.; Agar, Ashish; Francis, Ian C.

    2015-01-01

    Background. This study evaluated the effectiveness of managing posterior blepharitis (PB) using a novel Posterior Blepharitis Management Protocol (PBMP). Design. Prospective, consecutive case series with 100% followup to one month. Participants. 27 patients (54 eyes) with PB from an Ophthalmology practice in Sydney, Australia. Methods. Each patient's PB was assessed by grading the nature and expressibility of the central lower lid tarsal gland secretions on Compression Of The Eyelid (COTE). Patients were then instructed in detail to undertake daily PB management sessions at home using our modified PBMP. Main Outcome Measures. On a subjective scale, patients compared their symptoms at one month with baseline. COTE scores were reevaluated to assess the objective effectiveness of each individual's PBMP. COTE scoring was described as grades 1 (clear oil), 2 (pus, liquid), 3 (toothpaste-like secretions), and 4 (complete tarsal gland obstruction). Results. Patients reported a mean 77.8% ± 13.5% subjective improvement in symptoms. There was a trend towards improvement in COTE grading at one month compared with baseline: grades 1 (0 to 7.4%), 2a (22.2 to 16.6%), 2b (7.4 to 3.7%), 3 (18.5 to 27.7%), and 4 (51.8 to 44%). Conclusions. PBMP provided a rapid, inexpensive, simple, effective, and safe method of treating PB. PMID:26347811

  15. Utilisation of a Novel Test to Measure Severity and Treatment Efficacy of Posterior Blepharitis.

    PubMed

    Yun, Steven T H; Woo, David M; Chong, Calum W K; Liu, Ying; Francis, Katherine E; Shah, Saumil A; Agar, Ashish; Francis, Ian C

    2015-01-01

    Background. This study evaluated the effectiveness of managing posterior blepharitis (PB) using a novel Posterior Blepharitis Management Protocol (PBMP). Design. Prospective, consecutive case series with 100% followup to one month. Participants. 27 patients (54 eyes) with PB from an Ophthalmology practice in Sydney, Australia. Methods. Each patient's PB was assessed by grading the nature and expressibility of the central lower lid tarsal gland secretions on Compression Of The Eyelid (COTE). Patients were then instructed in detail to undertake daily PB management sessions at home using our modified PBMP. Main Outcome Measures. On a subjective scale, patients compared their symptoms at one month with baseline. COTE scores were reevaluated to assess the objective effectiveness of each individual's PBMP. COTE scoring was described as grades 1 (clear oil), 2 (pus, liquid), 3 (toothpaste-like secretions), and 4 (complete tarsal gland obstruction). Results. Patients reported a mean 77.8% ± 13.5% subjective improvement in symptoms. There was a trend towards improvement in COTE grading at one month compared with baseline: grades 1 (0 to 7.4%), 2a (22.2 to 16.6%), 2b (7.4 to 3.7%), 3 (18.5 to 27.7%), and 4 (51.8 to 44%). Conclusions. PBMP provided a rapid, inexpensive, simple, effective, and safe method of treating PB. PMID:26347811

  16. Correlation Between Stereoacuity and Experimentally Induced Graded Monocular and Binocular Astigmatism

    PubMed Central

    Puthran, Neelam; Gagal, Bhavna

    2016-01-01

    Introduction Stereopsis, the highest grade of binocular single vision, is affected by various factors, such as mis-alignment of visual axes, refractive errors especially anisometropia and astigmatism, both of which may result in amblyopia. There are very few studies in literature regarding the relationship between stereoacuity and refractive errors, especially astigmatism. Aim The present study was conducted to determine the correlation between stereoacuity and experimentally induced graded astigmatism in emmetropes. Materials and Methods A randomized study was conducted on 2000 individuals of either gender, between the ages of 8-35 years, at tertiary care centre attached to a medical college during the period of August 2012 to August 2014, All subjects were emmetropic with normal binocular single vision. Participants were randomly divided into four groups of 500 individuals each. Two groups were subjected to induced myopic astigmatism, either uni-ocularly or binocularly, using + 1.0 D and + 2.0 D cylinders at varying axes i.e., 450, 900 and 1800. Similarily, the remaining two groups were subjected to induced hypermetropic astigmatism, using - 1.0 D and - 2.0D cylinders at varying axes i.e. 450, 900 and 1800. Near stereoacuity was determined by the Titmus Fly Stereo Test, both before and after induction of astigmatism. Statistical analysis was done using paired t-test and ANOVA. Results The mean stereoacuity in emmetropes was 28.81±4.97 seconds of arc. There was a decrease in stereoacuity with increase in dioptric power of astigmatism (p<0.001). Oblique astigmatism reduced the stereoacuity maximally, while stereoacuity was least affected at 180o axis. Hypermetropic astigmatism caused more deterioration in stereoacuity than myopic astigmatism. A gross reduction in stereoacuity was noted in induced monocular astigmatism as against binocular astigmatism. Conclusion This study suggests that stereoacuity is significantly affected by even minor degrees of monocular or

  17. Occurrence of Potentially Pathogenic Bacterial-Endosymbionts in Acanthamoeba Spp.

    PubMed Central

    NIYYATI, Maryam; MAFI, Mahyar; HAGHIGHI, Ali; HAKEMI VALA, Mojdeh

    2015-01-01

    Background: Acanthamoeba- bacteria interactions enable pathogenic bacteria to tolerate harsh conditions and lead to transmission to the susceptible host. The present study was aimed to address the presence of bacterial endosymbionts of Acanthamoeba isolated from recreational water sources of Tehran, Iran. To the best of our knowledge this is the first study regarding occurrence of bacteria in environmental Acanthamoeba spp. in Iran. Methods: A total of 75 samples of recreational water sources were collected. Samples were cultured on non- nutrient agar 1.5% plates. Positive Acanthamoeba spp. were axenically grown. DNA extraction and PCR reaction was performed using JDP1-2 primers. All positive samples of Acanthamoeba were examined for the presence of endosymbionts using staining and molecular methods. The PCR products were then sequenced in order to determine the genotypes of Acanthamoeba and bacteria genera. Results: Out of 75 samples, 16 (21.3%) plates were positive for Acanthamoeba according to the morphological criteria. Molecular analysis revealed that Acanthamoeba belonged to T4 and T5 genotypes. Five isolates (35.7%) were positive for bacterial endosymbionts using staining method and PCR test. Sequencing of PCR products confirmed the presence of Pseudomonas aeruginosa and Agrobacterium tumefasiens. Conclusion: The presence of Acanthamoeba bearing pathogenic endosymbionts in water sources leads us to public health issues including improved sanitation and decontamination measures in recreational water sources in order to prevent amoebae-related infection. To the best of our knowledge this is the first report regarding the isolation of A. tumefasiens from Acanthamoeba in Iran and worldwide. PMID:26246815

  18. [Results of refractive surgery in hyperopic and combined astigmatism].

    PubMed

    Vlaicu, Valeria

    2013-01-01

    The refractive surgery includes a lot of procedures for changing the refraction of the eye to obtain a better visual acuity with no glasses or contact lenses. LASIK is the most commonly performed laser refractive surgery today. The goal is to present the postoperative evolution of the refraction and visual acuity after LASIK for Mixed and Hyperopic Astigmatism. The results show that LASIK is safe and predictible if we have well performed interventions and well-selected patients.

  19. High-resolution OCT balloon imaging catheter with astigmatism correction

    PubMed Central

    Xi, Jiefeng; Huo, Li; Wu, Yicong; Cobb, Michael J.; Hwang, Joo Ha; Li, Xingde

    2014-01-01

    We report new optics designs for an optical coherence tomography (OCT) balloon imaging catheter to achieve diffraction-limited high resolution at a large working distance and enable the correction of severe astigmatism in the catheter. The designs employed a 1 mm diameter gradient-index lens of a properly chosen pitch number and a glass rod spacer to fully utilize the available NA of the miniature optics. Astigmatism caused by the balloon tubing was analyzed, and a method based on a cylindrical reflector was proposed and demonstrated to compensate the astigmatism. A catheter based on the new designs was successfully developed with a measured diffraction-limited lateral resolution of ∼21 μm, a working distance of ∼ 11 –12 mm, and a round-shape beam profile. The performance of the OCT balloon catheter was demonstrated by 3D full-circumferential imaging of a swine esophagus in vivo along with a high-speed, Fourier-domain, mode-locked swept-source OCT system. PMID:19571960

  20. Excimer laser surgery for myopia and myopic astigmatism.

    PubMed

    Hadden, O B; Morris, A T; Ring, C P

    1995-08-01

    Photorefractive keratectomy using the Summit Excimer Laser has been carried out on 1333 eyes with myopia or myopic astigmatism which have been followed up for six months or longer. Of those, 607 have been followed up for one year. Of the eyes with myopia or myopic astigmatism of up to 3 dioptres spherical equivalent, at one year 85.6% had unaided vision of 6/6, 97.2% 6/9 or better, and 99.4% 6/12 or better. Of the eyes between -3.25 and -6.00 dioptres spherical equivalent at one year 72.1% achieved 6/6 vision unaided, 88.8% 6/9 or better, and 94.2% 6/12 or better. Of the eyes between -6.25 and -10.00 dioptres, at one year 49.6% achieved 6/6 vision unaided, 76.1% 6/9 or better and 88.0% 6/12 or better. To achieve these figures, 28% of the patients had astigmatic keratotomy, either two or three weeks before photorefractive keratectomy, or at the same time as photorefractive keratectomy. Photorefractive keratectomy is as predictable as radial keratotomy in eyes of under 6 dioptres myopia, but is more predictable than radial keratotomy in higher myopia. Photorefractive keratectomy has the advantages of leaving an eye which is structurally sound, and without diurnal variation of focusing. PMID:8534441

  1. Alignment of two mirror astronomical telescopes (the astigmatic component)

    NASA Astrophysics Data System (ADS)

    Schmid, Tobias; Thompson, Kevin; Rolland, Jannick

    2008-07-01

    The effects of alignment perturbations on the aberration fields of two mirror astronomical telescopes are discussed. It is demonstrated that expressions describing alignment induced field-linear astigmatism, published by McLeod based on the work of Schroeder, can be obtained using nodal aberration theory. Rather than merely providing a different derivation for alignment induced astigmatism, it is shown that nodal theory can provide several insights that are significant for the development of effective alignment techniques. In the example of a specific telescope sited on Mt. Hopkins (Ritchey- Chretien), two approaches to identify misalignments of the secondary mirror are demonstrated. One approach utilizes the eccentricity of defocused star images and their orientation angles to calculate the misalignment of the secondary mirror after axial coma is removed. A second approach based on the location of the two zeros of the astigmatic aberration field is then shown to give equivalent results, but at the same time ensuring a complete model of all possible effects of misalignment on the performance of the telescope.

  2. Astigmatism after a large scleral pocket incision in extracapsular cataract extraction.

    PubMed

    Lemagne, J M; Kallay, O

    1993-09-01

    In this four-month prospective study, we measured astigmatism in 116 patients who had extracapsular cataract extraction through a 13 mm scleral pocket incision. In one group, the wound was closed with five radial 10-0 polypropylene sutures. Early and late postoperative astigmatism in this group was approximately 2 diopters (D), but a significant shift to against-the-rule astigmatism occurred. In a second group, an additional 10-0 polypropylene horizontal suture was placed anteriorly to the radial suture at the 12 o'clock meridian. This reduced the against-the-rule astigmatic decay. Moreover, this group had less postoperative astigmatism. Mean corneal astigmatism was 2.27 D at one week, 1.76 D at one month, 1.37 D at two months, and 1.70 D at four months. In neither group was cutting the sutures necessary. PMID:8229717

  3. Astigmatism-corrected Czerny-Turner imaging spectrometer for broadband spectral simultaneity

    SciTech Connect

    Xue Qingsheng

    2011-04-01

    A low-cost, broadband, astigmatism-corrected Czerny-Turner arrangement with a fixed plane grating is proposed. A wedge cylindrical lens is used to correct astigmatism over a broadband spectral range. The principle and method of astigmatism correction are described in detail. We compare the performance of this modified Czerny-Turner arrangement with that of the traditional Czerny-Turner arrangement by using a practical Czerny-Turner imaging spectrometer example.

  4. Transverse-mode astigmatism in a diode-pumped unstable resonator Nd:YVO(4) laser.

    PubMed

    Cheng, Y J; Fanning, C G; Siegman, A E

    1997-02-20

    We have observed a sizable astigmatism in the output beam from a diode-pumped unstable resonator Nd:YVO(4) laser operating in a single polarization and a single-longitudinal and transverse mode. The anisotropic index of refraction of the vanadate crystal has been identified as the source of this astigmatism. A theoretical prediction of the eigenmode astigmatism based on this index anisotropy is consistent with our experimental measurements. PMID:18250780

  5. An update on Acanthamoeba keratitis: diagnosis, pathogenesis and treatment

    PubMed Central

    Lorenzo-Morales, Jacob; Khan, Naveed A.; Walochnik, Julia

    2015-01-01

    Free-living amoebae of the genus Acanthamoeba are causal agents of a severe sight-threatening infection of the cornea known as Acanthamoeba keratitis. Moreover, the number of reported cases worldwide is increasing year after year, mostly in contact lens wearers, although cases have also been reported in non-contact lens wearers. Interestingly, Acanthamoeba keratitis has remained significant, despite our advances in antimicrobial chemotherapy and supportive care. In part, this is due to an incomplete understanding of the pathogenesis and pathophysiology of the disease, diagnostic delays and problems associated with chemotherapeutic interventions. In view of the devastating nature of this disease, here we present our current understanding of Acanthamoeba keratitis and molecular mechanisms associated with the disease, as well as virulence traits of Acanthamoeba that may be potential targets for improved diagnosis, therapeutic interventions and/or for the development of preventative measures. Novel molecular approaches such as proteomics, RNAi and a consensus in the diagnostic approaches for a suspected case of Acanthamoeba keratitis are proposed and reviewed based on data which have been compiled after years of working on this amoebic organism using many different techniques and listening to many experts in this field at conferences, workshops and international meetings. Altogether, this review may serve as the milestone for developing an effective solution for the prevention, control and treatment of Acanthamoeba infections. PMID:25687209

  6. An update on Acanthamoeba keratitis: diagnosis, pathogenesis and treatment.

    PubMed

    Lorenzo-Morales, Jacob; Khan, Naveed A; Walochnik, Julia

    2015-01-01

    Free-living amoebae of the genus Acanthamoeba are causal agents of a severe sight-threatening infection of the cornea known as Acanthamoeba keratitis. Moreover, the number of reported cases worldwide is increasing year after year, mostly in contact lens wearers, although cases have also been reported in non-contact lens wearers. Interestingly, Acanthamoeba keratitis has remained significant, despite our advances in antimicrobial chemotherapy and supportive care. In part, this is due to an incomplete understanding of the pathogenesis and pathophysiology of the disease, diagnostic delays and problems associated with chemotherapeutic interventions. In view of the devastating nature of this disease, here we present our current understanding of Acanthamoeba keratitis and molecular mechanisms associated with the disease, as well as virulence traits of Acanthamoeba that may be potential targets for improved diagnosis, therapeutic interventions and/or for the development of preventative measures. Novel molecular approaches such as proteomics, RNAi and a consensus in the diagnostic approaches for a suspected case of Acanthamoeba keratitis are proposed and reviewed based on data which have been compiled after years of working on this amoebic organism using many different techniques and listening to many experts in this field at conferences, workshops and international meetings. Altogether, this review may serve as the milestone for developing an effective solution for the prevention, control and treatment of Acanthamoeba infections.

  7. Diversity and seasonal impact of Acanthamoeba species in a subtropical rivershed.

    PubMed

    Kao, Po-Min; Chou, Ming-Yuan; Tao, Chi-Wei; Huang, Wen-Chien; Hsu, Bing-Mu; Shen, Shu-Min; Fan, Cheng-Wei; Chiu, Yi-Chou

    2013-01-01

    This study evaluated the presence of Acanthamoeba species in the Puzih River watershed, which features typical subtropical monsoon climate and is located just above the Tropic of Cancer in Taiwan. The relationship between the seasonal and geographical distributions of Acanthamoeba species in this rivershed was also investigated. Acanthamoeba species were detected in water samples using the amoebal enrichment culture method and confirmed by PCR. A total of 136 water samples were included in this study, 16 (11.7%) of which contained Acanthamoeba species. Samples with the highest percentage of Acanthamoeba (32.4%) were obtained during the summer season, mainly from upstream areas. The identified species in the four seasons included Acanthamoeba palestinensis (T2), Acanthamoeba sp. IS2/T4 (T4), Acanthamoeba lenticulata (T5), Acanthamoeba hatchetti (T11), Acanthamoeba healyi (T12), and Acanthamoeba jacobsi (T15). The most frequently identified Acanthamoeba genotype was T4 (68.7%). Acanthamoeba genotype T4 is responsible for Acanthamoeba keratitis and should be considered for associated human health risk potential in the rivershed.

  8. Diversity and Seasonal Impact of Acanthamoeba Species in a Subtropical Rivershed

    PubMed Central

    Kao, Po-Min; Chou, Ming-Yuan; Tao, Chi-Wei; Huang, Wen-Chien; Hsu, Bing-Mu; Shen, Shu-Min; Fan, Cheng-Wei; Chiu, Yi-Chou

    2013-01-01

    This study evaluated the presence of Acanthamoeba species in the Puzih River watershed, which features typical subtropical monsoon climate and is located just above the Tropic of Cancer in Taiwan. The relationship between the seasonal and geographical distributions of Acanthamoeba species in this rivershed was also investigated. Acanthamoeba species were detected in water samples using the amoebal enrichment culture method and confirmed by PCR. A total of 136 water samples were included in this study, 16 (11.7%) of which contained Acanthamoeba species. Samples with the highest percentage of Acanthamoeba (32.4%) were obtained during the summer season, mainly from upstream areas. The identified species in the four seasons included Acanthamoeba palestinensis (T2), Acanthamoeba sp. IS2/T4 (T4), Acanthamoeba lenticulata (T5), Acanthamoeba hatchetti (T11), Acanthamoeba healyi (T12), and Acanthamoeba jacobsi (T15). The most frequently identified Acanthamoeba genotype was T4 (68.7%). Acanthamoeba genotype T4 is responsible for Acanthamoeba keratitis and should be considered for associated human health risk potential in the rivershed. PMID:24490160

  9. [Acanthamoeba spp. as opportunistic pathogens parasites].

    PubMed

    Castrillón, Juan C; Orozco, Lina P

    2013-04-01

    Among free-living amoeba in nature, species of the genus Acanthamoeba have been associated with human disease. These amoeba are among the most abundant protozoa in nature due to its cosmopolitan distribution and are able to survive in a wide variety of habitats because its low demand for food and in harsh environments by forming structures known as cysts. However, ecological changes and incursion of its different habitats have made this organism can invade a host and live as parasites within him. That's why this type of protozoa are known as amphizoic organism, because human can be constituted as its host, causing infections in the central nervous system, disseminated infections in skin and lungs, and keratitis. Thus, since an increase in the number of cases of Acanthamoeba infections has occurred worldwide, these protozoa have become increasingly important as agents of human disease. This review summarizes what is known of this kind of free-living amoeba, focusing on the biology, ecology, pathogenesis, diagnosis, treatment and human defense mechanism against infection by the amoeba.

  10. Gene discovery in the Acanthamoeba castellanii genome

    SciTech Connect

    Anderson, Iain J.; Watkins, Russell F.; Samuelson, John; Spencer,David F.; Majoros, William H.; Gray, Michael W.; Loftus, Brendan J.

    2005-08-01

    Acanthamoeba castellanii is a free-living amoeba found in soil, freshwater, and marine environments and an important predator of bacteria. Acanthamoeba castellanii is also an opportunistic pathogen of clinical interest, responsible for several distinct diseases in humans. In order to provide a genomic platform for the study of this ubiquitous and important protist, we generated a sequence survey of approximately 0.5 x coverage of the genome. The data predict that A. castellanii exhibits a greater biosynthetic capacity than the free-living Dictyostelium discoideum and the parasite Entamoeba histolytica, providing an explanation for the ability of A. castellanii to inhabit adversity of environments. Alginate lyase may provide access to bacteria within biofilms by breaking down the biofilm matrix, and polyhydroxybutyrate depolymerase may facilitate utilization of the bacterial storage compound polyhydroxybutyrate as a food source. Enzymes for the synthesis and breakdown of cellulose were identified, and they likely participate in encystation and excystation as in D. discoideum. Trehalose-6-phosphate synthase is present, suggesting that trehalose plays a role in stress adaptation. Detection and response to a number of stress conditions is likely accomplished with a large set of signal transduction histidine kinases and a set of putative receptorserine/threonine kinases similar to those found in E. histolytica. Serine, cysteine and metalloproteases were identified, some of which are likely involved in pathogenicity.

  11. [Acanthamoeba spp. as opportunistic pathogens parasites].

    PubMed

    Castrillón, Juan C; Orozco, Lina P

    2013-04-01

    Among free-living amoeba in nature, species of the genus Acanthamoeba have been associated with human disease. These amoeba are among the most abundant protozoa in nature due to its cosmopolitan distribution and are able to survive in a wide variety of habitats because its low demand for food and in harsh environments by forming structures known as cysts. However, ecological changes and incursion of its different habitats have made this organism can invade a host and live as parasites within him. That's why this type of protozoa are known as amphizoic organism, because human can be constituted as its host, causing infections in the central nervous system, disseminated infections in skin and lungs, and keratitis. Thus, since an increase in the number of cases of Acanthamoeba infections has occurred worldwide, these protozoa have become increasingly important as agents of human disease. This review summarizes what is known of this kind of free-living amoeba, focusing on the biology, ecology, pathogenesis, diagnosis, treatment and human defense mechanism against infection by the amoeba. PMID:23677153

  12. Finite element simulation of arcuates for astigmatism correction.

    PubMed

    Lanchares, Elena; Calvo, Begoña; Cristóbal, José A; Doblaré, Manuel

    2008-01-01

    In order to simulate the corneal incisions used to correct astigmatism, a three-dimensional finite element model was generated from a simplified geometry of the anterior half of the ocular globe. A hyperelastic constitutive behavior was assumed for cornea, limbus and sclera, which are collagenous materials with a fiber structure. Due to the preferred orientations of the collagen fibrils, corneal and limbal tissues were considered anisotropic, whereas the sclera was simplified to an isotropic one assuming that fibrils are randomly disposed. The reference configuration, which includes the initial strain distribution that balances the intraocular pressure, is obtained by an iterative process. Then the incisions are simulated. The final positions of the nodes belonging to the incised meridian and to the perpendicular one are fitted by both radii of curvature, which are used to calculate the optical power. The simulated incisions were those specified by Lindstrom's nomogram [Chu, Y., Hardten, D., Lindquist, T., Lindstrom, R., 2005. Astigmatic keratotomy. Duane's Ophthalmology. Lippincott Williams and Wilkins, Philadelphia] to achieve 1.5, 2.25, 3.0, 4.5 and 6.0D of astigmatic change, using the next values for the parameters: length of 45 degrees , 60 degrees and 90 degrees , an optical zone of 6mm, single or paired incisions. The model gives results similar to those in Lindstrom's nomogram [Chu et al., 2005] and can be considered a useful tool to plan and simulate refractive surgery by predicting the outcomes of different sorts of incisions and to optimize the values for the parameters involved: depth, length, position. PMID:18177656

  13. Advances in the Diagnosis and Treatment of Acanthamoeba Keratitis

    PubMed Central

    Clarke, Benjamin; Sinha, Arti; Parmar, Dipak N.

    2012-01-01

    This paper aims to review the recent literature describing Acanthamoeba keratitis and outline current thoughts on pathogenesis, diagnosis, and treatment as well as currently emerging diagnostic and treatment modalities. PMID:23304449

  14. Raman Microspectroscopy Analysis in the Treatment of Acanthamoeba Keratitis

    PubMed Central

    Rusciano, Giulia; Capriglione, Paola; Pesce, Giuseppe; Del Prete, Salvatore; Cennamo, Gilda; Di Cave, David; Cerulli, Luciano; Sasso, Antonio

    2013-01-01

    Acanthamoeba keratitis is a rare but serious corneal disease, often observed in contact lens wearers. Clinical treatment of infected patients frequently involves the use of polyhexamethylene biguanide (PHMB), a polymer used as a disinfectant and antiseptic, which is toxic also for the epithelial cells of the cornea. Prompt and effective diagnostic tools are hence highly desiderable for both starting early therapy and timely suspension of the treatment. In this work we use Raman microspectroscopy to analyse in vitro a single Acanthamoeba cell in cystic phase. In particular, we investigate the effect of PHMB at the single-cell level, providing useful information on both the underlying biochemical mechanism and the time frame for Acanthamoeba eradication in ocular infections. Furthermore, we demonstrate that Raman spectroscopy, in conjunction with standard multivariate analysis methods, allows discriminating between live and dead Acanthamoebas, which is fundamental to optimizing patients’ treatment. PMID:23977228

  15. Acanthamoeba encephalitis: A Case Report and Review of Therapy

    PubMed Central

    Zamora, A.; Henderson, H.; Swiatlo, E.

    2014-01-01

    Background: Acanthamoeba is a rare cause of encephalitis yet is associated with high mortality. Treatment protocols vary greatly and generally include combination therapy across a wide spectrum of antiinfective classes. Case Description: A 63-year-old male who underwent renal transplantation presented 6 months after transplantation with depressed level of consciousness. Imaging of the head with computerized tomography showed an enhancing lesion suspicious for brain abscess. Biopsy of the lesion showed Acanthamoeba cysts. The patient was treated with sulfadiazine, fluconazole, flucytosine, azithromycin, and miltefosine but without success. We review recently published cases of Acanthamoeba encephalitis with an emphasis on treatment protocols and outcomes. Conclusion: Free-living protozoans such as Acanthamoeba are ubiquitous in the environment and should be suspected in immunosuppressed persons who present with central nervous system findings and brain abscess. Biopsy is critical to establish the etiology so that appropriate combination therapy can be deployed. PMID:24991471

  16. Propagation of the Lissajous singularity dipole through an astigmatic lens

    NASA Astrophysics Data System (ADS)

    Chen, Haitao; Gao, Zenghui; Zou, Xuefang; Huang, Weigang; Wang, Fanhou

    2013-11-01

    The propagation was investigated of a pair of Lissajous singularities of opposite singularity index called the Lissajous singularity dipole (LSD) through an astigmatic lens. It is shown that after passing through the lens the positions of the singularities are inverted and more than two LSDs occur. Changes in the degree of polarization of the LSDs as well as in the shape of the Lissajous figures also occur. In addition, Lissajous singularities may take place at the focal plane, and a single Lissajous singularity may appear and vanish under certain conditions. The results are compared with those of previous work.

  17. Several staining techniques to enhance the visibility of Acanthamoeba cysts.

    PubMed

    El-Sayed, Nagwa Mostafa; Hikal, Wafaa Mohamed

    2015-03-01

    Acanthamoeba is one of the most common free-living amoebae. It is widespread in the environment and can infect humans causing keratitis. Delayed diagnosis or misdiagnosis leads to extensive corneal inflammation and profound visual loss. Therefore, accurate and rapid diagnosis of Acanthamoeba keratitis is essential for successful treatment and good prognosis. This study was designed to use different staining techniques to facilitate the identification of Acanthamoeba cysts. Acanthamoeba cysts were isolated by cultivation of either corneal scraping specimens or tap water samples onto non-nutrient agar plates seeded with Escherichia coli. Subcultures were done from positive cultures until unique cysts were isolated. Acanthamoeba cysts were stained temporarily using iodine, eosin, methylene blue, and calcofluor white (CFW) stains and as permanent slides after processing for mounting using modified trichrome, Gimenez and Giemsa staining. These stains were compared on the basis of staining quality including clarity of morphological details, differentiation between cytoplasm and nuclei, color and contrast, and also other characteristics of the staining techniques, including ease of handling, time taken for the procedure, and cost effectiveness. The cysts of Acanthamoeba were recognized in the form of double-walled cysts: the outer wall (ectocyst) that was being differentiated from the variably stained surrounding background and the inner wall (endocyst) that was sometimes stellated, polygonal, round, or oval and visualized as separate from the spherical, sometimes irregular, outline of the ectocyst. Regarding the temporary stains, it was found that they were efficient for visualizing the morphological details of Acanthamoeba cysts. In CFW staining, Acanthamoeba cysts appeared as bluish-white or turquoise oval halos although the internal detail was not evident. On the other hand, the results of permanent-stained slides showed the most consistent stain for identification of

  18. Several staining techniques to enhance the visibility of Acanthamoeba cysts.

    PubMed

    El-Sayed, Nagwa Mostafa; Hikal, Wafaa Mohamed

    2015-03-01

    Acanthamoeba is one of the most common free-living amoebae. It is widespread in the environment and can infect humans causing keratitis. Delayed diagnosis or misdiagnosis leads to extensive corneal inflammation and profound visual loss. Therefore, accurate and rapid diagnosis of Acanthamoeba keratitis is essential for successful treatment and good prognosis. This study was designed to use different staining techniques to facilitate the identification of Acanthamoeba cysts. Acanthamoeba cysts were isolated by cultivation of either corneal scraping specimens or tap water samples onto non-nutrient agar plates seeded with Escherichia coli. Subcultures were done from positive cultures until unique cysts were isolated. Acanthamoeba cysts were stained temporarily using iodine, eosin, methylene blue, and calcofluor white (CFW) stains and as permanent slides after processing for mounting using modified trichrome, Gimenez and Giemsa staining. These stains were compared on the basis of staining quality including clarity of morphological details, differentiation between cytoplasm and nuclei, color and contrast, and also other characteristics of the staining techniques, including ease of handling, time taken for the procedure, and cost effectiveness. The cysts of Acanthamoeba were recognized in the form of double-walled cysts: the outer wall (ectocyst) that was being differentiated from the variably stained surrounding background and the inner wall (endocyst) that was sometimes stellated, polygonal, round, or oval and visualized as separate from the spherical, sometimes irregular, outline of the ectocyst. Regarding the temporary stains, it was found that they were efficient for visualizing the morphological details of Acanthamoeba cysts. In CFW staining, Acanthamoeba cysts appeared as bluish-white or turquoise oval halos although the internal detail was not evident. On the other hand, the results of permanent-stained slides showed the most consistent stain for identification of

  19. Crescent Bodies of Parachlamydia acanthamoeba and Its Life Cycle within Acanthamoeba polyphaga: an Electron Micrograph Study

    PubMed Central

    Greub, Gilbert; Raoult, Didier

    2002-01-01

    Parachlamydiaceae are endosymbionts of free-living amoeba first identified in 1997. Two developmental stages, elementary and reticulate bodies, were observed; however, their localization and proportions according to culture condition and duration remain unknown. The life cycle of Parachlamydia acanthamoeba within Acanthamoeba polyphaga was studied by transmission electron microscopy of 8-, 36-, and 144-h coculture. Morphometry and quantification were performed using SAMBA software. The elementary body, the predominant stage within the amoebae, was located mainly within their vacuoles. The multiplication of Parachlamydia bacteria by binary fission of reticulate bodies was independently associated with culture in PYG broth (odds ratio [OR] = 4.4; 95% confidence interval [CI], 1.55 to 12.46) and with the presence of reticulate bodies within the amoebae (OR = 2.10; 95% CI, 1.53 to 2.89). A third developmental stage was observed, the crescent body. Its presence outside and inside the amoebae was associated mainly with prolonged incubation time (OR = 3.98; 95% CI, 1.49 to 10.68, and OR = 5.98; 95% CI, 1.75 to 20.4, respectively). Elementary and crescent bodies were released into the extracellular medium within vesicles or after amoebal lysis. For both, phagocytosis was their mode of entry. This electron micrograph study revealed another infective developmental stage, the crescent body, and provided quantitative analysis of the life cycle of P. acanthamoeba within A. polyphaga. PMID:12039769

  20. Demodex infections in general Polish population, in patients suffering from blepharitis, and among people who work with microscopes.

    PubMed

    Garbacewicz, Aleksandra; Udziela, Monika; Grytner-Ziecina, Barbara; Szaflik, Jacek P; Szaflik, Jerzy

    2010-01-01

    In this study we examined 264 people to estimate the prevalence of Demodex infection. The subjects were divided into 4 groups. First two groups consisted of young people (mean age 22 years) and seniors (mean age 66 years) respectively. The third group included people who work with microscopes (mean age 44 years). Forth group consisted of patients with diagnosed blepharitis (mean age 65 years). From every individual 3-4 lashes were epilated from the eyelids of both eyes and examined under the microscope for Demodex mites. The statistical analysis based on logistic regression was used to estimate the probability of infection. Age was independent variable significant for this model (p < 0.001). Significant relation between age and probability of Demodex infection was showed. The lowest number of infected individuals was observed in the group of young subjects (only 5%), the highest in the blepharitis patients (74% infected). Among microscope users 30% were infected, in the group of seniors 34% were infected.

  1. Statins and Voriconazole Induce Programmed Cell Death in Acanthamoeba castellanii

    PubMed Central

    López-Arencibia, Atteneri; Sifaoui, Ines; Reyes-Batlle, María; Valladares, Basilio; Martínez-Carretero, Enrique; Piñero, José E.; Maciver, Sutherland K.; Lorenzo-Morales, Jacob

    2015-01-01

    Members of the genus Acanthamoeba are facultative pathogens of humans, causing a sight-threatening keratitis and a life-threatening encephalitis. In order to treat those infections properly, it is necessary to target the treatment not only to the trophozoite but also to the cyst. Furthermore, it may be advantageous to avoid parasite killing by necrosis, which may induce local inflammation. We must also avoid toxicity of host tissue. Many drugs which target eukaryotes are known to induce programmed cell death (PCD), but this process is poorly characterized in Acanthamoeba. Here, we study the processes of programmed cell death in Acanthamoeba, induced by several drugs, such as statins and voriconazole. We tested atorvastatin, fluvastatin, simvastatin, and voriconazole at the 50% inhibitory concentrations (IC50s) and IC90s that we have previously established. In order to evaluate this phenomenon, we investigated the DNA fragmentation, one of the main characteristics of PCD, with quantitative and qualitative techniques. Also, the changes related to phosphatidylserine exposure on the external cell membrane and cell permeability were studied. Finally, because caspases are key to PCD pathways, caspase activity was evaluated in Acanthamoeba. All the drugs assayed in this study induced PCD in Acanthamoeba. To the best of our knowledge, this is the first study where PCD induced by drugs is described quantitatively and qualitatively in Acanthamoeba. PMID:25733513

  2. Pathogenic Acanthamoeba strains from water sources in Jamaica, West Indies.

    PubMed

    Lorenzo-Morales, J; Lindo, J F; Martinez, E; Calder, D; Figueruelo, E; Valladares, B; Ortega-Rivas, A

    2005-12-01

    In 2004, samples of tap water and of river and sea water associated with human activities were collected in Jamaica, West Indies, and checked for free-living Acanthamoeba. The morphologies of the cysts and trophozoites observed and the results of PCR-based amplifications with a genus-specific primer pair were used to identify the Acanthamoeba isolates. The potential of each isolate as a human pathogen was then evaluated using thermotolerance and osmotolerance assays and two PCR-based assays for Acanthamoeba pathogenesis. Acanthamoeba were identified in 36.1%, 26.4% and 49.6% of the tap-, river- and sea-water samples collected, respectively. Pathogenic potential was shown by 60.0% of the Acanthamoeba strains isolated from tap water, 68.4% of the strains from river water, and 40.4% of the seawater strains. Sequencing of ribosomal DNA revealed the T1, T2, T4, T5, T7, T9 and T11 genotypes. Isolates of the T4 genotype were collected from tap, rain and sea water and, as expected, exhibited the most pathogenic traits; most were osmotolerant, thermotolerant and expressing extracellular serine protease. This is the first study of the occurrence and distribution of Acanthamoeba in water in the West Indies, and the results confirm the presence of potentially pathogenic strains in Jamaica.

  3. Quasi two-dimensional astigmatic solitons in soft chiral metastructures.

    PubMed

    Laudyn, Urszula A; Jung, Paweł S; Karpierz, Mirosław A; Assanto, Gaetano

    2016-01-01

    We investigate a non-homogeneous layered structure encompassing dual spatial dispersion: continuous diffraction in one transverse dimension and discrete diffraction in the orthogonal one. Such dual diffraction can be balanced out by one and the same nonlinear response, giving rise to light self-confinement into astigmatic spatial solitons: self-focusing can compensate for the spreading of a bell-shaped beam, leading to quasi-2D solitary wavepackets which result from 1D transverse self-localization combined with a discrete soliton. We demonstrate such intensity-dependent beam trapping in chiral soft matter, exhibiting one-dimensional discrete diffraction along the helical axis and one-dimensional continuous diffraction in the orthogonal plane. In nematic liquid crystals with suitable birefringence and chiral arrangement, the reorientational nonlinearity is shown to support bell-shaped solitary waves with simple astigmatism dependent on the medium birefringence as well as on the dual diffraction of the input wavepacket. The observations are in agreement with a nonlinear nonlocal model for the all-optical response. PMID:26975651

  4. Isolation of Acanthamoeba from the rhizosphere of maize and lucerne plants

    NASA Astrophysics Data System (ADS)

    Orosz, Erika; Farkas, Ágnes; Ködöböcz, László; Becsak, Péter; Danka, József; Kucsera, István; Füleky, György

    2013-04-01

    Acanthamoeba species are free-living amoebae that can be found in almost every range of environments. Within this genus, a number of species are recognized as human pathogens, potentially causing Acanthamoeba keratitis, granulomatous amoebic encephalitis, and chronic granulomatous lesions. Soil and water samples were taken from experimental station at Julianna Major of Plant Protection Institute of Centre for Agricultural Research, Hungarian Academy of Sciences. We detected living Acanthamoeba spp. based on culture- confirmed detection combined with the molecular taxonomic identification method. Living Acanthamoeba spp. were detected in thirteen (65%) samples. The presence of Acanthamoeba spp. in the samples depends significantly on the rhizosphere plants. The most frequently identified living Acanthamoeba genotype was T4 followed by T11, T2/T6 and T17. Genotypes T4 and T11 of Acanthamoeba, are responsible for Acanthamoeba keratitis as well as granulomatous amoebic encephalitis, and should therefore be considered as a potential health risk associated with human activities in the environment.

  5. Fatal Acanthamoeba Encephalitis in a Patient With a Total Artificial Heart (Syncardia) Device

    PubMed Central

    Tan, Susanna K.; Gajurel, Kiran; Tung, Christie; Albers, Gregory; Deresinski, Stan; Montoya, Jose G.; Sheikh, Ahmad Y.; Banerjee, Dipanjan; Ha, Richard

    2014-01-01

    Acanthamoeba encephalitis is an uncommon but often fatal infection complication. Here we report the first case of Acanthamoeba encephalitis in a patient with a Total Artificial Heart device. PMID:25734127

  6. identification of Pseudomonas spp. as amoeba-resistant microorganisms in isolates of Acanthamoeba.

    PubMed

    José Maschio, Vinicius; Corção, Gertrudes; Rott, Marilise Brittes

    2015-01-01

    Acanthamoeba is a "Trojan horse" of the microbial world. The aim of this study was to identify the presence of Pseudomonas as an amoeba-resistant microorganism in 12 isolates of Acanthamoeba. All isolates showed the genus Pseudomonas spp. as amoeba-resistant microorganisms. Thus, one can see that the Acanthamoeba isolates studied are hosts of Pseudomonas.

  7. IDENTIFICATION OF Pseudomonas spp. AS AMOEBA-RESISTANT MICROORGANISMS IN ISOLATES OF Acanthamoeba

    PubMed Central

    Maschio, Vinicius José; Corção, Gertrudes; Rott, Marilise Brittes

    2015-01-01

    Acanthamoeba is a “Trojan horse” of the microbial world. The aim of this study was to identify the presence of Pseudomonas as an amoeba-resistant microorganism in 12 isolates of Acanthamoeba. All isolates showed the genus Pseudomonas spp. as amoeba-resistant microorganisms. Thus, one can see that the Acanthamoeba isolates studied are hosts of Pseudomonas. PMID:25651331

  8. Accuracy of the Spot and Plusoptix photoscreeners for detection of astigmatism

    PubMed Central

    Crescioni, Mabel; Miller, Joseph M.; Harvey, Erin M.

    2015-01-01

    Purpose To evaluate the accuracy of the Spot (V2.0.16) and Plusoptix S12 (ROC4, V6.1.4.0) photoscreeners in detecting astigmatism meeting AAPOS referral criteria in students from a population with high prevalence of astigmatism. Methods Students attending grades 3–8 on the Tohono O’odham reservation were examined. Screening was attempted with both the Spot and Plusoptix photoscreeners. Results were compared to cycloplegic refraction. Screening attempts providing no estimate of refractive error were considered fail/refer. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for detection of refractive errors were determined using AAPOS referral criteria and receiver operating characteristic area under the curve (ROC AUC) analysis was conducted for measures of astigmatism. Agreement between screening and cycloplegic refraction measurements of astigmatism, spherical equivalent, and anisometropia were assessed using t tests and correlation analyses. Results A total of 209 students were included. Of the total, 116 (55%) met examination-positive criteria based on cycloplegic refraction, with 105 of those (90%) meeting the criterion for astigmatism. Measurements success rates were 97% for Spot and 54% for Plusoptix. Comparing the Spot and the Plusoptix, sensitivity was 96% versus 100%, specificity was 87% versus 61%, PPV was 90% versus 76%, and NPV was 94% versus 100% for detection of refractive error. Both screeners overestimated astigmatism by 1/3 D to 2/3 D. AUC for astigmatism was 0.97 for Spot and 0.83 for Plusoptix. Conclusions In this highly astigmatic population, the Spot and the Plusoptix had similar sensitivity, but the Spot had better specificity and measurement success rates. Compared with results from study samples with lower rates of astigmatism, our results highlight the need to assess the ability of screening instruments to detect individual types of refractive errors. PMID:26486025

  9. [Now soft toric contact lenses; silicone hydrogel lens for astigmatism].

    PubMed

    Radu, Simona

    2006-01-01

    Soft toric contact lenses are a good alternative for the optical correction of astigmatism. They provide a wide visual field, quick adaptation process, negligible aniseikonia, together with enhanced comfort and reduced incidence of complications introduced by the lenses for frequent replacement. Still practitioners do not recommend them proactively and the satisfaction obtained by the patients is not high enough. This paper presents two recent studies that investigate the opinions of specialists and contact lens wearers and introduce a new contact lens, with an original design, born after 30 years of domination of only 2 modalities of rotational stabilization: prism ballast and dual thin zones. The lens is manufactured using a silicon-hydrogel material of 2-nd generation that provides sustained comfort and better oxygenation. PMID:16773940

  10. Experimental validation of a novel imaging scheme to eliminate astigmatism

    NASA Astrophysics Data System (ADS)

    Fierroz, S.; Bitter, M.; Delgado-Aparicio, L.; Hill, K. W.; Pablant, N.; Scott, S.; Scotti, F.; Rice, J. E.

    2010-11-01

    Recent papers by Bitter et al.^1-3 have proposed novel imaging schemes to eliminate astigmatism by matched pairs of spherically bent crystals or reflectors. These imaging schemes should allow stigmatic (or point-to point) imaging at arbitrarily large angles of incidence and be applicable to a broad spectrum of the electromagnetic radiation, including microwaves, visible light, EUV radiation, and x-rays, if appropriate spherically bent reflectors are used. This paper presents experimental results from tests of one of these imaging schemes with visible light, which validate the concept of this scheme and show that stigmatic imaging of objects with areas of about 5 mm x 5 mm is possible. ^1M. Bitter et al, Rev Sci. Instrum. 79, 10E927 (2008); ^2M. Bitter et al., J. Xray Sci. Technol. 17, 153 (2009); ^3M. Bitter et al., J. Phys. B: At. Mol. Opt. Phys. 43, 144011 (2010)

  11. Cytotoxic activity of N-chlorotaurine on Acanthamoeba spp.

    PubMed

    Fürnkranz, Ursula; Nagl, Markus; Gottardi, Waldemar; Köhsler, Martina; Aspöck, Horst; Walochnik, Julia

    2008-02-01

    Acanthamoeba spp. are the causative agents of Acanthamoeba keratitis (AK), which mainly occurs in contact lens wearers, and of skin lesions, granulomatous amoebic encephalitis (GAE), and disseminating diseases in the immunocompromised host. AK therapy is complex and irritating for the eye, skin lesions are difficult to treat, and there is no effective treatment for GAE. Therefore, new anti-Acanthamoeba drugs are needed. We investigated the anti-Acanthamoeba activity of N-chlorotaurine (NCT), an endogenous mild antiseptic. It was shown that NCT has amoebicidal qualities, both in phosphate-buffered saline (PBS) and in amoebic culture medium. After 6 h of treatment with 10 mM NCT in PBS, the levels of trophozoites of all strains investigated already showed at least a 2-log reduction. When the trophozoites were treated with 20 mM NCT in culture medium, they showed a 2-log reduction after 24 h. The addition of NH(4)Cl to NCT led to a faster decrease in the numbers of living cells, if tests were carried out in PBS. A delay of excystation was observed when cysts were treated with 55 mM (1%) NCT in culture medium. A complete failure of excystment was the result of treatment with 1% NCT plus 1% NH(4)Cl in PBS. Altogether, NCT clearly demonstrated amoebicidal activity at concentrations well tolerated by human tissues and might be useful as a topical drug for the treatment of Acanthamoeba infections. The addition of ammonium chloride can be considered to enhance the activity.

  12. Protein profiles and immunoreactivities of Acanthamoeba morphological groups and genotypes.

    PubMed

    Pumidonming, Wilawan; Koehsler, Martina; Leitsch, David; Walochnik, Julia

    2014-11-01

    Acanthamoeba is a free-living protozoan found in a wide variety of habitats. A classification of Acanthamoeba into currently eighteen genotypes (T1-T18) has been established, however, data on differences between genotypes on the protein level are scarce. The aim of this study was to compare protein and immunoreactivity profiles of Acanthamoeba genotypes. Thirteen strains, both clinical and non-clinical, from genotypes T4, T5, T6, T7, T9, T11 and T12, representing three morphological groups, were investigated for their protein profiles and IgG, IgM and IgA immunoreactivities. It was shown that protein and immunoreactivity profiles of Acanthamoeba genotypes T4, T5, T6, T7, T9, T11 and T12 are clearly distinct from each other, but the banding patterns correlate to the morphological groups. Normal human sera revealed anti-Acanthamoeba antibodies against isolates of all investigated genotypes, interestingly, however only very weak IgM and virtually no IgA immunoreactivity with T7 and T9, both representing morphological group I. The strongest IgG, IgM and IgA immunoreactivities were observed for genotypes T4, T5 and T6. Differences of both, protein and immunological patterns, between cytopathic and non-cytopathic strains, particularly within genotype T4, were not at the level of banding patterns, but rather in expression levels.

  13. Risk Factors for Astigmatism in the Vision in Preschoolers (VIP) Study

    PubMed Central

    Huang, Jiayan; Maguire, Maureen G.; Ciner, Elise; Kulp, Marjean Taylor; Cyert, Lynn A.; Quinn, Graham E.; Orel-Bixler, Deborah; Moore, Bruce; Ying, Gui-Shuang

    2014-01-01

    Purpose To determine demographic and refractive risk factors for astigmatism in the Vision in Preschoolers (VIP) Study. Methods Three- to 5-year old Head Start preschoolers (N=4,040) from 5 clinical centers underwent comprehensive eye examinations by study-certified optometrists and ophthalmologists, including monocular visual acuity (VA) testing, cover testing, and cycloplegic retinoscopy. Astigmatism was defined as the presence of ≥ +1.5 diopters (D) cylinder in either eye, measured with cycloplegic refraction. The associations of risk factors with astigmatism were evaluated using the odds ratio (OR) and its 95% confidence intervals (95% CI) from logistic regression models. Results Among 4,040 VIP Study participants over-representing children with vision disorders, 687 (17%) had astigmatism, and majority of astigmatism was with-the-rule (83.8%). In multivariate analyses, African-American (OR=1.65, 95% CI: 1.22–2.24), Hispanic (OR=2.25, 95% CI: 1.62–3.12) and Asian children (OR=1.76, 95% CI: 1.06–2.93) were more likely to have astigmatism compared with non-Hispanic white children, while American Indian children were less likely to have astigmatism than Hispanic, African American and Asian children (P<0.0001). Refractive error was associated with astigmatism in a non-linear manner, with an OR of 4.50 (95% CI: 3.00 – 6.76) for myopia (≤ −1.0D in spherical equivalent), and 1.55 (95% CI: 1.29 –1.86) for hyperopia (≥ +2.0D) when compared to children without refractive error (> −1.0D, < +2.0D). There was a trend of an increasing percentage of astigmatism among older children (linear trend p=0.06). The analysis for risk factors of with-the-rule astigmatism provided similar results. Conclusions Among Head Start preschoolers, Hispanic ethnicity, African-American and Asian race, myopic and hyperopic refractive error were associated with an increased risk of astigmatism, consistent with findings from the population-based Multi-ethnic Pediatric Eye Disease

  14. Genetic diversity of Acanthamoeba isolates from ocean sediments

    PubMed Central

    Liu, Hua; Ha, Young-Ran; Lee, Sung-Tae; Hong, Yean-Chul; Kong, Hyun-Hee

    2006-01-01

    Genetic diversity of 18 Acanthamoeba isolates from ocean sediments was evaluated by comparing mitochondrial (mt) DNA RFLP, 18S rDNA sequences and by examining their cytopathic effects on human corneal epithelial cells versus reference strains. All isolates belonged to morphologic group II. Total of 16 restriction phenotypes of mtDNA from 18 isolates demonstrated the genetic diversity of Acanthamoeba in ocean sediments. Phylogenetic analysis using 18s rDNA sequences revealed that the 18 isolates were distinct from morphological groups I and III. Fifteen isolates showed close relatedness with 17 clinical isolates and A. castellanii Castellani and formed a lineage equivalent to T4 genotype of Byers' group. Two reference strains from ocean sediment, A. hatchetti BH-2 and A. griffini S-7 clustered unequivocally with these 15 isolates. Diversity among isolates was also evident from their cytopathic effects on human corneal cells. This is the first time describing Acanthamoeba diversity in ocean sediments in Korea. PMID:16809959

  15. Interaction between Vibrio mimicus and Acanthamoeba castellanii

    PubMed Central

    Abd, Hadi; Valeru, Soni Priya; Sami, Susan Marouf; Saeed, Amir; Raychaudhuri, Saumya; Sandström, Gunnar

    2010-01-01

    Vibrio mimicus is a Gram-negative bacterium, which causes gastroenteritis and is closely related to Vibrio cholerae. The environmental reservoir of this bacterium is far from defined. Acanthamoeba as well as Vibrio species are found in diverse aquatic environments. The present study was aimed to investigate the ability of A. castellanii to host V. mimicus, the role of bacterial protease on interaction with A. castellanii and to disclose the ability of cysts to protect intracellular V. mimicus. Co-cultivation, viable counts, gentamicin assay, electron microscopy and statistical analysis showed that co-cultivation of wild type and luxO mutant of V. mimicus strains with A. castellanii did not inhibit growth of the amoeba. On the other hand co-cultivation enhanced growth and survival of V. mimicus strains. Vibrio mimicus showed intracellular behaviour because bacteria were found to be localized in the cytoplasm of amoeba trophozoites and remain viable for 14 days. The cysts protected intracellular V. mimicus from high level of gentamicin. The intracellular growth of V. mimicus in A. castellanii suggests a role of A. castellanii as a host for V. mimicus. PMID:20454692

  16. Acanthamoeba royreba sp. n. from a human tumor cell culture.

    PubMed

    Willaert, E; Stevens, A R; Tyndall, R L

    1978-02-01

    A new species of Acanthamoeba was isolated from a culture of an established line of human choriocarcinoma cells. The identification of this strain, originally called the Oak Ridge strain, and the establishment of a new species for it were based on morphologic, serologic, and immunochemical studies. In general, the structure of the trophozoite did not differ significantly from that of other species of Acanthamoeba, except that a body which more closely resembled a centriole than material described previously as centriolar satellites was observed in trophozoites examined with the electron microscope. The dimensions of the trophozoite were the smallest among the species of Acanthamoeba. The cyst was typical of the genus, but differed from those of other species by its smaller size and the presence of numerous ostioles. Studies of the Oak Ridge strain by immunofluorescence using antisera developed against the isolate and Acanthamoeba culbertsoni, A. castellanii, A. polyphaga, A. rhysodes, A. astronyxis, and A. palestinensis revealed the antigenic uniqueness of the Oak Ridge strain. It was demonstrated by immunoelectrophoretic analyses of the soluble proteins of the Oak Ridge strain that shared approximately 1/2 of its antigenic structure with A. castellanii and A. culbertsoni. The antigenic differences of the isolate from other species of Acanthamoeba were deduced from comparison of the antigenic constitution of these species and the Oak Ridge strain with A. culbertsoni and A. castellanii. Although the strain was initially recognized by its cytopathogenicity for cultures, it did not produce acute infections in mice after intranasal inoculation of 1 X 10(4) ameba/mouse. The foregoing results constituted the basis for the establishment of the Oak Ridge strain as a new species, A. royreba sp. n., in the genus Acanthamoeba. PMID:566323

  17. IL-17A-mediated protection against Acanthamoeba keratitis.

    PubMed

    Suryawanshi, Amol; Cao, Zhiyi; Sampson, James F; Panjwani, Noorjahan

    2015-01-15

    Acanthamoeba keratitis (AK) is a very painful and vision-impairing infection of the cornea that is difficult to treat. Although past studies have indicated a critical role of neutrophils and macrophages in AK, the relative contribution of the proinflammatory cytokine, IL-17A, that is essential for migration, activation, and function of these cells into the cornea is poorly defined. Moreover, the role of the adaptive immune response, particularly the contribution of CD4(+) T cell subsets, Th17 and regulatory T cells , in AK is yet to be understood. In this report, using a mouse corneal intrastromal injection-induced AK model, we show that Acanthamoeba infection induces a strong CD4(+) T effector and regulatory T cell response in the cornea and local draining lymph nodes. We also demonstrate that corneal Acanthamoeba infection induces IL-17A expression and that IL-17A is critical for host protection against severe AK pathology. Accordingly, IL-17A neutralization in Acanthamoeba-infected wild-type mice or Acanthamoeba infection of mice lacking IL-17A resulted in a significantly increased corneal AK pathology, increased migration of inflammatory cells at the site of inflammation, and a significant increase in the effector CD4(+) T cell response in draining lymph nodes. Thus, in sharp contrast with other corneal infections such as herpes and Pseudomonas aeruginosa keratitis where IL-17A exacerbates corneal pathology and inflammation, the findings presented in this article suggest that IL-17A production after Acanthamoeba infection plays an important role in host protection against invading parasites.

  18. Numerical simulation of astigmatic liquid lenses tuned by a stripe electrode.

    PubMed

    Lima, N C; Cavalli, A; Mishra, K; Mugele, F

    2016-02-22

    We propose a new design for tuning the astigmatism of liquid micro-lenses using electric field and hydrostatic pressure as control parameters. We explore the feasibility and operating range of the lens with a self-consistent numerical calculation of the electric field distribution and the shape of the two-phase interface. Equilibrium shapes, including surface profiles parallel and perpendicular to a stripe electrode, are extracted to determine the astigmatism. The wavefronts are decomposed into Zernike polynomials under zero defocus conditions using a commercial ray-tracing software. We observe that the global curvature of the lens is primarily controlled by the hydrostatic pressure, while asphericity and astigmatism are controlled by the electric field. For optimized electrode geometries and simultaneous control of pressure and electric fields the astigmatism can be tuned from Z6 = 0…0.38 μm with minor changes in the focal length. PMID:26907069

  19. Acanthamoeba DNA can be directly amplified from corneal scrapings.

    PubMed

    El-Sayed, Nagwa Mostafa; Younis, Mohamed Saad; Elhamshary, Azza Mohamed; Abd-Elmaboud, Amina Ibrahim; Kishik, Shereen Magdy

    2014-09-01

    This study evaluated the performance of direct amplification of Acanthamoeba-DNA bypassing DNA extraction in the diagnosis of Acanthamoeba keratitis in clinically suspected cases in comparison to direct microscopic examination and in vitro culture. Corneal scrapings were collected from 110 patients who were clinically suspected to have Acanthamoeba keratitis, 63 contact lens wearers (CLW), and 47 non-contact lens wearers (NCLW). Taken samples were subjected to direct microscopic examination, cultivation onto the non-nutrient agar plate surface seeded with Escherichia coli, and PCR amplification. The diagnostic performance of these methods was statistically compared. The results showed that Acanthamoeba infection was detected in 21 (19.1%) of clinically suspected cases (110); 17 (81%) of them were CLW and the remaining 4 (19%) positive cases were NCLW. Regarding the used diagnostic methods, it was found that direct amplification of Acanthamoeba DNA bypassing nucleic acid extraction was superior to microscopy and culture in which 21 cases (19.1%) were positive for Acanthamoeba by PCR compared to 19 positive cases by culture (17.3%) and one case (0.9%) by direct smear. The difference in detection rates between culture and direct smear was highly statistically significant (P = 0.001). On the other hand, there was no significant difference in detection rates between culture and PCR (P = 0.86). On using culture as the gold standard, PCR showed three false-positive samples that were negative by culture and one false-negative sample that was positive by culture. At the same time, direct smear showed 18 false-negative samples. The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of PCR were 94.7, 96.7, 85.7, 98.9, and 96.4, respectively, while those of direct smear were 5.3, 100, 100, 83.5, and 83.6, respectively. In conclusion, direct amplification of Acanthamoeba-DNA bypassing DNA extraction is a reliable

  20. A simple method for astigmatic compensation of folded resonator without Brewster window.

    PubMed

    Qiao, Wen; Xiaojun, Zhang; Yonggang, Wang; Liqun, Sun; Hanben, Niu

    2014-02-10

    A folded resonator requires an oblique angle of incidence on the folded curved mirror, which introduces astigmatic distortions that limit the performance of the lasers. We present a simple method to compensate the astigmatism of folded resonator without Brewster windows for the first time to the best of our knowledge. Based on the theory of the propagation and transformation of Gaussian beams, the method is both effective and reliable. Theoretical results show that the folded resonator can be compensated astigmatism completely when the following two conditions are fulfilled. Firstly, when the Gaussian beam with a determined size beam waist is obliquely incident on an off-axis concave mirror, two new Gaussian beam respectively in the tangential and sagittal planes are formed. Another off-axis concave mirror is located at another intersection point of the two new Gaussian beams. Secondly, adjusting the incident angle of the second concave mirror or its focal length can make the above two Gaussian beam coincide in the image plane of the second concave mirror, which compensates the astigmatic aberration completely. A side-pumped continues-wave (CW) passively mode locked Nd:YAG laser was taken as an example of the astigmatically compensated folded resonators. The experimental results show good agreement with the theoretical predictions. This method can be used effectively to design astigmatically compensated cavities resonator of high-performance lasers.

  1. Ocular surface discomfort and Demodex: effect of tea tree oil eyelid scrub in Demodex blepharitis.

    PubMed

    Koo, Hyun; Kim, Tae Hyung; Kim, Kyoung Woo; Wee, Sung Wook; Chun, Yeoun Sook; Kim, Jae Chan

    2012-12-01

    The purpose of this study was to evaluate the relation between ocular discomfort and ocular Demodex infestation, and therapeutic effects of tea tree oil (TTO) in Demodex blepharitis patients. Three hundred and thirty-five patients with ocular discomfort were evaluated for ocular Demodex infestation and subjective symptoms with ocular surface discomfort index (OSDI) score. Among them, Demodex-infested patients were randomized to receive either eyelid scrubbing with TTO (TTO group,106 patients) or without TTO (Control group, 54 patients) for 1 month. Demodex were found in 84% of patients with ocular discomfort. The number of Demodex was significantly correlated with age (P = 0.04) and OSDI score (P = 0.024). After eyelid scrub treatment, Demodex count was reduced from 4.0 ± 2.5 to 3.2 ± 2.3 in the TTO group (P = 0.004) and from 4.3 ± 2.7 to 4.2 ± 2.5 in the control group (P = 0.27). Also, OSDI score was reduced from 34.5 ± 10.7 to 24.1 ± 11.9 in the TTO group (P = 0.001) and from 35.3 ± 11.6 to 27.5 ± 12.8 in the control group (P = 0.04). In conclusion, Demodex number showed a significant positive correlation with age and subjective ocular discomfort. The tea tree oil eyelid scrub treatment is effective for eliminating ocular Demodex and improving subjective ocular symptoms.

  2. Colonization of broilers by Campylobacter jejuni internalized within Acanthamoeba castellanii

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We present the first report that Campylobacter jejuni, internalized within Acanthamoeba castellanii, colonized broilers. After 1, 3, 7 and 14 days post challenge none of the broilers challenged with negative controls were colonized, but were with internalized C. jejuni. The biology of protozoa-Cam...

  3. Fatal Disseminated Acanthamoeba lenticulata Acanthamebiasis in a Heart Transplant Patient

    PubMed Central

    Combes, Alain; de Jonckheere, Johan F.; Datry, Annick; Varnous, Shaïda; Martinez, Valérie; Ptacek, Sara García; Caumes, Eric; Capron, Frédérique; Francès, Camille; Gibert, Claude; Chosidow, Olivier

    2007-01-01

    We report a fatal case of disseminated acanthamebiasis caused by Acanthamoeba lenticulata (genotype T5) in a 39-year-old heart transplant recipient. The diagnosis was based on skin histopathologic results and confirmed by isolation of the ameba from involved skin and molecular analysis of a partial 18S rRNA gene sequence (DF3). PMID:17553253

  4. Isolation of Acanthamoeba culbertsoni from a patient with meningitis.

    PubMed

    Lalitha, M K; Anandi, V; Srivastava, A; Thomas, K; Cherian, A M; Chandi, S M

    1985-04-01

    A case of amoebic meningitis, presumably primary, was encountered in the Christian Medical College Hospital, Vellore, South India, in November 1983. The patient, a 40-year-old man, had cerebrospinal fluid rhinorrhea before the meningitis developed. Acanthamoeba culbertsoni was repeatedly demonstrated in and cultured from the cerebrospinal fluid. The patient responded dramatically to a combination therapy of penicillin and chloramphenicol. PMID:3988911

  5. Acanthamoeba polyphaga mimivirus Virophage Seroconversion in Travelers Returning from Laos

    PubMed Central

    Parola, Philippe; Renvoisé, Aurélie; Botelho-Nevers, Elisabeth; La Scola, Bernard; Desnues, Christelle

    2012-01-01

    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. PMID:22932431

  6. Ray vector fields, prismatic effect, and thick astigmatic optical systems.

    PubMed

    Harris, W F

    1996-06-01

    The application of the concept of ray vector fields to optical systems is reexamined. Paraxial or linear optics defines a four-dimensional ray vector field for any optical system: the vector field maps the incident ray vector into the emergent ray vector. In the case of thin systems, including thin astigmatic lenses, one can define a vector field of reduced dimensionality: the vector field is two-dimensional and maps the ray's incident position into the change in reduced direction. When the index of refraction is the same before and after a thin system, the change in reduced direction is the reduced deflection through the system or the reduced prismatic effect. Contrary to what has recently been claimed, this type of two-dimensional vector field does not apply in general to thick systems. However, a number of different types of two-dimensional vector fields can be defined for various particular classes of optical systems. Thick systems differ qualitatively from thin systems. They do not have equivalent thin lenses and cannot generally be replaced by thin lenses. Equations are derived for the change in reduced direction and deflection for a ray through optical systems in general and through separated two- and three-lens systems in particular. PMID:8807654

  7. Prevalence of Corneal Astigmatism in Tohono O'odham Native American Children 6 Months to 8 Years of Age

    PubMed Central

    Dobson, Velma; Miller, Joseph M.; Schwiegerling, Jim; Clifford-Donaldson, Candice E.; Green, Tina K.; Messer, Dawn H.

    2011-01-01

    Purpose. To describe the prevalence of corneal astigmatism in infants and young children who are members of a Native American tribe with a high prevalence of refractive astigmatism. Methods. The prevalence of corneal astigmatism was assessed by obtaining infant keratometer (IK4) measurements from 1235 Tohono O'odham children, aged 6 months to 8 years. Results. The prevalence of corneal astigmatism >2.00 D was lower in the 1- to <2-year-old age group when compared with all other age groups, except the 6- to <7-year-old group. The magnitude of mean corneal astigmatism was significantly lower in the 1- to <2-year age group than in the 5- to <6-, 6- to <7-, and 7- to <8-year age groups. Corneal astigmatism was with-the-rule (WTR) in 91.4% of astigmatic children (≥1.00 D). Conclusions. The prevalence and mean amount of corneal astigmatism were higher than reported in non–Native American populations. Mean astigmatism increased from 1.43 D in 1-year-olds to nearly 2.00 D by school age. PMID:21460261

  8. Identification of Unusual Phospholipid Fatty Acyl Compositions of Acanthamoeba castellanii

    PubMed Central

    Palusinska-Szysz, Marta; Kania, Magdalena; Turska-Szewczuk, Anna; Danikiewicz, Witold; Russa, Ryszard; Fuchs, Beate

    2014-01-01

    Acanthamoeba are opportunistic protozoan pathogens that may lead to sight-threatening keratitis and fatal granulomatous encephalitis. The successful prognosis requires early diagnosis and differentiation of pathogenic Acanthamoeba followed by aggressive treatment regimen. The plasma membrane of Acanthamoeba consists of 25% phospholipids (PL). The presence of C20 and, recently reported, 28- and 30-carbon fatty acyl residues is characteristic of amoeba PL. A detailed knowledge about this unusual PL composition could help to differentiate Acanthamoeba from other parasites, e.g. bacteria and develop more efficient treatment strategies. Therefore, the detailed PL composition of Acanthamoeba castellanii was investigated by 31P nuclear magnetic resonance spectroscopy, thin-layer chromatography, gas chromatography, high performance liquid chromatography and liquid chromatography-mass spectrometry. Normal and reversed phase liquid chromatography coupled with mass spectrometric detection was used for detailed characterization of the fatty acyl composition of each detected PL. The most abundant fatty acyl residues in each PL class were octadecanoyl (18∶0), octadecenoyl (18∶1 Δ9) and hexadecanoyl (16∶0). However, some selected PLs contained also very long fatty acyl chains: the presence of 28- and 30-carbon fatty acyl residues was confirmed in phosphatidylethanolamine (PE), phosphatidylserine, phosphatidic acid and cardiolipin. The majority of these fatty acyl residues were also identified in PE that resulted in the following composition: 28∶1/20∶2, 30∶2/18∶1, 28∶0/20∶2, 30∶2/20∶4 and 30∶3/20∶3. The PL of amoebae are significantly different in comparison to other cells: we describe here for the first time unusual, very long chain fatty acids with Δ5-unsaturation (30∶35,21,24) and 30∶221,24 localized exclusively in specific phospholipid classes of A. castellanii protozoa that could serve as specific biomarkers for the presence of these

  9. Changes in falling risk depending on induced axis directions of astigmatism on static posture

    PubMed Central

    Kim, Sang-Yeob; Moon, Byeong-Yeon; Cho, Hyun Gug

    2015-01-01

    [Purpose] To assess the changes in falling risk depending on the induced axis direction of astigmatism using cylindrical lenses in a static posture. [Subjects and Methods] Twenty subjects (10 males, 10 females; mean age, 23.4 ± 2.70 years) fully corrected by subjective refraction participated. To induce myopic simple astigmatism conditions, cylindrical lenses of +0.50, +1.00, +1.50, +2.00, +3.00, +4.00, and +5.00 D were used. The direction of astigmatic axes were induced under five conditions with increased cylindrical powers:, 180°, 90°, and 45° on both eyes; 180°/90° right/left eye, and 45°/135° right/left eye. Changes in the fall risk index were analyzed using the TETRAX biofeedback system. Measurements were performed for 32 seconds for each condition. [Results] The fall risk index increased significantly from C+4.00 D in 180°/90° right/left eye, C+3.00 D in 45°/135° right/left eye, and C+3.00 D in 45° on both eyes versus corrected emmetropia. Among the five axis conditions with the same cylindrical power lenses, the increase in the fall risk index was highest at 45° in both eyes. [Conclusion] Uncorrected oblique astigmatism may increase falling risk compared to with-the-rule and against-the-rule astigmatism. Clinical specialists should consider appropriate correction of astigmatism for preventing falls, especially for uncorrected oblique astigmatism. PMID:26180360

  10. The effect of corneal irregularity on astigmatism measurement by automated versus ray tracing keratometry.

    PubMed

    Roh, Hyun Cheol; Chuck, Roy S; Lee, Jimmy K; Park, Choul Yong

    2015-04-01

    The aim of this study was to compare the effect of corneal irregularity on astigmatism assessment using automated keratometry (AK) (IOLMaster) versus ray tracing keratometry (Pentacam). This is an observational case series approved by the institutional review board of Dongguk University Hospital, Goyang, South Korea. A total of 207 eyes of 207 cataract patients were included. Preoperative corneal astigmatism was measured by both IOLMaster and Pentacam. Corneal irregularity index (IR) was calculated in Fourier analysis map of Pentacam. AK by IOLMaster and total corneal refractive power (TCRP, 3 mm and 4 mm zone analysis with pupil centered) by Pentacam were selected and the difference between the 2 measurements (delta Δ) was calculated using vector analysis. Ocular residual astigmatism (ORA) after cataract surgery was calculated by subtracting 6-month postoperative refractive astigmatism (RA) measurements from corresponding preoperative values (AK, TCRP3, and TCRP4). The mean irregularity index measured was 0.042 ± 0.019 mm (mean ± standard deviation) and was positively correlated with age and magnitude of corneal astigmatism (P < 0.001 and P < 0.05). The difference (Δ) between TCRPs and AK (ΔTCRPs-AK) was 0.43 ± 0.37 (TCRP3) and 0.39 ± 0.35 (TCRP4) diopters. Linear regression analysis revealed that age (P < 0.001), IR (P < 0.001), and AK (P < 0.001) were positively correlated with ΔTCRPs-AK. In highly irregular corneas (IR over 0.77 diopters: mean + 2 standard deviation), postoperative ORAs calculated using TCRPs were significantly lower than ORAs calculated using AK. Corneal irregularities significantly impact astigmatism assessment by IOLMaster (AK) and Pentacam (TCRPs). Compared with AK, TCRPs were more accurate in predicting postoperative residual astigmatism in highly irregular corneas.

  11. A novel color-LED corneal topographer to assess astigmatism in pseudophakic eyes

    PubMed Central

    Ferreira, Tiago B; Ribeiro, Filomena J

    2016-01-01

    Purpose To assess the accuracy of corneal astigmatism evaluation measured by four techniques, Orbscan IIz®, Lenstar LS900®, Cassini®, and Total Cassini (anterior + posterior surface), in pseudophakic eyes. Patients and methods A total of 30 patients (46 eyes) who had undergone cataract surgery with the implantation of a monofocal intraocular lens (AcrySof IQ) were assessed after surgery. For each eye, subjective assessment of astigmatism and its axis was performed. Minimum, maximum, and mean keratometry and astigmatism and its axis were evaluated using the four measurement techniques. All measurements were compared with the subjective measurements. Agreement between each measurement technique and subjective assessment was evaluated using Bland–Altman plots. Linear regressions were performed and compared. Results Linear regression analysis of astigmatism axis showed very high R2 for all models, with Total Cassini showing the least difference to the unit slope (0.052) and the least difference to a null constant (3.790), although not statistically different from the other models. Regarding astigmatism value, the Cassini and Total Cassini models were similar and statistically better than the Lenstar model. Cassini and Total Cassini showed better J0 compared with Orbscan. Conclusion On linear regression models, Cassini and Total Cassini showed the best performance regarding astigmatism value. Cassini and Total Cassini also showed the least J0 deviation from the Cartesian origin compared with Orbscan, which had the lowest performance. Total corneal measurement with the color LED topographer seems to be a better technique for astigmatism assessment. PMID:27574391

  12. Toric intraocular lenses for correction of astigmatism in keratoconus and after corneal surgery

    PubMed Central

    Mol, Ilse EMA; Van Dooren, Bart TH

    2016-01-01

    Purpose To describe the results of cataract extraction with toric intraocular lens (IOL) implantation in patients with preexisting astigmatism from three corneal conditions (keratoconus, postkeratoplasty, and postpterygium surgery). Methods Cataract patients with topographically stable, fairly regular (although sometimes very high) corneal astigmatism underwent phacoemulsification with implantation of a toric IOL (Zeiss AT TORBI 709, Alcon Acrysof IQ toric SN6AT, AMO Tecnis ZCT). Postoperative astigmatism and refractive outcomes, as well as visual acuities, vector reduction, and complications were recorded for all eyes. Results This study evaluated 17 eyes of 16 patients with a mean age of 60 years at the time of surgery. Mean follow-up in this study was 12 months. The corrected distance Snellen visual acuity (with spectacles or contact lenses) 12 months postoperatively was 20/32 or better in 82% of eyes. The mean corneal astigmatism was 6.7 diopters (D) preoperatively, and 1.5 D of refractive cylinder at 1-year follow-up. No vision-compromising intra- or postoperative complications occurred and decentration or off-axis alignment of toric IOLs were not observed. Conclusion Phacoemulsification with toric IOL implantation was a safe and effective procedure in the three mentioned corneal conditions. Patient selection, counseling, and IOL placement with optimal astigmatism correction are crucial. PMID:27382249

  13. Convergence Insufficiency, Accommodative Insufficiency, Visual Symptoms, and Astigmatism in Tohono O'odham Students

    PubMed Central

    Twelker, J. Daniel; Miller, Joseph M.; Campus, Irene

    2016-01-01

    Purpose. To determine rate of convergence insufficiency (CI) and accommodative insufficiency (AI) and assess the relation between CI, AI, visual symptoms, and astigmatism in school-age children. Methods. 3rd–8th-grade students completed the Convergence Insufficiency Symptom Survey (CISS) and binocular vision testing with correction if prescribed. Students were categorized by astigmatism magnitude (no/low: <1.00 D, moderate: 1.00 D to <3.00 D, and high: ≥3.00 D), presence/absence of clinical signs of CI and AI, and presence of symptoms. Analyses determine rate of clinical CI and AI and symptomatic CI and AI and assessed the relation between CI, AI, visual symptoms, and astigmatism. Results. In the sample of 484 students (11.67 ± 1.81 years of age), rate of symptomatic CI was 6.2% and symptomatic AI 18.2%. AI was more common in students with CI than without CI. Students with AI only (p = 0.02) and with CI and AI (p = 0.001) had higher symptom scores than students with neither CI nor AI. Moderate and high astigmats were not at increased risk for CI or AI. Conclusions. With-the-rule astigmats are not at increased risk for CI or AI. High comorbidity rates of CI and AI and higher symptoms scores with AI suggest that research is needed to determine symptomatology specific to CI. PMID:27525112

  14. Accuracy of the Welch Allyn Suresight for measurement of magnitude of astigmatism in 3- to 7-year-old children

    PubMed Central

    Harvey, Erin M.; Dobson, Velma; Miller, Joseph M.; Clifford-Donaldson, Candice E.; Green, Tina K.; Messer, Dawn H.; Garvey, Katherine A.

    2009-01-01

    Purpose To evaluate the accuracy of the Welch Allyn SureSight in noncycloplegic measurements of astigmatism as compared to cycloplegic Retinomax K+ autorefractor measurements of astigmatism in children from a Native American population with a high prevalence of high astigmatism. Methods Data are reported for 825 3- to 7-year-old children with no ocular abnormalities. Each child had a Retinomax K+ cycloplegic measurement of right eye astigmatism with a confidence rating ≥8 and 3 attempts to obtain a SureSight measurement on the right eye. Results SureSight measurement success rates did not differ significantly across age or measurement confidence rating (<6 vs ≥6). Ninety-six percent of children had at least 1 measurement (any confidence), and 89% had at least 1 measurement with confidence at the manufacturer's recommended value (≥6). Overall, the SureSight tended to overestimate astigmatism. If the SureSight measurement had any dioptric value (0.00 D to 3.00 D), astigmatism of 2.00 D or less was likely to be present. If the SureSight showed astigmatism beyond the instrument's dioptric range (>3.00 D), Retinomax K+ measurements indicated that >2.00 D of astigmatism was present in 136 of 157 (86.6%). In cooperative children for whom the SureSight would not give a reading, 32 of 34 (94%) had >3.00 D of astigmatism. Conclusions The SureSight does not provide an accurate, quantitative measure of amount of astigmatism. However, it does allow accurate categorization of amount of astigmatism as ≤2.00 D, >2.00 D, or >3.00 D, and it has high measurement success rate in young children. PMID:19840726

  15. Distribution and Repeatability of Corneal Astigmatism Measurements (Magnitude and Axis) Evaluated With Color Light Emitting Diode Reflection Topography

    PubMed Central

    Asimellis, George

    2015-01-01

    Purpose: To evaluate and investigate the distribution and repeatability of anterior corneal surface astigmatism measurements (axis and magnitude) using a novel corneal topographer. Methods: Anterior corneal surface astigmatism was investigated in a total of 195 eyes using a novel multicolored spot reflection topographer (Cassini; i-Optics). Two patient groups were studied, a younger-age group A and an older-age group B. Three consecutive acquisitions were obtained from each eye. The repeatability of measurement was assessed using Bland–Altman plot analysis and is reported as the coefficient of repeatability. Results: Group A (average age 34.3 years) had on average with-the-rule astigmatism, whereas the older-age group B (average age 72.3 years) had on average against-the-rule astigmatism. Average astigmatism magnitude measurement repeatability in group A was 0.4 diopters (D) and in group B 0.4 D. Average astigmatism axis measurement repeatability in group A was 5.4 degrees and in group B 5.5 degrees. The axis measurement repeatability improved with increasing magnitude of astigmatism: in the subgroups with astigmatism between 3.0 and 6.0 D, the axis repeatability was 1.4 degrees (group A) and 1.2 degrees (group B), whereas in the subgroups with astigmatism larger than 6.0 D, the repeatability was 1.1 and 0.6 degrees, respectively. Conclusions: This novel corneal topography device seems to offer high precision in reporting corneal astigmatism. This study reaffirms the established trend of a corneal astigmatism shift from an average “with-the-rule” to “against-the-rule” with aging. PMID:26057324

  16. Thermotolerant Acanthamoeba spp. isolated from therapeutic hot springs in Northwestern Iran.

    PubMed

    Solgi, Rahmat; Niyyati, Maryam; Haghighi, Ali; Taghipour, Niloofar; Tabaei, Seyyed Javad Seyyed; Eftekhar, Mohamad; Nazemalhosseini Mojarad, Ehsan

    2012-12-01

    This study was conducted to address the distribution of Acanthamoeba genotypes in therapeutic hot springs in Iran. Sixty water and sediment samples were collected from bicarbonate, sulphur, and sodium chloride thermal springs in the northwest. All hot springs examined are used mainly for health purposes in Iran. Acanthamoeba were identified by both morphology and PCR (polymerase chain reaction). Genotype identification was based on the sequencing of a highly variable and informative region of Diagnostic Fragment 3 (stem 29-1 of 18S rRNA gene) within Acanthamoeba-specific amplimer (ASA.S1). Twenty percent of hot springs were contaminated with thermotolerant Acanthamoeba belonging to the potentially pathogenic T4 and T3 genotypes. A high number (91.7%) of strains showed growth at 37 °C, and eight isolates showed growth at 42 °C. A single isolate (HSNW2) was detected in waters at 70 °C. The presence of thermotolerant Acanthamoeba highlights a risk factor for susceptible individuals, as Acanthamoeba-related keratitis continues to rise in Iran. Periodic surveillance of thermal waters as well as improved filtration and disinfection is recommended to prevent disease related to pathogenic Acanthamoeba. This is the first comprehensive molecular study of Acanthamoeba genotypes in hot springs in Iran and the first to report the occurrence of the T3 genotype (corresponding to Acanthamoeba griffini) in thermal water sources in this country.

  17. Seasonal distribution of potentially pathogenic Acanthamoeba species from drinking water reservoirs in Taiwan.

    PubMed

    Kao, Po-Min; Hsu, Bing-Mu; Hsu, Tsui-Kang; Liu, Jorn-Hon; Chang, Hsiang-Yu; Ji, Wen-Tsai; Tzeng, Kai-Jiun; Huang, Shih-Wei; Huang, Yu-Li

    2015-03-01

    In order to detect the presence/absence of Acanthamoeba along with geographical variations, water quality variations and seasonal change of Acanthamoeba in Taiwan was investigated by 18S ribosomal RNA (rRNA) gene TaqMan quantitative real-time PCR. Samples were collected quarterly at 19 drinking water reservoir sites from November 2012 to August 2013. Acanthamoeba was detected in 39.5 % (30/76) of the water sample, and the detection rate was 63.2 % (12/19) from samples collected in autumn. The average concentration of Acanthamoeba was 3.59 × 10(4) copies/L. For geographic distribution, the detection rate for Acanthamoeba at the northern region was higher than the central and southern regions in all seasons. Results of Spearman rank test revealed that heterotrophic plate count (HPC) had a negative correlation (R = -0.502), while dissolved oxygen (DO) had a positive correlation (R = 0.463) in summer. Significant differences were found only between the presence/absence of Acanthamoeba and HPC in summer (Mann-Whitney U test, P < 0.05). T2 and T4 genotypes of Acanthamoeba were identified, and T4 was the most commonly identified Acanthamoeba genotypes. The presence of Acanthamoeba in reservoirs presented a potential public health threat and should be further examined.

  18. Morpho-Physiological and Biochemical Criteria of Acanthamoeba spp. Isolated from the Egyptian Aquatic Environment

    PubMed Central

    Al-Herrawy, A; Bahgat, M; Mohammed, A; Ashour, A; Hikal, W

    2013-01-01

    Background The free-living amoebae Acanthamoeba spp., have been recognized as etiologic agents of amoebic encephalitis, keratitis, otitis, lung lesions and other skin infections mainly in immuno-compromised individuals. In this study, morpho-physiological and biochemical characterization of Acanthamoeba strains isolated from the Egyptian aquatic environment were surveyed. Methods Some Acanthamoeba species were cultivated on non-nutrient agar. Isolated strains of Acanthamoeba were identification based on the morphology of trophic and cyst forms in addition to temperature and osmo-tolerance assays. Biochemical characterization of the isolated amoeba strains was performed using quantitative assay as well as qualitative determination of proteolytic activity in zymograph analysis. Results Potentially pathogenic Acanthamoeba species were isolated from all of the examined water sources. Colorimetric assays showed protease activity in the heat-tolerant isolates of Acanthamoeba. All pathogenic isolates of Acanthamoeba exhibited higher protease activity than did the non-pathogenic ones. The zymographic protease assays showed various banding patterns for different strains of Acanthamoeba. Conclusion The incidence and prevalence of the pathogenic Acanthamoeba species in the aquatic environment using parasitological and biochemical diagnostic tools will provide baseline data against which the risk factors associated with waterborne transmission can be identified. PMID:23914245

  19. Detection of glycoproteins in the Acanthamoeba plasma membrane

    SciTech Connect

    Paatero, G.I.L. ); Gahmberg, C.G. )

    1988-11-01

    In the present study the authors have shown that glycoproteins are present in the plasma membrane of Acanthamoeba castellanii by utilizing different radioactive labeling techniques. Plasma membrane proteins in the amoeba were iodinated by {sup 125}I-lactoperoxidase labeling and the solubilized radiolabeled glycoproteins were separated by lectin-Sepharose affinity chromatography followed by polyacrylamide gel electrophoresis. The periodate/NaB{sup 3}H{sub 4} and galactose oxidase/NaB{sup 3}H{sub 4} labeling techniques were used for labeling of surface carbohydrates in the amoeba. Several surface-labeled glycoproteins were observed in addition to a diffusely labeled region with M{sub r} of 55,000-75,000 seen on electrophoresis, which could represent glycolipids. The presence of glycoproteins in the plasma membrane of Acanthamoeba castellanii was confirmed by metabolic labeling with ({sup 35}S)methionine followed by lectin-Sepharose affinity chromatography and polyacrylamide gel electrophoresis.

  20. [A case of meningoencephalitis caused by Acanthamoeba sp. in Dakar].

    PubMed

    Ndiaye, M; Diop, A G; Dieng, Y; Seydi, M; Diouf, F S; Diop, B M; Ndiaye, I P

    2005-01-01

    Primary meningoencephalitis caused by free-living soil ameba is rare. We report the first diagnosed case of meningoencephalitis due to Acanthamoeba sp. in Senegal. The patient was a 24-year-old Senegalese woman hospitalized in the neurology department of Fann Hospital. Diagnosis was made 6 months after the onset of symptoms based mainly on headache with fever usually occurring in the evening, chills, and lumbar puncture demonstrating turbid fluid. Parasitological examination of cool cerebrospinal fluid sediment revealed the presence of free-living ameba trophozoites of the Acanthamoeba genus. Species determination by culture on 1.5% agar-agar enriched with Escherichia coli failed. The patient died one month following initiation of treatment using amphotericine B. PMID:15903081

  1. [First experience of intrastromal ring segments insertion for correction of posttraumatic cicatricial corneal astigmatism].

    PubMed

    Neroev, V V; Gundorova, R A; Beliaev, D S; Petukhova, A B; Oganesian, O G; Penkina, A V

    2013-01-01

    The potential of MAGELLAN MAPPER corneal topographer in evaluation of corneal refraction in the early postoperative period after surgical debrigement of scleral and corneal penetrating wounds is shown. The accuracy of corneal topography is satisfactory and its results reproducible what makes the method suitable for evaluation of corneal refraction and follow-up in patients with penetrating wounds and scarring of sclera and cornea. The possibility of posttraumatic cicatricial astigmatism correction by insertion of Keraring intrastromal corneal ring segments (ICRS) using femtosecond surgical laser FEMTO LDV were studied. Results of cicatricial corneal astigmatism correction in early posttraumatic period are encouraging.

  2. Broadband astigmatism-corrected spectrometer design using a toroidal lens and a special filter

    NASA Astrophysics Data System (ADS)

    Ge, Xianying; Chen, Siying; Zhang, Yinchao; Chen, He; Guo, Pan; Mu, Taotao; Yang, Jian; Bu, Zhichao

    2015-01-01

    In the paper, a method to obtain a broadband, astigmatism-corrected spectrometer based on the existing Czerny-Turner spectrometer is proposed. The theories of astigmatism correction using a toroidal lens and a special filter are described in detail. Performance comparisons of the modified spectrometer and the traditional spectrometer are also presented. Results show that with the new design the RMS spot radius in sagittal view is one-eightieth of that in the traditional spectrometer over a broadband spectral range from 300 to 700 nm, without changing or moving any optical elements in the traditional spectrometer.

  3. Low-cost adaptive astigmatism compensator for improvement of eye fundus camera.

    PubMed

    Arines, Justo; Acosta, Eva

    2011-11-01

    In this work we show a conceptually simple and cheap means by which to improve retinal image quality in fundus cameras. We will explain how to build a low-cost variable astigmatism-correcting device with a pair of identical commercial ophthalmic lenses. We have developed and tested a low order aberration compensation device capable of correcting astigmatism prescriptions up to -8.00 D with no significant addition of higher order aberrations. A theoretical description of the device, calibration, and improvement in retinal images without employing any image restoration technique will be shown. PMID:22048352

  4. Toric intraocular lens orientation and residual refractive astigmatism: an analysis

    PubMed Central

    Potvin, Rick; Kramer, Brent A; Hardten, David R; Berdahl, John P

    2016-01-01

    Purpose To analyze intraocular lens (IOL) orientation data from an online toric back-calculator (astigmatismfix.com) for determining if differences were apparent by lens type. Methods A retrospective review of astigmatismfix.com toric back-calculations that included IOL identification and intended orientation axis. Results Of 12,812 total validated calculation records, 8,229 included intended orientation and lens identification data. Of the latter, 5,674 calculations (69%) involved lenses oriented 5° or more from their intended position. Using estimated toric lens usage data, the percentage of lenses with orientation ≥5° from intended was 0.89% overall, but the percentage varied significantly between specific toric lens brands (P<0.05). The percentage of back-calculations related to lenses that were not oriented as intended was also statistically significantly different by lens brand (P<0.05). When IOLs were misoriented, they were significantly more likely to be misoriented in a counterclockwise direction (P<0.05). This was found to be due to a bias toward counterclockwise orientation observed with one specific brand, a bias that was not observed with the other three brands analyzed here. Conclusion The percentage of eyes with lens orientation ≥5° from intended in the Toric Results Analyzer data set was <1% of toric IOLs in general, with the relative percentage of Tecnis® Toric IOLs significantly higher than AcrySof® Toric IOLs. Both of these had higher rates than the Staar® Toric and Trulign® Toric lenses, with the availability of higher Tecnis and AcrySof cylinder powers a likely contributing factor. The AcrySof Toric IOL appears to be less likely than the Tecnis Toric IOL to cause residual astigmatism as a result of misorientation. The Tecnis Toric IOL appears more likely to be misoriented in a counterclockwise direction; no such bias was observed with the AcrySof Toric, the Trulign® Toric, or the Staar Toric IOLs. PMID:27703323

  5. In vitro fusion of Acanthamoeba phagolysosomes. I. Demonstration and quantitation of vacuole fusion in Acanthamoeba homogenates.

    PubMed

    Oates, P J; Touster, O

    1976-02-01

    Fusion of phagolysosomes (PLs) has been demonstrated to occur in vitro. Two separate cell homogenates of the ameba Acanthamoeba sp. (Neff) were prepared, each rich in PLs labeled with distinctive particulate markers. Portions of each were incubated together in vitro and fusion occurred as evidenced by the appearance of PLs containing both types of markers. Fusion was confirmed by electron microscopy, including serial sectioning. The membranes of fused vacuoles excluded the dye eosin Y. Surviving cells in the homogenates were not responsible for the observed fusion. Fusion was obtained using either synthetic markers (polystyrene and polyvinyltoluene latex) or biological markers (autoclaved yeast cells and glutaraldehyde-fixed goat red blood cells), or a combination of both. The specificity of PL fusion in vivo appeared to be maintained in vitro. As determined by light and electron microscopy, the fusion reaction was dependent on time and temperature, and on the initial presence of membrane around both marker particles. A minimum of 10% of the vacuoles fused by 10 min of incubation at 30 degrees C, and no rupture of the vacuoles was detected during this time. After 10 min of incubation, vacuole rupture began and fusion ceased. At a constant initial vacuole concentration, the extent of PL fusion in vitro was quantitatively reproducible. This appears to be a promising system for further investigation of membrane fusion in the lysosomal system. PMID:1245550

  6. Anti-Acanthamoeba activity of contact lens solutions

    PubMed Central

    Niszl, I.; Markus, M.

    1998-01-01

    AIMS—This study was undertaken to investigate the effects of contact lens disinfecting solutions on strains of Acanthamoeba from the United Kingdom and southern Africa and to compare the results with those of other researchers. No information was previously available for southern African isolates.
METHODS—11 contact lens solutions were tested on cysts of 10 strains of Acanthamoeba.
RESULTS—Not all solutions used in the study were effective, with some for hard and gas permeable contact lenses being more satisfactory than those for soft contact lenses. The most effective of the gas permeable and hard contact lens solutions tested was Transoak (0.01% (wt/vol) benzalkonium chloride), which killed cysts of all strains within 4 hours of exposure. Oxysept 1 (31 mg hydrogen peroxide/ml) was the best soft contact lens solution tested. It eliminated cysts of certain strains within 4 hours, whereas cysts of other strains were only inactivated within either 8 or 72 hours.
CONCLUSIONS—Manufacturers should be aware of the killing time for Acanthamoeba by contact lens solutions and should provide appropriate guidelines for the use thereof. The killing time for cysts of the African and UK isolates studied is, in general, similar. Therefore, it must in the present state of knowledge be assumed that usage guidelines suggested in the UK are also appropriate for travellers to South Africa and for local residents in South Africa.

 Keywords: contact lenses; Acanthamoeba; keratitis PMID:9893594

  7. Field's stain--a rapid staining method for Acanthamoeba spp.

    PubMed

    Pirehma, M; Suresh, K; Sivanandam, S; Anuar, A K; Ramakrishnan, K; Kumar, G S

    1999-10-01

    Acanthamoeba sp. is a free-living amoeba known to cause chronic central nervous system infection or eye infection in humans. Many cases remain undetected for want of a good detection system. We report for the first time a rapid staining method to facilitate the identification of Acanthamoeba sp. using the modified Field's staining technique. A. castellanii, which was used in the present experiment, is maintained in our laboratory in mycological peptone medium (Gibco). The cultures were pooled together and smears were made on glass slides for staining purposes. Different types of stains such as Field's stain, modified Field's stain, Wright's stain, Giemsa stain, Ziehl-Neelsen stain, and trichrome stain were used to determine the best stain for the identification of this amoeba. The concentration of various stains and the duration of staining were varied to provide the best color and contrast for each stain. Acanthamoeba was also obtained from the brain of experimentally infected mice and was stained with various stains as mentioned above to determine the best stain for use in identifying the presence of this parasite in experimentally infected animals. The modified Field's stain gives a very good color contrast as compared with other stains. Furthermore, it takes only 20 s to be carried out using the least number of reagents, making it suitable for both laboratory and field use.

  8. An Acanthamoeba sp. containing two phylogenetically different bacterial endosymbionts

    PubMed Central

    Heinz, Eva; Kolarov, Irina; Kästner, Christian; Toenshoff, Elena R; Wagner, Michael; Horn, Matthias

    2007-01-01

    Acanthamoebae are ubiquitous free-living amoebae and important predators of microbial communities. They frequently contain obligate intracellular bacterial symbionts, which show a worldwide distribution. All Acanthamoeba spp. described so far harboured no or only a single specific endosymbiont phylotype, and in some cases evidence for coevolution between the symbiotic bacteria and the amoeba host has been reported. In this study we have isolated and characterized an Acanthamoeba sp. (strain OEW1) showing a stable symbiotic relationship with two morphologically different endosymbionts. 16S rRNA sequence analysis assigned these symbionts to the candidate genus Procabacter (Betaproteobacteria) and the genus Parachlamydia (Chlamydiae) respectively. Fluorescence in situ hybridization and transmission electron microscopy confirmed the affiliation of the endosymbionts and showed their co-occurrence in the amoeba host cells and their intracellular location within separate compartments enclosed by host-derived membranes. Further analysis of this stable relationship should provide novel insights into the complex interactions of intracellular multiple-partner associations. PMID:17504498

  9. Efficiency of water disinfectants against Legionella pneumophila and Acanthamoeba.

    PubMed

    Dupuy, Mathieu; Mazoua, Stéphane; Berne, Florence; Bodet, Charles; Garrec, Nathalie; Herbelin, Pascaline; Ménard-Szczebara, Florence; Oberti, Sandrine; Rodier, Marie-Hélène; Soreau, Sylvie; Wallet, France; Héchard, Yann

    2011-01-01

    Free-living amoebae might be pathogenic by themselves and be a reservoir for bacterial pathogens, such as Legionella pneumophila. Not only could amoebae protect intra-cellular Legionella but Legionella grown within amoebae could undergo physiological modifications and become more resistant and more virulent. Therefore, it is important to study the efficiency of treatments on amoebae and Legionella grown within these amoebae to improve their application and to limit their impact on the environment. With this aim, we compared various water disinfectants against trophozoites of three Acanthamoeba strains and L. pneumophila alone or in co-culture. Three oxidizing disinfectants (chlorine, monochloramine, and chlorine dioxide) were assessed. All the samples were treated with disinfectants for 1 h and the disinfectant concentration was followed to calculate disinfectant exposure (Ct). We noticed that there were significant differences of susceptibility among the Acanthamoeba strains. However no difference was observed between infected and non-infected amoebae. Also, the comparison between the three disinfectants indicates that monochloramine was efficient at the same level towards free or co-cultured L. pneumophila while chlorine and chlorine dioxide were less efficient on co-cultured L. pneumophila. It suggests that these disinfectants should have different modes of action. Finally, our results provide for the first time disinfectant exposure values for Acanthamoeba treatments that might be used as references for disinfection of water systems.

  10. Use of multiple immunosuppressive agents in recalcitrant ACANTHAMOEBA scleritis.

    PubMed

    Igras, Estera; Murphy, Conor

    2015-01-01

    A 48-year-old woman who is a contact lens wearer presented with unilateral ACANTHAMOEBA keratitis, confirmed by PCR, which responded initially to topical polyhexamethylene biguanide (PHMB) and brolene. Three months later, despite continued treatment, she developed diffuse anterior scleritis with severe pain and marked scleral injection but without evidence of recurrence keratitis. Oral non-steroidal anti-inflammatories and oral high-dose corticosteroids were added without success. Subsequent treatment with intravenous methylprednisolone and high-dose cyclosporine led to a temporary improvement. Re-presenting with signs of recurrent scleritis and severe pain, the antitumor necrosis factor monoclonal antibody adalimumab, and later oral cyclophosphamide, were added. This led to complete quiescence of the scleritis. Unfortunately, frequent recurrences of ACANTHAMOEBA keratitis and anterior uveitis occurred on immunosuppression requiring continued treatment with PHMB, brolene and topical corticosteroids. This is the first case of severe refractory ACANTHAMOEBA scleritis requiring the concomitant use of four immunosuppressive agents to achieve continued disease control. The challenges in managing this case are discussed.

  11. Genotypic characterization of amoeba isolated from Acanthamoeba keratitis in Poland.

    PubMed

    Derda, Monika; Solarczyk, Piotr; Cholewiński, Marcin; Hadaś, Edward

    2015-03-01

    Free-living amoebae belonging to the genus Acanthamoeba are the causative factor of many diseases. Among others, they cause Acanthamoeba keratitis (AK), a condition that usually occurs in contact lens wearers, though it is also observed in non-wearers. The number of diagnosed cases of AK increased more than eightfold during 8 years in the USA, and a proportional increase in frequency also occurred in Poland and Europe. Cases of AK are usually diagnosed late, and their therapy is difficult and rarely successful. AK is an uncommon diagnosis in Poland. The increased number of positive cases observed in our laboratory may reflect the growing at-risk population of contact lens wearers. Acanthamoeba as a genus of facultative human parasites is currently classified into 17 genotypes. Isolates belonging to seven genotypes were found to be associated with AK. One genotype in particular, T4, was found to be overrepresented in human disease. The main finding of our study is that in Poland, AK is almost always associated with the T4 genotype.

  12. Partial characterization of Acanthamoeba castellanii (T4 genotype) DNase activity.

    PubMed

    Iqbal, Junaid; Panjwani, Shamvil; Siddiqui, Ruqaiyyah; Khan, Naveed Ahmed

    2015-02-01

    The deoxyribonuclease (DNase) activities of Acanthamoeba castellanii belonging to the T4 genotype were investigated. Using zymographic assays, the DNase activities had approximate molecular masses of 25 and 35 kDa. A. castellanii DNases exhibited activity at wide-ranging temperature of up to 60 °C and at pH ranging from 4 to 9. The DNases activities were unaffected by proteinase-K treatment, divalent cations such as Ca(++), Cu(++), Mg(++), and Zn(++), or divalent cation chelating agent ethylenediaminetetraacetic acid (EDTA) or sodium dodecyl sulfate (SDS). The non-reliance on divalent cations and homology data suggests that A. castellanii DNases belong to the class of eukaryotic lysosomal DNase II but exhibit robust properties. The DNases activity in A. castellanii interfered with the genomic DNA extraction. Extraction methods involving EDTA, SDS, and proteinase-K resulted in low yield of genomic DNA. On the other hand, these methods resulted in high yield of genomic DNA from human cells suggesting the robust nature of A. castellanii DNases that are unaffected by reagents normally used in blocking eukaryotic DNases. In contrast, the use of chaotropic agent such as guanidine thiocyanate improved the yield of genomic DNA from A. castellanii cells significantly. Further purification and characterization of Acanthamoeba DNases is needed to study their non-classic distinct properties and to determine their role in the biology, cellular differentiation, cell cycle progression, and arrest of Acanthamoeba.

  13. Development of an immunochromatographic assay kit using fluorescent silica nanoparticles for rapid diagnosis of Acanthamoeba keratitis.

    PubMed

    Toriyama, Koji; Suzuki, Takashi; Inoue, Tomoyuki; Eguchi, Hiroshi; Hoshi, Saichi; Inoue, Yoshitsugu; Aizawa, Hideki; Miyoshi, Kazutomi; Ohkubo, Michio; Hiwatashi, Eiji; Tachibana, Hiroshi; Ohashi, Yuichi

    2015-01-01

    We developed an immunochromatographic assay kit that uses fluorescent silica nanoparticles bound to anti-Acanthamoeba antibodies (fluorescent immunochromatographic assay [FICGA]) and evaluated its efficacy for the detection of Acanthamoeba and diagnosis of Acanthamoeba keratitis (AK). The sensitivity of the FICGA kit was evaluated using samples of Acanthamoeba trophozoites and cysts diluted to various concentrations. A conventional immunochromatographic assay kit with latex labels (LICGA) was also evaluated to determine its sensitivity in detecting Acanthamoeba trophozoites. To check for cross-reactivity, the FICGA was performed by using samples of other common causative pathogens of infectious keratitis, such as Pseudomonas aeruginosa, Staphylococcus aureus, Staphylococcus epidermidis, and Candida albicans. Corneal scrapings from patients with suspected AK were tested with the FICGA kit to detect the presence of Acanthamoeba, and the results were compared with those of real-time PCR. The FICGA kit detected organisms at concentrations as low as 5 trophozoites or 40 cysts per sample. There were no cross-reactivities with other pathogens. The FICGA was approximately 20 times more sensitive than the LICGA for the detection of Acanthamoeba trophozoites. The FICGA kit yielded positive results for all 10 patients, which corresponded well with the real-time PCR results. The FICGA kit demonstrated high sensitivity for the detection of Acanthamoeba and may be useful for the diagnosis of AK.

  14. Balamuthia mandrillaris and Acanthamoeba Amebic Encephalitis with Neurotoxoplasmosis Coinfection in a Patient with Advanced HIV Infection

    PubMed Central

    Chan, Joseph C.; Castellano-Sanchez, Amilcar; Hirzel, Alicia; Laowansiri, Panthipa; Tuda, Claudio; Visvesvara, Govinda S.; Qvarnstrom, Yvonne; Ratzan, Kenneth R.

    2012-01-01

    We describe a patient with advanced HIV infection and Balamuthia mandrillaris and Acanthamoeba amebic encephalitis with Toxoplasma gondii coinfection. A multidisciplinary effort and state-of-the-art diagnostic techniques were required for diagnosis. Our patient is the first reported case of an HIV-infected person with dual Balamuthia mandrillaris and Acanthamoeba amebic encephalitis with neurotoxoplasmosis coinfection. PMID:22170911

  15. Insights from the DNA databases: approaches to the phylogenetic structure of Acanthamoeba.

    PubMed

    Fuerst, Paul A

    2014-11-01

    Species of Acanthamoeba have been traditionally described using morphology (primarily cyst structure), or cytology of nuclear division (used by Pussard and Pons, 1977). Twenty-plus putative species were proposed based on such criteria. Morphology, however, is often plastic, dependent upon culture conditions. DNA sequences of the nuclear small subunit (18S) rRNA that can be used for the study of the phylogeny of Acanthamoeba have increased from a single sequence in 1986 to more than 1800 in 2013. Some of the patterns of the sequence data for Acanthamoeba are reviewed, and some of the insights that this data illuminates are illustrated. In particular, the data suggest the existence of 20 or more genotypic types, a number not dissimilar to the number of named species of Acanthamoeba. However, molecular studies make clear that the relationship between phylogenetic relatedness and species names as we know them for Acanthamoeba is tenuous at best.

  16. Isolation and Molecular Characterization of Acanthamoeba Strains from Dental Units in Costa Rica.

    PubMed

    Retana-Moreira, Lissette; Abrahams-Sandí, Elizabeth; Castro-Artavia, Esteban; Fernández-Sánchez, Ana; Castro-Castillo, Alfredo; Reyes-Batlle, María; Lorenzo-Morales, Jacob

    2015-01-01

    Free-living amoebae are protozoa widely distributed in nature, which can be found in a variety of environments. Four genera are recognized as causal agents of infections in humans and animals: Acanthamoeba, Naegleria, Balamuthia, and Sappinia. In this study, the presence of Acanthamoeba in dental units was determined and the isolates obtained were molecularly characterized; osmotolerance and thermotolerance assays were also performed to evaluate multiplication under these conditions, frequently associated with pathogenicity. The morphological analysis and partial sequencing of the 18S rDNA gene revealed the presence of Acanthamoeba genotype T4 in 14% of the units sampled. Osmotolerance and thermotolerance tests were positive for more than 80% of the isolates. Up to date, this is the first study that reports the detection, identification, and genotyping of Acanthamoeba isolated from dental units in Costa Rica and even in Latin-America. Further assays to determine the potential pathogenicity of these Acanthamoeba isolates are underway.

  17. Optical-vortex pair creation and annihilation and helical astigmatism of a nonplanar ring resonator

    SciTech Connect

    Heckenberg, N.R.; Vaupel, M.; Malos, J.T.; Weiss, C.O.

    1996-09-01

    The creation and annihilation of pairs of optical vortices have been studied in transitions between patterns produced in a photorefractive oscillator. Smooth metamorphosis between stable patterns occurs through pair creation or annihilation but can be modeled using superposition of modes taking into account lifting of degeneracy of helical modes by helical astigmatism of the resonator. {copyright} {ital 1996 The American Physical Society.}

  18. On the relation between power and astigmatism near an umbilic line.

    PubMed

    Rubinstein, Jacob

    2011-05-01

    The relation between the variation of power and astigmatism in a progressive power optical element is considered. The classical Minkwitz identity is revisited. Then, it is shown how to extend this identity, which applies to the geometry of surfaces, to optical parameters that are determined by the geometry of reflected or refracted wavefronts. PMID:21532682

  19. [Laser correction of myopia and myopic astigmatism in children--literature review].

    PubMed

    Mrukwa-Kominek, Ewa; Gierek-Ciaciura, Stanisława

    2003-01-01

    Anisometropic myopia and myopic astigmatism are very often refractive error in children. Suitable correction of different vision defects in children might prevent the consequences of amblyopia and lack of development of binocular vision. This article presents the effectiveness of correction in myopia and myopic anisometropia using laser method such as PRK, LASEK and LASIK. It is the literature review. PMID:15049271

  20. Evaluation of the toric implantable collamer lens for simultaneous treatment of myopia and astigmatism.

    PubMed

    Price, Marianne O; Price, Francis W

    2015-01-01

    Myopic astigmatism is a prevalent condition that can be treated with spectacles, contact lenses, or laser refractive surgery. However, these treatment options have functional limitations at higher levels of refractive error. The toric implantable collamer lens is designed to treat a broad range of refractive error, generally up to -18 diopters with +1 to +6 diopters of astigmatism. Approval for a more limited treatment range of up to 15 diopters of myopia with +1 to +4 diopters of astigmatism is being sought in the US, where this device has not yet received marketing approval. Surgical correction of high-myopic astigmatism can be life-altering and allow people to participate in activities that were not previously feasible because of visual limitations. The toric implantable collamer lens is implanted behind the iris and in front of the natural crystalline lens. With earlier lens designs, it was necessary to create an iridectomy or iridotomy to prevent pupillary block. The newest toric implantable collamer lens model has a small central hole that is not visually noticeable. This eliminates the need to create a hole in the iris, thereby enhancing the safety of the procedure.

  1. Biochemical characterization and functional studies of Acanthamoeba mannose-binding protein.

    PubMed

    Garate, Marco; Cubillos, Ibis; Marchant, Jeffrey; Panjwani, Noorjahan

    2005-09-01

    Acanthamoebae produce a painful, sight-threatening corneal infection. The adhesion of parasites to the host cells is a critical first step in the pathogenesis of infection. Subsequent to adhesion, the parasites produce a potent cytopathic effect (CPE) leading to target cell death. Recent studies showing that acanthamoebae express a mannose-binding protein (MBP) and that free alpha-mannose (alpha-Man) specifically inhibits the adhesion of parasites to host cells suggest that the MBP plays a key role in the pathogenesis of Acanthamoeba infection by mediating host-parasite interactions. However, direct evidence showing that Acanthamoeba MBP is a virulence protein has been lacking. In this study, we demonstrate that the polyclonal immunoglobulin Y (IgY) antibodies prepared against affinity-purified Acanthamoeba MBP markedly inhibit the adhesion of parasites to host cells. The antibody also inhibited the Acanthamoeba-induced CPE on host cells. In contrast, preimmune IgY did not influence either the adhesion of the parasites to host cells or the amoeba-induced CPE. Using a variety of approaches, including affinity chromatography on an alpha-Man gel, electrophoresis under native and denaturing conditions, biotinylation of cell surface proteins, and immunostaining, it was conclusively established that Acanthamoeba MBP is located on the surface membranes of the parasites. Neutral-sugar analysis and lectin binding experiments using succinylated concanavalin A, a plant lectin with high affinity for mannose, revealed that Acanthamoeba MBP is itself a mannose-containing glycoprotein. N-Glycanase treatment to remove N-linked oligosaccharides shifted the subunit molecular mass of MBP from 130 kDa to 110 kDa. Hexosamine analysis revealed that Acanthamoeba MBP lacks detectable levels of GalNAc, suggesting the absence of O-linked oligosaccharides. In summary, we have characterized Acanthamoeba MBP and have shown that it is a major virulence protein responsible for host

  2. [Results of corneal and total astigmatism estimation by different methods in myopic patients wearing orthokeratology contact lenses].

    PubMed

    Tarutta, E P; Aliaeva, O O; Verzhanskaia, T Iu; Milash, S V

    2013-01-01

    Reports have been made that corneal aberrations of all orders, including astigmatism, often significantly increase with the use of night orthokeratology lenses. In this study the dynamic changes of total and corneal astigmatism in myopes using orthokeratology lenses was evaluated by different methods. The study enrolled 38 patients (76 eyes) with low and medium myopia (28 and 48 eyes correspondingly) and initial astigmatism less than 2 diopters. The assessment was made before and in different terms after the patient started to wear orthokeratology lenses. Induced astigmatism (> or =1 diopter) was found in more than 50% of cases. The degree of astigmatism gradually increased from the centre to the periphery within the papillary zone. The maximum values were found within a 4-mm zone ("uptake zone") and minimal - within a 8-mm zone ("equalization zone"). In all patients, despite the presence of induced astigmatism and residual myopia (0.83+/-0.09 diopters in average), distance visual acuity was high enough without an additional correction (0.82+/-0.05 in average). Apparently, in these patients the aberrations (astigmatism in particular) exceed the focal depth.

  3. [Results of corneal and total astigmatism estimation by different methods in myopic patients wearing orthokeratology contact lenses].

    PubMed

    Tarutta, E P; Aliaeva, O O; Verzhanskaia, T Iu; Milash, S V

    2013-01-01

    Reports have been made that corneal aberrations of all orders, including astigmatism, often significantly increase with the use of night orthokeratology lenses. In this study the dynamic changes of total and corneal astigmatism in myopes using orthokeratology lenses was evaluated by different methods. The study enrolled 38 patients (76 eyes) with low and medium myopia (28 and 48 eyes correspondingly) and initial astigmatism less than 2 diopters. The assessment was made before and in different terms after the patient started to wear orthokeratology lenses. Induced astigmatism (> or =1 diopter) was found in more than 50% of cases. The degree of astigmatism gradually increased from the centre to the periphery within the papillary zone. The maximum values were found within a 4-mm zone ("uptake zone") and minimal - within a 8-mm zone ("equalization zone"). In all patients, despite the presence of induced astigmatism and residual myopia (0.83+/-0.09 diopters in average), distance visual acuity was high enough without an additional correction (0.82+/-0.05 in average). Apparently, in these patients the aberrations (astigmatism in particular) exceed the focal depth. PMID:24137984

  4. Optimum form of posterior chamber intraocular lenses to minimize aberrational astigmatism.

    PubMed

    Takei, K; Hommura, S; Okajima, H

    1995-01-01

    To optically determine the optimum form for a posterior chamber intraocular lens (PC IOL), we calculated the aberrational astigmatism induced by tilt and decentration of the PCIOL using an exact raytracing. First, the position and the radii of curvatures of the IOL were determined to make an emmetropic eye model using a paraxial raytracing. Next, the chief rays originating from the fovea centralis were traced backward through the tilted and/or decentrated PC IOL, the center of the pupil and the cornea, using trigonometric raytracing. Finally, the maximum and minimum aberrational astigmatism were calculated based on the Coddington's Equations for the sagittal and the tangential foci of the ray. All the refractive parameters in Gullstrand's No. 1 schematic eye were adopted. The effect of varying anterior corneal asphericity on the results was also examined. Four forms of polymethylmethacrylate PC IOLs (refractive index: 1.491) were analyzed; a plano-convex IOL with the curved surface facing the cornea, and three bi-convex forms with the ratio of anterior-to-posterior radii of curvatures of 1:4, 1:2 and 1:1, respectively. The 1:4 bi-convex form showed the lowest values for the maximum aberrational astigmatism calculated at every combination of tilt and decentration except 0 degrees tilt and/or 0 mm decentration. The aberrational astigmatism with the 1:4 bi-convex form of PC IOL did not exceed 1.0 D at the maximum tilt and decentration. The variation of anterior corneal asphericity did not influence the results. We conclude that the 1:4 bi-convex form of PC IOL minimizes the postoperative astigmatism induced by tilt and/or decentration of the lens. PMID:8926647

  5. Identifying differentially expressed genes in trophozoites and cysts of Acanthamoeba T4 genotype: Implications for developing new treatments for Acanthamoeba keratitis.

    PubMed

    Abedkhojasteh, Hoda; Niyyati, Maryam; Rezaei, Sasan; Mohebali, Mehdi; Farnia, Shohreh; Kazemi-Rad, Elham; Roozafzoon, Reza; Sianati, Hamed; Rezaeian, Mostafa; Heidari, Mansour

    2015-02-01

    Acanthamoeba T4 genotype is the most prevalent genotype associated with amoebic keratitis. Acanthamoeba keratitis therapy is difficult due to transformation of trophozoite to cyst stage, which hinders the treatment of the disease. Although encystation assists the organism to survive against the chemotherapeutic compounds, the precise mechanism of encystation remains poorly understood. The purpose of this work was to identify differentially expressed genes in Acanthamoeba T4 genotype which might be useful for understanding of the encystment process and may thus help develop more efficient treatment. The mRNA profile of trophozoite and cyst of Acanthamoeba T4 genotype isolated from a soft contact lens wearer were analyzed using a cDNA amplified fragment length polymorphism (cDNA-AFLP) technique. Subsequently, a real time reverse transcriptase-PCR was performed to validate the cDNA-AFLP results. Three genes, heat shock protein70 (hsp70), actin-I and elongation factor-1alpha (EF-1α) were differentially expressed during Acanthamoeba differentiation. An in silico result predicted that transformation of trophozoite to cyst could be mediated through their cooperation with the protein partners interaction. Taken together, our experimental and bioinformatics findings suggested potential functions of hsp70, EF-1α and actin-I in differentiation of Acanthamoeba T4 genotype which may be useful in the design of an efficient therapeutic strategy in AK.

  6. Mechanisms associated with phagocytosis of Arcobacter butzleri by Acanthamoeba castellanii.

    PubMed

    Medina, Gustavo; Flores-Martin, Sandra; Fonseca, Belchiolina; Otth, Carola; Fernandez, Heriberto

    2014-05-01

    Acanthamoeba castellanii is a free-living amoeba widely found in environmental matrices such as soil and water. Arcobacter butzleri is an emerging potential zoonotic pathogen that can be isolated from environmental water sources, where they can establish endosymbiotic relationships with amoebas. The aim of this study was to describe the implication of mannose-binding proteins and membrane-associated receptors of glucose and galactose present in the amoebic membrane, during the attachment of Arcobacter butzleri by blocking with different saccharides. Another objective was to describe the signaling pathways involved in phagocytosis of these bacteria using specific inhibitors and analyze the implication of phagolysosome formation on the survival of Arcobacter butzleri inside the amoeba. We infer that the attachment of Arcobacter butzleri to the amoeba is a process which involves the participation of mannose-binding proteins and membrane-associated receptors of glucose and galactose present in the amoeba. We also demonstrated an active role of protozoan actin polymerization in the phagocytosis of Arcobacter butzleri and a critical involvement of PI3K and RhoA pathways. Further, we demonstrated that the tyrosine kinase-induced actin polymerization signal is essential in Acanthamoeba-mediated bacterial uptake. Through phagolysosomal formation analysis, we conclude that the survival of Arcobacter butzleri inside the amoeba could be related with the ability to remain inside vacuoles not fused with lysosomes, or with the ability to retard the fusion between these structures. All these results help the understanding of the bacterial uptake mechanisms used by Acanthamoeba castellanii and contribute to evidence of the survival mechanisms of Arcobacter butzleri.

  7. Artemether Exhibits Amoebicidal Activity against Acanthamoeba castellanii through Inhibition of the Serine Biosynthesis Pathway

    PubMed Central

    Deng, Yihong; Ran, Wei; Man, Suqin; Li, Xueping; Gao, Hongjian; Tang, Wei

    2015-01-01

    Acanthamoeba sp. parasites are the causative agents of Acanthamoeba keratitis, fatal granulomatous amoebic encephalitis, and cutaneous infections. However, there are currently no effective drugs for these organisms. Here, we evaluated the activity of the antimalarial agent artemether against Acanthamoeba castellanii trophozoites and identified potential targets of this agent through a proteomic approach. Artemether exhibited in vitro amoebicidal activity in a time- and dose-dependent manner and induced ultrastructural modification and cell apoptosis. The iTRAQ quantitative proteomic analysis identified 707 proteins that were differentially expressed after artemether treatment. We focused on phosphoglycerate dehydrogenase and phosphoserine aminotransferase in the serine biosynthesis pathway because of their importance to the growth and proliferation of protozoan and cancer cells. The expression of these proteins in Acanthamoeba was validated using quantitative real-time PCR and Western blotting after artemether treatment. The changes in the expression levels of phosphoserine aminotransferase were consistent with those of phosphoglycerate dehydrogenase. Therefore, the downregulation of phosphoserine aminotransferase may be due to the downregulation of phosphoglycerate dehydrogenase. Furthermore, exogenous serine might antagonize the activity of artemether against Acanthamoeba trophozoites. These results indicate that the serine biosynthesis pathway is important to amoeba survival and that targeting these enzymes would improve the treatment of Acanthamoeba infections. Artemether may be used as a phosphoglycerate dehydrogenase inhibitor to control or block Acanthamoeba infections. PMID:26014935

  8. Abietane diterpenoids from Salvia sclarea transformed roots as growth inhibitors of pathogenic Acanthamoeba spp.

    PubMed

    Kuźma, Łukasz; Derda, Monika; Hadaś, Edward; Wysokińska, Halina

    2015-01-01

    Amoebae from the genus Acanthamoeba are known agents leading to various diseases such as granulomatous amoebic encephalitis (GAE), a chronic progressive disease of the central nervous system, amoebic keratitis (AK), chronic eye infection, amoebic pneumitis (AP), chronic lung infection, and skin infections. It is known that various synthetic anti-Acanthamoeba substances are ineffective. Therefore, other substances, e.g., natural plant compounds, are the focus of biological investigations regarding anti-parasite activity. In this work, the ability of four abietane diterpenoids (ferruginol, salvipisone, aethiopinone, and 1-oxo-aethiopinone) to inhibit Acanthamoeba growth is reported. All investigated compounds were active against Acanthamoeba growing in vitro. Among them, ferruginol demonstrated the highest activity against Acanthamoeba. This compound inhibited Acanthamoeba growth by about 72% in a 3-day exposure period (IC50 17.45 μM), while aethiopinone and 1-oxo-aethiopinone demonstrated this activity at the level of 55-56%. Salvipisone reduced the growth of Acanthamoeba in vitro culture by 39%. For this compound, the value of IC50 was 701.94 μM after 72 h of exposure.

  9. Susceptibility of Acanthamoeba castellanii to contact lens disinfecting solutions.

    PubMed

    Zanetti, S; Fiori, P L; Pinna, A; Usai, S; Carta, F; Fadda, G

    1995-07-01

    A corneal isolate of Acanthamoeba castellanii was exposed to commercial contact lens disinfecting solutions containing hydrogen peroxide, benzalkonium chloride, polyaminopropyl biguanide, polyquaternium 1, and chlorhexidine-thimerosal. The minimum trophozoite amebicidal concentration and exposure times required to kill trophozoites and cysts were determined. Solutions containing hydrogen peroxide or chlorhexidine-thimerosal were active against both trophozoites and cysts. The benzalkonium chloride-based solution was effective only against trophozoites. Solutions containing polyaminopropyl biguanide or polyquaternium 1 were completely ineffective. The need for adequate exposure times must be stressed.

  10. Susceptibility of Acanthamoeba castellanii to contact lens disinfecting solutions.

    PubMed Central

    Zanetti, S; Fiori, P L; Pinna, A; Usai, S; Carta, F; Fadda, G

    1995-01-01

    A corneal isolate of Acanthamoeba castellanii was exposed to commercial contact lens disinfecting solutions containing hydrogen peroxide, benzalkonium chloride, polyaminopropyl biguanide, polyquaternium 1, and chlorhexidine-thimerosal. The minimum trophozoite amebicidal concentration and exposure times required to kill trophozoites and cysts were determined. Solutions containing hydrogen peroxide or chlorhexidine-thimerosal were active against both trophozoites and cysts. The benzalkonium chloride-based solution was effective only against trophozoites. Solutions containing polyaminopropyl biguanide or polyquaternium 1 were completely ineffective. The need for adequate exposure times must be stressed. PMID:7492111

  11. Acanthamoeba castellanii: identification and distribution of actin cytoskeleton.

    PubMed

    González-Robles, Arturo; Castañón, Guadalupe; Hernández-Ramírez, Verónica Ivonne; Salazar-Villatoro, Lizbeth; González-Lázaro, Mónica; Omaña-Molina, Maritza; Talamás-Rohana, Patricia; Martínez-Palomo, Adolfo

    2008-07-01

    The presence of the cytoskeleton of Acanthamoeba castellanii was observed by means of cryo-electronmicroscopy and immunofluorescence techniques. This structure is formed largely by fibers and networks of actin located mainly in cytoplasmic locomotion structures as lamellipodia and as well as in various endocytic structures. In addition, the comparison between total actin content in whole extracts among different amoebae was made. The molecular weight of actin in A. castellanii was 44 kDa, and 45 kDa for Naegleria fowleri and Entamoeba histolytica.

  12. The use of toric intraocular lens to correct astigmatism at the time of cataract surgery

    PubMed Central

    Khan, Mohammad I.; Ch’ng, Soon W.; Muhtaseb, Mohammed

    2015-01-01

    Background: To evaluate the visual and refractive outcomes of cataract surgery with toric intraocular lens (IOL) implantation at a teaching hospital of the United Kingdom. Design: Prospective interventional case series. Materials and Methods: This study compared the outcome of 3 groups of patients: Group 1 included 25 eyes with cataract and more than 2.5 diopters (D) of corneal astigmatism receiving a toric monofocal IOL; Group 2 had 18 patients with cataract and more than 2.5 D of astigmatism but receiving a non-toric monofocal IOL; while Group 3 had 25 patients with cataract and less than 1.5 D of astigmatism and receiving a non-toric monofocal IOL. Data collected included uncorrected (UDVA) and corrected (CDVA) distance visual acuities, refraction and corneal keratometry. Postoperative examinations were scheduled at 1 and 6 weeks. Results: Postoperatively the mean UDVA was LogMAR 0.27 ± 0.20 (equivalent snellen acuity of 20/37) in Group 1, 0.54 ± 0.22 (20/69) in Group 2 and 0.16 ± 0.20 (20/29) in Group 3. The mean CDVA was LogMAR 0.08 ± 0.13 (20/24) in Group 1, 0.23 ± 0.16 (20/34) in Group 2 and 0.04 ± 0.13 in Group 3 (20/22). The mean preoperative keratometric cylinder was 3.78 ± 1.0 D in Group 1, 3.41 ± 1.47 D in Group 2 and 0.97 ± 0.43D in Group 3; the mean postoperative subjective cylinder was 1.2 ± 0.68 D in Group 1, 3.23 ± 1.41 D in Group 2 and 0.95 ± 0.58 D in Group 3. The difference was statistically significant for the postoperative refractive cylinder values when comparing Group 1 to Group 2 (P = <0.0001) but the difference was insignificant between Group 1 and Group 3 (P = 0.23). Conclusion: Toric IOL implantation is an effective option to manage corneal astigmatism at the time of cataract surgery and to optimise visual outcomes for astigmatic patients when comparing to outcomes for their non-astigmatic counterparts. PMID:25709273

  13. Extended depth of focus intra-ocular lens: a solution for presbyopia and astigmatism

    NASA Astrophysics Data System (ADS)

    Zlotnik, Alex; Raveh, Ido; Ben Yaish, Shai; Yehezkel, Oren; Belkin, Michael; Zalevsky, Zeev

    2010-02-01

    Purpose: Subjects after cataract removal and intra-ocular lens (IOL) implantation lose their accommodation capability and are left with a monofocal visual system. The IOL refraction and the precision of the surgery determine the focal distance and amount of astigmatic aberrations. We present a design, simulations and experimental bench testing of a novel, non-diffractive, non-multifocal, extended depth of focus (EDOF) technology incorporated into an IOL that allows the subject to have astigmatic and chromatic aberrations-free continuous focusing ability from 35cm to infinity as well as increased tolerance to IOL decentration. Methods: The EDOF element was engraved on a surface of a monofocal rigid IOL as a series of shallow (less than one micron deep) concentric grooves around the optical axis. These grooves create an interference pattern extending the focus from a point to a length of about one mm providing a depth of focus of 3.00D (D stands for Diopters) with negligible loss of energy at any point of the focus while significantly reducing the astigmatic aberration of the eye and that generated during the IOL implantation. The EDOF IOL was tested on an optical bench simulating the eye model. In the experimental testing we have explored the characteristics of the obtained EDOF capability, the tolerance to astigmatic aberrations and decentration. Results: The performance of the proposed IOL was tested for pupil diameters of 2 to 5mm and for various spectral illuminations. The MTF charts demonstrate uniform performance of the lens for up to 3.00D at various illumination wavelengths and pupil diameters while preserving a continuous contrast of above 25% for spatial frequencies of up to 25 cycles/mm. Capability of correcting astigmatism of up to 1.00D was measured. Conclusions: The proposed EDOF IOL technology was tested by numerical simulations as well as experimentally characterized on an optical bench. The new lens is capable of solving presbyopia and astigmatism

  14. Acanthamoeba spp. in Contact Lenses from Healthy Individuals from Madrid, Spain

    PubMed Central

    Gomes, Thiago dos Santos; Magnet, Angela; Izquierdo, Fernando; Vaccaro, Lucianna; Redondo, Fernando; Bueno, Sara; Sánchez, Maria Luisa; Angulo, Santiago; Fenoy, Soledad; Hurtado, Carolina; del Aguila, Carmen

    2016-01-01

    Purpose Acanthamoeba keratitis (AK) is a painful and potentially blinding corneal infection caused by Acanthamoeba spp. In Madrid, environmental studies have demonstrated a high presence of these free-living amoebae in tap water. Since most of AK cases occur in contact lenses (CL) wearers with inadequate hygiene habits, the presence of Acanthamoeba in discarded CL has been studied and compared with other common etiological agents of keratitis, such as Pseudomonas aeruginosa and Staphylococcus aureus. Methods One hundred and seventy-seven healthy individuals from Madrid contributed their discarded CL and answered a questionnaire on hygiene habits. DNA was extracted from the CL solution and analyzed by real-time PCR for Acanthamoeba, Pseudomonas aeruginosa and Staphylococcus aureus. These CL and their solutions were also cultured on non-nutrient agar to isolate Acanthamoeba. Results Among the 177 samples, Acanthamoeba DNA was detected in 87 (49.2%), P. aeruginosa DNA in 14 (7.9%) and S. aureus DNA in 19 (10.7%). Cultivable amoebae, however, were observed in only one sample (0.6%). This isolate was genotyped as T4. The habits reported by this CL owner included some recognized risk factors for AK, but in this study only the practice of “not cleaning the CL case” presented some statistical significant association with Acanthamoeba DNA presence. Detection of the investigated bacterial DNA did not demonstrate statistical significant association with the studied practices, but the presence of P. aeruginosa revealed a possible inhibition of Acanthamoeba in these samples. Conclusions The PCR results suggest a high presence of Acanthamoeba spp. in healthy CL wearers from Madrid, but we can assume that CL solutions are properly disinfecting the CL since only 1.1% of the positive PCR samples correspond to viable amoebae and, after four years, only one participant reported stronger ocular problems. Nevertheless, more studies are necessary to corroborate this hypothesis. PMID

  15. Pathogenic and nonpathogenic Acanthamoeba spp. in thermally polluted discharges and surface waters

    SciTech Connect

    de Jonckheere, J.F.

    1981-02-01

    During spring and autumn, the total number of amoebae and the number of acanthamoeba species able to grow at 37 degrees C were determined in six thermally polluted factory discharges and the surrounding surface waters. The isolated Acanthamoeba strains were studied for growth in axenic medium, cytopathic effect in Vito cell cultures, and virulence in mice. Although more amoebae were isolated in autumn, the number of Acanthamoeba species was lower than in spring, when the percent of pathogenic strains among the isolates was highest. Higher concentrations of amoebae were found in warm discharges, and more virulent strains occurred in thermal discharges than in surface waters.

  16. Acanthamoeba differentiation: a two-faced drama of Dr Jekyll and Mr Hyde.

    PubMed

    Siddiqui, Ruqaiyyah; Dudley, Ricky; Khan, Naveed Ahmed

    2012-06-01

    The ability of cyst-forming protists such as Acanthamoeba to escape death by transforming into a cyst form, that is resistant to harsh physiological, environmental and pharmacological conditions, has continued to pose a serious challenge to human and animal health. A complete understanding of the fundamental principles of genome evolution and biochemical pathways of cellular differentiation offers unprecedented opportunities to counter detrimental outcomes. Acanthamoeba can elude inhospitable conditions by forming cysts. Here we unravel the processes involved in the phenotypic switching of Acanthamoeba, which are critical in our efforts to find potential targets for chemotherapy. PMID:22309612

  17. Acanthamoeba differentiation: a two-faced drama of Dr Jekyll and Mr Hyde.

    PubMed

    Siddiqui, Ruqaiyyah; Dudley, Ricky; Khan, Naveed Ahmed

    2012-06-01

    The ability of cyst-forming protists such as Acanthamoeba to escape death by transforming into a cyst form, that is resistant to harsh physiological, environmental and pharmacological conditions, has continued to pose a serious challenge to human and animal health. A complete understanding of the fundamental principles of genome evolution and biochemical pathways of cellular differentiation offers unprecedented opportunities to counter detrimental outcomes. Acanthamoeba can elude inhospitable conditions by forming cysts. Here we unravel the processes involved in the phenotypic switching of Acanthamoeba, which are critical in our efforts to find potential targets for chemotherapy.

  18. Pathogenic and nonpathogenic Acanthamoeba spp. in thermally polluted discharges and surface waters.

    PubMed

    de Jonckheere, J F

    1981-02-01

    During spring and autumn, the total number of amoebae and the number of acanthamoeba species able to grow at 37 degrees C were determined in six thermally polluted factory discharges and the surrounding surface waters. The isolated Acanthamoeba strains were studied for growth in axenic medium, cytopathic effect in Vero cell cultures, and virulence in mice. Although more amoebae were isolated in autumn, the number of Acanthamoeba species was lower than in spring, when the percent of pathogenic strains among the isolates was highest. Higher concentrations of amoebae were found in warm discharges, and more virulent strains occurred in thermal discharges than in surface waters.

  19. New long chain bases in lipophosphonoglycan of Acanthamoeba castellanii.

    PubMed

    Karaś, Magdalena A; Russa, Ryszard

    2013-06-01

    The polymer called lipophosphonoglycan (LPG) was isolated from Acanthamoeba castellanii membranes after exhaustive delipidation and butanol extraction. A novel extremely long phytosphingosine was revealed in glycoinositolphosphosphingolipid (GIPSL). All data obtained by gas-liquid chromatography coupled with MS analyses of products liberated during acid methanolysis and products of sodium metaperiodate and permanganate-periodate oxidations showed an unusual pattern of long chain bases (LCB) with branched bases (anteiso-C₂₄, anteiso-C₂₅, anteiso-C₂₆, iso-C₂₆, anteiso-C₂₇, and anteiso-C28) and normal ones (C₂₄, C₂₅, C₂₆, C₂₇). The phytosphingosines with hexa-, hepta-, and octacosanoic chains have not been detected in Acanthamoeba cells up to now. Also, the isomer configuration of long chain bases in LPG of A. castellanii was not defined in earlier reports. In the GC-MS chromatograms, the component forming a peak corresponding to anteiso-C₂₅ phytosphingosine was the most abundant and constituted more than 50 % of all LCB.

  20. [Amoebic meningoencephalitis by "Eaegleria" and "Acanthamoeba" (author's transl)].

    PubMed

    de Carneri, I

    1977-01-01

    Primary amoebic meningoencephalitis (ME) by Naegleria fowleri a free-living protozoon found in fresh, warm waters, is a well known fatal disease lasting less than one week. It affects sporadically swimmers and children playing in mud puddles. Less than 100 cases have been described. Recently a more rare, distinct amoebic meningoencephalitis due to some species of free-living Acanthamoeba was identified, lasting some weeks or more but still with a fatal evolution. In this case the amoebae do not always enter the brain directly through the cribrous membranes but cause mild, primary infections of respiratory airways: exceptionally, mainly in immunodepressed subjects, they then reach the CNS causing a secondary ME. Naegleria is fairly sensitive in vitro to some drugs, but in vivo their efficacy is dramtically lowered for pharmacokinetic reasons. Acanthamoeba is in every respect less sensitive. Prophylaxis is almost impossible to achieve. Some diagnostic procedures are described and the importance of their use in diagnosis of the so called aseptic purulent ME is stressed. PMID:616244

  1. Autophagy protein 8 mediating autophagosome in encysting Acanthamoeba.

    PubMed

    Moon, Eun-Kyung; Chung, Dong-Il; Hong, Yeon-Chul; Kong, Hyun-Hee

    2009-11-01

    Autophagy is an evolutionally conserved protein degradation pathway in eukaryotes. It plays essential roles during starvation, cellular differentiation, cell death, and aging by eliminating unwanted or unnecessary organelles and recycling the components for reuse. ATG8, a member of a novel ubiquitin-like protein family, is an essential component of the autophagic machinery. The present study identified and characterized autophagy protein 8 in Acanthamoeba castellanii an amphizoic amoeba causing granulomatous amoebic encephalitis and amoebic keratitis in humans. Real-time polymerase chain reaction demonstrated that the A. castellanii Atg8 (AcAtg8) gene encoding a 118 amino acid protein was highly expressed during encystation. Fluorescence microscopic analysis following transient transfection of enhanced green fluorescent protein-AcAtg8 revealed small or large vacuolar fluorescent structures in an encysting amoeba. The Atg8 fluorescent structures on the membrane were identified as autophagosomes by co-localization analysis with LysoTracker. Chemically synthesized small interfering RNA against AcAtg8 reduced the encystation efficiency and inhibited autophagosome formation in Acanthamoeba. PMID:19560492

  2. Proteomic profiling of the infective trophozoite stage of Acanthamoeba polyphaga.

    PubMed

    Caumo, Karin Silva; Monteiro, Karina Mariante; Ott, Thiely Rodrigues; Maschio, Vinicius José; Wagner, Glauber; Ferreira, Henrique Bunselmeyer; Rott, Marilise Brittes

    2014-12-01

    Acanthamoeba polyphaga is a free-living protozoan pathogen, whose infective trophozoite form is capable of causing a blinding keratitis and fatal granulomatous encephalitis in humans. The damage caused by A. polyphaga trophozoites in human corneal or brain infections is the result of several different pathogenic mechanisms that have not yet been elucidated at the molecular level. We performed a comprehensive analysis of the proteins expressed by A. polyphaga trophozoites, based on complementary 2-DE MS/MS and gel-free LC-MS/MS approaches. Overall, 202 non-redundant proteins were identified. An A. polyphaga proteomic map in the pH range 3-10 was produced, with protein identification for 184 of 370 resolved spots, corresponding to 142 proteins. Additionally, 94 proteins were identified by gel-free LC-MS/MS. Functional classification revealed several proteins with potential importance for pathogen survival and infection of mammalian hosts, including surface proteins and proteins related to defense mechanisms. Our study provided the first comprehensive proteomic survey of the trophozoite infective stage of an Acanthamoeba species, and established foundations for prospective, comparative and functional studies of proteins involved in mechanisms of survival, development, and pathogenicity in A. polyphaga and other pathogenic amoebae.

  3. Thermal correction of astigmatism in the gravitational wave observatory GEO 600

    NASA Astrophysics Data System (ADS)

    Wittel, H.; Lück, H.; Affeldt, C.; Dooley, K. L.; Grote, H.; Leong, J. R.; Prijatelj, M.; Schreiber, E.; Slutsky, J.; Strain, K.; Was, M.; Willke, B.; Danzmann, K.

    2014-03-01

    The output port of GEO 600 is dominated by unwanted higher order modes (HOMs). The current thermal actuation system, a ring heater behind one of the folding mirrors, causes a significant amount of astigmatism, which produces HOMs. We have built and installed an astigmatism correction system, based on heating this folding mirror at the sides (laterally). With these side heaters and the ring heater behind the mirror, it is possible to tune its radius of curvature in the horizontal and the vertical degree of freedom. We use this system to match the mirrors in the two arms of GEO 600 to each other, thereby reducing the contrast defect. The use of the side heaters reduces the power of the HOMs at the output of GEO 600 by approximately 37%.

  4. Autorefraction, Retinoscopy, Javal's Rule, and Grosvenor's Modified Javal's Rule: The Best Predictor of Refractive Astigmatism

    PubMed Central

    Asiedu, Kofi; Ampiah, Emmanuel Ekow

    2016-01-01

    The aim of the study was to determine the level of agreement between Javal's rule, autorefraction, retinoscopy, and refractive astigmatism and to determine which technique is the most suitable substitute when subjective refraction is not applicable using a clinical sample. A total of 36 subjects, 14 males and 22 females, were involved in this study. The intraclass correlation coefficients between subjective refraction, autorefraction, and retinoscopy were 0.895 and 0.989, respectively, for the spherical equivalent. The Bland-Altman 95% limits of agreement between subjective refraction and autorefraction; subjective refraction and retinoscopy; and autorefraction and retinoscopy were −2.84 to 3.58, −0.88 to 1.12, and −3.01 to 3.53, respectively, for the spherical equivalent. The intraclass correlation coefficients between spectacle total astigmatism and the following techniques were as follows: retinoscopy (0.85); autorefraction (0.92); Javal's rule (0.82); and Grosvenor et al. version (0.85). The Bland-Altman 95% limits of agreement between subjective refraction and autorefraction; subjective refraction and retinoscopy; subjective refraction and Javal's rule; and subjective refraction and Grosvenor et al. version were −0.87 to 1.25, −1.49 to 1.99, −0.73 to 1.93, and −0.89 to 1.7, respectively, for the total astigmatism. The study showed that autorefraction and Javal's rule may provide a starting point for subjective refraction cylinder power determination but only retinoscopy may satisfactorily replace subjective refraction total astigmatism when subjective refraction is not applicable. PMID:27803811

  5. The approximate analysis of the electromagnetic characters of 3-D radome by complex astigmatic wave theory

    NASA Astrophysics Data System (ADS)

    Wang, Yueqing; Wu, Guisheng; Chen, Zhenyang

    The complex astigmatic wave, which imitates the 3-D beam in high-frequency, is an effective method to analyze the electromagnetic characters of the 3-D arbitrarily curved radome. A number of calculations for the ellipsoidal sandwich radome are performed, and the stereoscopic graphics of the results are constructed. Comparing with the experiments, it is shown that this method can be used to simplify analysis and optimization design for many kinds of 3-D radome.

  6. [Optimization of broad-band flat-field holographic concave grating without astigmatism].

    PubMed

    Kong, Peng; Tang, Yu-guo; Bayanheshig; Li, Wen-hao; Cui, Jin-jiang

    2012-02-01

    The desirable imaging locations of the flat-field holographic concave gratings should be in a plane. And the object can be imaged perfectly by the grating when the tangential focal curve and sagittal focal curve both superpose the intersection of the image plane and dispersion plane. But actually, the defocus can not be eliminated over the entire wavelength range, while the astigmatism vanishes when the grating parameters satisfy some conditions. An optimization method for broad-band flat-field holographic concave gratings with absolute astigmatism correction was proposed. The ray tracing software ZEMAX was used for investigating the imaging properties of the grating. And we made a comparison between spectral performance of gratings designed by this new method and that by conventional method, respectively. The results indicated that the spectral performance of gratings designed by using the absolute astigmatism correction method can be as good as gratings designed with the conventional method. And the focusing performance in the sagittal direction is much better, so that the S/N ratio can be greatly improved.

  7. Polar Value Analysis of Corneal Astigmatism in Intrastromal Corneal Ring Segment Implantation

    PubMed Central

    Rho, Chang Rae; Kim, Min-Ji

    2016-01-01

    Purpose. To evaluate surgically induced astigmatism (SIA) and the average corneal power change in symmetric intrastromal corneal ring segment (ICRS) implantation. Methods. The study included 34 eyes of 34 keratoconus patients who underwent symmetric Intacs SK ICRS implantation. The corneal pocket incision meridian was the preoperative steep meridian. Corneal power data were obtained before and 3 months after Intacs SK ICRS implantation using scanning-slit topography. Polar value analysis was used to evaluate the SIA. Hotelling's trace test was used to compare intraindividual changes. Results. Three months postoperatively, the combined mean polar value for SIA changed significantly (Hotelling's T2 = 0.375; P = 0.006). The SIA was 1.54 D at 99° and the average corneal power decreased significantly by 3.8 D. Conclusion. Intacs SK ICRS placement decreased the average corneal power and corneal astigmatism compared to the preoperative corneal power and astigmatism when the corneal pocket incision was made at the preoperative steep meridian. PMID:27795856

  8. Azole Antifungal Agents To Treat the Human Pathogens Acanthamoeba castellanii and Acanthamoeba polyphaga through Inhibition of Sterol 14α-Demethylase (CYP51)

    PubMed Central

    Lamb, David C.; Warrilow, Andrew G. S.; Rolley, Nicola J.; Parker, Josie E.; Nes, W. David; Smith, Stephen N.; Kelly, Diane E.

    2015-01-01

    In this study, we investigate the amebicidal activities of the pharmaceutical triazole CYP51 inhibitors fluconazole, itraconazole, and voriconazole against Acanthamoeba castellanii and Acanthamoeba polyphaga and assess their potential as therapeutic agents against Acanthamoeba infections in humans. Amebicidal activities of the triazoles were assessed by in vitro minimum inhibition concentration (MIC) determinations using trophozoites of A. castellanii and A. polyphaga. In addition, triazole effectiveness was assessed by ligand binding studies and inhibition of CYP51 activity of purified A. castellanii CYP51 (AcCYP51) that was heterologously expressed in Escherichia coli. Itraconazole and voriconazole bound tightly to AcCYP51 (dissociation constant [Kd] of 10 and 13 nM), whereas fluconazole bound weakly (Kd of 2,137 nM). Both itraconazole and voriconazole were confirmed to be strong inhibitors of AcCYP51 activity (50% inhibitory concentrations [IC50] of 0.23 and 0.39 μM), whereas inhibition by fluconazole was weak (IC50, 30 μM). However, itraconazole was 8- to 16-fold less effective (MIC, 16 mg/liter) at inhibiting A. polyphaga and A. castellanii cell proliferation than voriconazole (MIC, 1 to 2 mg/liter), while fluconazole did not inhibit Acanthamoeba cell division (MIC, >64 mg/liter) in vitro. Voriconazole was an effective inhibitor of trophozoite proliferation for A. castellanii and A. polyphaga; therefore, it should be evaluated in trials versus itraconazole for controlling Acanthamoeba infections. PMID:26014948

  9. Down-regulation of cellulose synthase inhibits the formation of endocysts in Acanthamoeba.

    PubMed

    Moon, Eun-Kyung; Hong, Yeonchul; Chung, Dong-Il; Goo, Youn-Kyoung; Kong, Hyun-Hee

    2014-04-01

    Acanthamoeba cysts are resistant to unfavorable physiological conditions and various disinfectants. Acanthamoeba cysts have 2 walls containing various sugar moieties, and in particular, one third of the inner wall is composed of cellulose. In this study, it has been shown that down-regulation of cellulose synthase by small interfering RNA (siRNA) significantly inhibits the formation of mature Acanthamoeba castellanii cysts. Calcofluor white staining and transmission electron microscopy revealed that siRNA transfected amoeba failed to form an inner wall during encystation and thus are likely to be more vulnerable. In addition, the expression of xylose isomerase, which is involved in cyst wall formation, was not altered in cellulose synthase down-regulated amoeba, indicating that cellulose synthase is a crucial factor for inner wall formation by Acanthamoeba during encystation.

  10. Juglone induces cell death of Acanthamoeba through increased production of reactive oxygen species.

    PubMed

    Jha, Bijay Kumar; Jung, Hui-Jung; Seo, Incheol; Suh, Seong-Il; Suh, Min-Ho; Baek, Won-Ki

    2015-12-01

    Juglone (5-hydroxy-1,4-naphthoquinone) is a major chemical constituent of Juglans mandshruica Maxim. Recent studies have demonstrated that juglone exhibits anti-cancer, anti-bacterial, anti-viral, and anti-parasitic properties. However, its effect against Acanthamoeba has not been defined yet. The aim of this study was to investigate the effect of juglone on Acanthamoeba. We demonstrate that juglone significantly inhibits the growth of Acanthamoeba castellanii at 3-5 μM concentrations. Juglone increased the production of reactive oxygen species (ROS) and caused cell death of A. castellanii. Inhibition of ROS by antioxidant N-acetyl-l-cysteine (NAC) restored the cell viability. Furthermore, our results show that juglone increased the uptake of mitochondrial specific dye. Collectively, these results indicate that ROS played a significant role in the juglone-induced cell death of Acanthamoeba.

  11. Juglone induces cell death of Acanthamoeba through increased production of reactive oxygen species.

    PubMed

    Jha, Bijay Kumar; Jung, Hui-Jung; Seo, Incheol; Suh, Seong-Il; Suh, Min-Ho; Baek, Won-Ki

    2015-12-01

    Juglone (5-hydroxy-1,4-naphthoquinone) is a major chemical constituent of Juglans mandshruica Maxim. Recent studies have demonstrated that juglone exhibits anti-cancer, anti-bacterial, anti-viral, and anti-parasitic properties. However, its effect against Acanthamoeba has not been defined yet. The aim of this study was to investigate the effect of juglone on Acanthamoeba. We demonstrate that juglone significantly inhibits the growth of Acanthamoeba castellanii at 3-5 μM concentrations. Juglone increased the production of reactive oxygen species (ROS) and caused cell death of A. castellanii. Inhibition of ROS by antioxidant N-acetyl-l-cysteine (NAC) restored the cell viability. Furthermore, our results show that juglone increased the uptake of mitochondrial specific dye. Collectively, these results indicate that ROS played a significant role in the juglone-induced cell death of Acanthamoeba. PMID:26358271

  12. Use of a Toric Intraocular Lens and a Limbal-Relaxing Incision for the Management of Astigmatism in Combined Glaucoma and Cataract Surgery

    PubMed Central

    Gibbons, Allister

    2016-01-01

    Purpose We report the surgical management of a patient with glaucoma undergoing cataract surgery with high preexisting astigmatism. A combination of techniques was employed for her astigmatism management. Methods A 76-year-old female with 5.5 dpt of corneal astigmatism underwent surgery in her left eye consisting of one-site trabeculectomy, phacoemulsification, toric intraocular lens implantation and a single inferior limbal-relaxing incision. Results Intraocular pressure control was achieved with no medication at 11 mm Hg; before the filtering procedure, the pressure was 16 mm Hg on two topical drugs. Astigmatism was reduced to 0.75 dpt, and both corrected and uncorrected visual acuity improved. Conclusions Astigmatism management can have a good outcome in combined procedures. We encourage surgeons to address astigmatism in the preoperative planning of patients undergoing glaucoma surgery associated with phacoemulsification. PMID:27293408

  13. Detection of Vibrio cholerae and Acanthamoeba species from same natural water samples collected from different cholera endemic areas in Sudan

    PubMed Central

    2011-01-01

    Background Vibrio cholerae O1 and V. cholerae O139 infect humans, causing the diarrheal and waterborne disease cholera, which is a worldwide health problem. V. cholerae and the free-living amoebae Acanthamoeba species are present in aquatic environments, including drinking water and it has shown that Acanthamoebae support bacterial growth and survival. Recently it has shown that Acanthamoeba species enhanced growth and survival of V. cholerae O1 and O139. Water samples from different cholera endemic areas in Sudan were collected with the aim to detect both V. cholerae and Acanthamoeba species from same natural water samples by polymerase chain reaction (PCR). Findings For the first time both V. cholerae and Acanthamoeba species were detected in same natural water samples collected from different cholera endemic areas in Sudan. 89% of detected V. cholerae was found with Acanthamoeba in same water samples. Conclusions The current findings disclose Acanthamoedae as a biological factor enhancing survival of V. cholerae in nature. PMID:21470437

  14. [Encephalitis due to Naegleria and Acanthamoeba. Comparison of organisms and diseases (author's transl)].

    PubMed

    Martinez, A J; Janitschke, K

    1979-04-01

    Naegleria and Acanthamoeba are ubiquitous, free-living amoebas. Infections with Naegleria are acquired nasally by exposure to water and are characterized by an acute fulminant hemorrhagic necrotizing meningoencephalitis leading to death. Acanthamoeba-infections occur in chronically ill, debilitated individuals. A patchy chronic or subacute granulomatous encephalitis is produced by hematogenous spread of the amoebas. The histological or clinical diagnosis is not difficult. PMID:457190

  15. Vectorial role of Acanthamoeba in Legionella propagation in water for human use.

    PubMed

    Magnet, A; Peralta, R H S; Gomes, T S; Izquierdo, F; Fernandez-Vadillo, C; Galvan, A L; Pozuelo, M J; Pelaz, C; Fenoy, S; Del Águila, C

    2015-02-01

    Legionella spp. is the causative agent of Legionnaires' disease and is transmitted through aerosols emanating from man-made water systems. Legionella resistance to water treatments has been related to its association with environmental amoebae such as Acanthamoeba. Due to the high presence of this protozoon in Spain and the high rate of notification of Legionnaires' disease of this country, the aims of this work were to study the coexistence of these bacteria and protozoa in water as well as their interaction. The usefulness of Acanthamoeba co-culture for the isolation of environmental Legionella was also studied. For this purpose, 70 water samples were collected in 2011 from three Drinking Water Treatment Plants, three Wastewater Treatment Plants and five Natural Pools in Spain. Acanthamoeba was found by PCR in 87.1% (61/70) samples and, by culture in 85.7% (60/70) samples. Legionella was detected by PCR in 58.6% (41/70) of water samples, in 5.7% (4/70) by agar culture and 75.7% (53/70) by Acanthamoeba co-culture. From the 54 Acanthamoeba water isolates, Legionella was detected in 43 of them independently of Acanthamoeba's genotype (T3, T4 and T11). Legionella feeleii, Legionella birminghamiensis, Legionella gresilensis/berliardensis, Legionella fairfieldensis, Legionella drozanski and Legionella falloni were identified. In conclusion, our results showed that environmental Acanthamoeba is infected by Legionella to a high percentage, and due to its ubiquity, high resistance and its pathogenic potential per se, new methods for its elimination should be studied. Also, the high effectivity of Acanthamoeba co-culture for Legionella detection has been shown. PMID:25461091

  16. Reevaluation of an Acanthamoeba Molecular Diagnostic Algorithm following an Atypical Case of Amoebic Keratitis

    PubMed Central

    Lau, Rachel; Cunanan, Marlou; Jackson, Jonathan; Ali, Ibne Karim M.; Chong-Kit, Ann; Gasgas, Jason; Tian, Jinfang; Ralevski, Filip

    2015-01-01

    Amoebic keratitis (AK) is a potentially blinding infection, the prompt diagnosis of which is essential for limiting ocular morbidity. We undertook a quality improvement initiative with respect to the molecular detection of acanthamoebae in our laboratory because of an unusual case of discordance. Nine ATCC strains of Acanthamoeba and 40 delinked, biobanked, surplus corneal scraping specimens were analyzed for the presence of acanthamoebae with four separate real-time PCR assays. The assay used by the Free-Living and Intestinal Amebas Laboratory of the CDC was considered the reference standard, and the performance characteristics of each individual assay and pairs of assays were calculated. Outcome measures were sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). Of 49 included specimens, 14 (28.6%) were positive by the gold standard assay, and 35 (71.4%) were negative. The sensitivities of the individual assays ranged from 64.3% to 92.9%, compared to the gold standard, while the specificities ranged from 88.6% to 91.4%. The PPVs and NPVs ranged from 69.2% to 78.6% and from 86.1% to 96.9%, respectively. Combinations of assay pairs led to improved performance, with sensitivities ranging from 92.9% to 100% and specificities ranging from 97.1% to 100%. ATCC and clinical strains of Acanthamoeba that failed to be detected by certain individual assays included Acanthamoeba castellanii, Acanthamoeba culbertsoni, and Acanthamoeba lenticulata. For three clinical specimens, false negativity of the gold standard assay could not be excluded. Molecular diagnostic approaches, especially combinations of highly sensitive and specific assays, offer a reasonably performing, operator-independent, rapid strategy for the detection of acanthamoebae in clinical specimens and are likely to be more practical than either culture or direct microscopic detection. PMID:26202123

  17. Vectorial role of Acanthamoeba in Legionella propagation in water for human use.

    PubMed

    Magnet, A; Peralta, R H S; Gomes, T S; Izquierdo, F; Fernandez-Vadillo, C; Galvan, A L; Pozuelo, M J; Pelaz, C; Fenoy, S; Del Águila, C

    2015-02-01

    Legionella spp. is the causative agent of Legionnaires' disease and is transmitted through aerosols emanating from man-made water systems. Legionella resistance to water treatments has been related to its association with environmental amoebae such as Acanthamoeba. Due to the high presence of this protozoon in Spain and the high rate of notification of Legionnaires' disease of this country, the aims of this work were to study the coexistence of these bacteria and protozoa in water as well as their interaction. The usefulness of Acanthamoeba co-culture for the isolation of environmental Legionella was also studied. For this purpose, 70 water samples were collected in 2011 from three Drinking Water Treatment Plants, three Wastewater Treatment Plants and five Natural Pools in Spain. Acanthamoeba was found by PCR in 87.1% (61/70) samples and, by culture in 85.7% (60/70) samples. Legionella was detected by PCR in 58.6% (41/70) of water samples, in 5.7% (4/70) by agar culture and 75.7% (53/70) by Acanthamoeba co-culture. From the 54 Acanthamoeba water isolates, Legionella was detected in 43 of them independently of Acanthamoeba's genotype (T3, T4 and T11). Legionella feeleii, Legionella birminghamiensis, Legionella gresilensis/berliardensis, Legionella fairfieldensis, Legionella drozanski and Legionella falloni were identified. In conclusion, our results showed that environmental Acanthamoeba is infected by Legionella to a high percentage, and due to its ubiquity, high resistance and its pathogenic potential per se, new methods for its elimination should be studied. Also, the high effectivity of Acanthamoeba co-culture for Legionella detection has been shown.

  18. Standardized Method of Measuring Acanthamoeba Antibodies in Sera from Healthy Human Subjects

    PubMed Central

    Chappell, Cynthia L.; Wright, John A.; Coletta, Michael; Newsome, Anthony L.

    2001-01-01

    Acanthamoeba species can cause serious, debilitating, and sometimes life-threatening infections. Three groups have been identified using morphological and immunological comparisons. Previous serological studies have utilized a variety of antigen preparations and assay methods and reported disparate (3 to 100%) results. This study was designed to (i) optimize an enzyme-linked immunosorbent assay for detecting serum antibodies to each of the Acanthamoeba serogroups and (ii) test 55 healthy individuals for specific immunoglobulin G reactivity. The highest signal-to-background ratio was found when 3,000 fixed, intact trophozoites per well were used with a 1:10 serum dilution. Sera yielding optical densities of <0.25 against all three Acanthamoeba serogroups were used to define the cutoff for positive results. The highest background reactivity with these sera was seen with Acanthamoeba polyphaga (serogroup 2), followed by Acanthamoeba culbertsoni (serogroup 3) and Acanthamoeba astronyxis (serogroup 1). Of 55 subjects tested, the highest number of positive results was seen with A. polyphaga (81.8%), followed by A. astronyxis (52.8%) and A. culbertsoni (40%). Seven serum samples (12.7%) were negative for all three Acanthamoeba serogroups, 16 (29.1%) were positive for one serogroup only, 16 were positive for two serogroups, and 16 reacted to all three serogroups. Further analysis showed no significant associations between serogroup reactivity and age or gender. However, some ethnic differences were noted, especially with A. polyphaga antigens. In that case, serum samples from Hispanic subjects were 14.5 times less likely to be positive (P = 0.0025) and had lower mean absorbance values (P = 0.047) than those from Caucasian subjects. Overall, these data suggest that Acanthamoeba colonization or infection is more common than previously thought. Mild or asymptomatic infections may contribute to the observed serum reactivities. PMID:11427418

  19. Reevaluation of an Acanthamoeba Molecular Diagnostic Algorithm following an Atypical Case of Amoebic Keratitis.

    PubMed

    Lau, Rachel; Cunanan, Marlou; Jackson, Jonathan; Ali, Ibne Karim M; Chong-Kit, Ann; Gasgas, Jason; Tian, Jinfang; Ralevski, Filip; Boggild, Andrea K

    2015-10-01

    Amoebic keratitis (AK) is a potentially blinding infection, the prompt diagnosis of which is essential for limiting ocular morbidity. We undertook a quality improvement initiative with respect to the molecular detection of acanthamoebae in our laboratory because of an unusual case of discordance. Nine ATCC strains of Acanthamoeba and 40 delinked, biobanked, surplus corneal scraping specimens were analyzed for the presence of acanthamoebae with four separate real-time PCR assays. The assay used by the Free-Living and Intestinal Amebas Laboratory of the CDC was considered the reference standard, and the performance characteristics of each individual assay and pairs of assays were calculated. Outcome measures were sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). Of 49 included specimens, 14 (28.6%) were positive by the gold standard assay, and 35 (71.4%) were negative. The sensitivities of the individual assays ranged from 64.3% to 92.9%, compared to the gold standard, while the specificities ranged from 88.6% to 91.4%. The PPVs and NPVs ranged from 69.2% to 78.6% and from 86.1% to 96.9%, respectively. Combinations of assay pairs led to improved performance, with sensitivities ranging from 92.9% to 100% and specificities ranging from 97.1% to 100%. ATCC and clinical strains of Acanthamoeba that failed to be detected by certain individual assays included Acanthamoeba castellanii, Acanthamoeba culbertsoni, and Acanthamoeba lenticulata. For three clinical specimens, false negativity of the gold standard assay could not be excluded. Molecular diagnostic approaches, especially combinations of highly sensitive and specific assays, offer a reasonably performing, operator-independent, rapid strategy for the detection of acanthamoebae in clinical specimens and are likely to be more practical than either culture or direct microscopic detection.

  20. In the case of transmission of Mycobacterium ulcerans in buruli ulcer disease Acanthamoeba species stand accused.

    PubMed

    Wilson, M D; Boakye, D A; Mosi, L; Asiedu, K

    2011-03-01

    Buruli ulcer disease caused by Mycobacterium ulcerans results in extensive destruction of skin and soft tissue and long-term functional disabilities that ultimately require surgery and rehabilitation. The disease is associated with aquatic and swampy environments with the mycobacterium occurring in biofilms, soil, aquatic insects, fish and wildlife however, the mode of transmission to humans remains an enigma. Current transmission ideas including bites from predatory water bugs and mosquitoes, do not explain satisfactorily the spasmodic disease distribution in human populations. Here we argue that Acanthamoeba species are the natural hosts of M. ulcerans and are mainly responsible for disease transmission because; (i) Acanthamoebae are known natural hosts of several microbial pathogens including M. marinum, M. avium and Legionella pneumophila, (ii) culture of slow-to-grow microbial pathogens hosted in nature by Acanthamoeba spp is enhanced when the media is seeded with the protozoa, (iii) acanthamoebae and M. ulcerans share similar bio-ecological and epidemiological settings, (iv) documented evidence that prior growth of L. pneumophila and M. avium in acanthamoebae influences entry mechanisms, intracellular growth and virulence in human monocytes, (v) Acanthamoeba spp also infect humans and cause diseases via routes of openings including broken skin and sites of trauma similar to M. ulcerans and (vi) M. ulcerans is rather a fastidious intracellular organism as recent analysis of the genome indicate. We argue further that temperature plays a significant role in transmission determining the fate of either the intracellular microbe or the host cells. Also, Acanthamoeba-pathogen association has a long evolutionary history because the same set of bacterial genes and gene products e.g. in L. pneumophila are required for survival in both mammalian and protozoan host cells. We suggest that the involvement of Acanthamoeba in the transmission of M. ulcerans to humans better

  1. Identification of 18S ribosomal DNA genotype of Acanthamoeba from hot spring recreation areas in the central range, Taiwan

    NASA Astrophysics Data System (ADS)

    Hsu, Bing-Mu; Ma, Po-Hua; Liou, Tai-Sheng; Chen, Jung-Sheng; Shih, Feng-Cheng

    2009-04-01

    SummaryAcanthamoeba is a free-living amoebae ubiquitous to aquatic environments. Within the genus a few species are recognized as opportunistic potential human pathogens, which cause granulomatous amoebic encephalitis (GAE) and keratitis. Infections of keratitis are frequently reported through wearing lens while swimming in the non-disinfected aquatic environment. Contaminations in hot tubs, spas and public baths are also possible. As a result, in this study, we identified Acanthamoeba based on the PCR amplification with a genus-specific primer pair and investigated the distribution of Acanthamoeba at five hot spring recreation areas in central range, Taiwan. We gathered data on factors potentially associated with the pathogen's distribution, including various sampling sites, aquatic environment, physical and microbiological water quality parameters. Spring water was collected from 55 sites and Acanthamoeba was detected in 9 (16.4%). The most frequently detected was Acanthamoeba griffini, followed by Acanthamoeba jacobsi. Legionella were detected in 18 (32.7%) of the sites sampled in this study. The species of Legionella identified included Legionella pneumophila serotype 6, serotype 1, and Legionella erythra. Overall, 9.1% of the samples contained both Acanthamoeba and Legionella. The prevalence of Acanthamoeba was contrary to the levels of microbiological indicators recommended by Taiwan CDC, and no significant differences (Mann-Whitney U test, P < 0.05) were observed between the presence/absence of Acanthamoeba and water quality parameters. Results of this survey confirm the existence of Acanthamoeba in Taiwan spring recreation areas. Acanthamoeba, the organism responsible for the majority of Acanthamoeba keratitis and can serve as vehicles for facultative pathogens, should be considered a potential threat for health associated with human activities in spring recreation areas of Taiwan.

  2. Molecular characterization of bacterial endosymbionts of Acanthamoeba isolates from infected corneas of Korean patients.

    PubMed

    Xuan, Ying-Hua; Yu, Hak Sun; Jeong, Hae Jin; Seol, Sung-Yong; Chung, Dong-Il; Kong, Hyun-Hee

    2007-03-01

    The endosymbionts of 4 strains of Acanthamoeba (KA/E9, KA/E21, KA/E22, and KA/E23) isolated from the infected corneas of Korean patients were characterized via orcein stain, transmission electron microscopic examination, and 16S rDNA sequence analysis. Double membrane-bound, rod-shaped endosymbionts were distributed randomly throughout both the trophozoites and cysts of each of Acanthamoeba isolates. The endosymbionts of KA/E9, KA/E22, and KA/E23 were surrounded by electron-translucent areas. No lacunae-like structures were observed in the endosymbionts of KA/E21, the bacterial cell walls of which were studded with host ribosomes. Comparative analyses of the 16S rDNA sequences showed that the endosymbionts of KA/E9, KA/E22 and KA/E23 were closely related to Caedibacter caryophilus, whereas the KA/E21 endosymbiont was assigned to the Cytophaga-Flavobacterium-Bacteroides (CFB) phylum. In the 4 strains of Acanthamoeba, the hosts of the endosymbionts were identified as belonging to the Acanthamoeba castellanii complex, which corresponds to the T4 genotype. Acanthamoeba KA/E21 evidenced characteristics almost identical to those of KA/E6, with the exception of the existence of endosymbionts. The discovery of these endosymbionts from Acanthamoeba may prove essential to future studies focusing on interactions between the endosymbionts and the amoebic hosts. PMID:17374972

  3. Evaluation of Ozone Application in Dental Unit Water Lines Contaminated with Pathogenic Acanthamoeba

    PubMed Central

    HIKAL, Wafaa; ZAKI, Basma; SABRY, Hany

    2015-01-01

    Background: In this study morphological and molecular characterization of Acanthamoeba strains, isolated from dental unit waterlines (DUWLs) were surveyed and the levels of disinfection achievable in vitro by the application of ozone disinfectant to DUWLs were evaluate. Methods: Water samples were collected from air-water syringes, cup fillers and tap water before and at the end of the working day. They were cultured on non-nutrient agar (NNA) plates. Species identification was carried out with a PCR assay based on sequence analysis of the 18S rRNA gene. The cellular response to ozone was tested on Acanthamoeba cyst with different doses at different contact time in vitro twice. Results: Prevalence rates for Acanthamoeba contamination were 100, 100 and 72% for air-water syringes, cup fillers and tap water, respectively. The morphological analysis revealed the presence of A. castellanii, A. griffin, A. hatchitti and A. lenticulata. Phylogenetic analysis of the sequences showed the four strains to be closely related to a sequence type (T3, T4, T5 and T11). Acanthamoeba cells were stained with trypan blue, which revealed killed of Acanthamoeba instantaneously after 10 minutes in ozonized water. There was no growth of Acanthamoeba occurred after ozone treatment in water bottles for 5 minutes with a flow rate of 500 mg/hour. Conclusion : Ozone can play an important role in controlling the problem of contamination of DUWLs as a potent disinfectant. PMID:26622296

  4. Comparative analyses of different genetic markers for the detection of Acanthamoeba spp. isolates.

    PubMed

    Derda, Monika; Wojtkowiak-Giera, Agnieszka; Hadaś, Edward

    2014-09-01

    Acanthamoeba are widespread free-living amoebae which may cause granulomatous amoebic encephalitis (GAE), keratitis, skin ulcerations and disseminated tissue infection. An important diagnostic and prognostic factor for the treatment of infection is a quick and correct diagnosis of amoebae strains. The aim of our study was to develop a rapid method for detection and identification of pathogenic Acanthamoeba spp. strains from diagnostic material collected from water. In this study we analysed five amplification-based genetic markers (Aca 16S, Ac6/210, GP, JDP, Nelson) used for identification of pathogenic Acanthamoeba spp. strains isolated in water sources in Poland, Iceland and Sweden. Our results demonstrated the presence of pathogenic Acanthamoeba strains in tap water. PCR assay appeared to be a more rapid and sensitive method to detect the presence of amoebae than the limited conventional techniques. Based on our observations, we can confirm that the use of four out of five genetic markers (Aca 16S, Ac 6/210, JDP, GP, Nelson) may be helpful in identification of Acanthamoeba spp. strains, but only one Aca 16S primer pair is a highly specific marker that distinguishes between pathogenic strains of Acanthamoeba and other free-living amoeba families.

  5. Fluorescent labeling of Acanthamoeba assessed in situ from corneal sectioned microscopy

    PubMed Central

    Marcos, Susana; Requejo-Isidro, Jose; Merayo-Lloves, Jesus; Acuña, A. Ulises; Hornillos, Valentin; Carrillo, Eugenia; Pérez-Merino, Pablo; del Olmo-Aguado, Susana; del Aguila, Carmen; Amat-Guerri, Francisco; Rivas, Luis

    2012-01-01

    Acanthamoeba keratitis is a serious pathogenic corneal disease, with challenging diagnosis. Standard diagnostic methods include corneal biopsy (involving cell culture) and in vivo reflection corneal microscopy (in which the visualization of the pathogen is challenged by the presence of multiple reflectance corneal structures). We present a new imaging method based on fluorescence sectioned microscopy for visualization of Acanthamoeba. A fluorescent marker (MT-11-BDP), composed by a fluorescent group (BODIPY) inserted in miltefosine (a therapeutic agent against Acanthamoeba), was developed. A custom-developed fluorescent structured illumination sectioned corneal microscope (excitation wavelength: 488 nm; axial/lateral resolution: 2.6 μm/0.4-0.6 μm) was used to image intact enucleated rabbit eyes, injected with a solution of stained Acanthamoeba in the stroma. Fluorescent sectioned microscopic images of intact enucleated rabbit eyes revealed stained Acanthamoeba trophozoites within the stroma, easily identified by the contrasted fluorescent emission, size and shape. Control experiments show that the fluorescent maker is not internalized by corneal cells, making the developed marker specific to the pathogen. Fluorescent sectioned microscopy shows potential for specific diagnosis of Acanthamoeba keratitis. Corneal confocal microscopy, provided with a fluorescent channel, could be largely improved in specificity and sensitivity in combination with specific fluorescent marking. PMID:23082290

  6. Acanthamoeba, fungal, and bacterial keratitis: a comparison of risk factors and clinical features

    PubMed Central

    Mascarenhas, Jeena; Lalitha, Prajna; Prajna, N. Venkatesh; Srinivasan, Muthiah; Das, Manoranjan; D’Silva, Sean S.; Oldenburg, Catherine E.; Borkar, Durga S.; Esterberg, Elizabeth J.; Lietman, Thomas M.; Keenan, Jeremy D.

    2013-01-01

    Purpose To determine risk factors and clinical signs that may differentiate between bacterial, fungal, and acanthamoeba keratitis among patients presenting with presumed infectious keratitis. Design Hospital-based cross-sectional study. Methods We examined the medical records of 115 patients with laboratory-proven bacterial keratitis, 115 patients with laboratory-proven fungal keratitis, and 115 patients with laboratory-proven acanthamoeba keratitis seen at Aravind Eye Hospital, Madurai, India, from 2006–2011. Risk factors and clinical features of the three organisms were compared using multinomial logistic regression. Results Of 95 patients with bacterial keratitis, 103 patients with fungal keratitis, and 93 patients with acanthamoeba keratitis who had medical records available for review, 287 (99%) did not wear contact lenses. Differentiating features were more common for acanthamoeba keratitis than for bacterial or fungal keratitis. Compared to patients with bacterial or fungal keratitis, patients with acanthamoeba keratitis were more likely to be younger and to have a longer duration of symptoms, and to have a ring infiltrate or disease confined to the epithelium. Conclusions Risk factors and clinical examination findings can be useful for differentiating acanthamoeba keratitis from bacterial and fungal keratitis. PMID:24200232

  7. First report of an Acanthamoeba genotype T13 isolate as etiological agent of a keratitis in humans.

    PubMed

    Grün, Anna-Lena; Stemplewitz, Birthe; Scheid, Patrick

    2014-06-01

    Several strains of free-living amoebae (FLA) belonging to the genus Acanthamoeba are able to cause a painful sight-threatening disease of the cornea designated as Acanthamoeba keratitis (AK). In this case report, a 22-year-old woman, wearer of soft contact lenses, was treated after the initial examination, and follow-up laboratory results led to the diagnosis of Acanthamoeba keratitis. The patient recovered under the targeted therapy, demonstrating that the acanthamoebae were the etiological agents of the keratitis in this case. The acanthamoebae belonged morphologically to group II. Genotyping of the causative Acanthamoeba strain based on sequences of the PCR amplimer ASA.S1 amplified from 18S ribosomal DNA by using the genus-specific primers JDP1 and JDP2 followed. The phylogenetic comparison of ASA.S1 confirmed that the isolated Acanthamoeba strain is closely related to genotype T13 supported by pairwise sequence identities of 97.1-98.0% and bootstrap support of 980 replicates with reference sequences of genotype T13. These results regarding the Acanthamoeba keratitis-causing isolate KaBo expands the number of known pathogenic genotypes to 12. To our knowledge, this is the first report of a T13 Acanthamoeba genotype being associated with keratitis in humans. PMID:24802868

  8. [Acanthamoeba isolated from child thymus: Acanthamoeba growth during cocultivation with human and murine eukaryotic cells and induction of cytopathogenic effect on these cells].

    PubMed

    Komogorova, V V; Sharova, N I; Gordeeva, L M; Iarilin, A A

    2003-01-01

    A cell line of the ameba assigned to the genus Acanthamoeba by morphological and cariotypic signs and by the specific features of its life cycle was isolated from the thymus of a child operated on for heart disease. The line received the name CDHT (Cells Derived from Human Thymus). Actively proliferating mammalian cells maintain the multiplication of Acanthamoeba cells in vitro. Using thymocytes as an example, it was shown that death of these cells occurred through the mechanism of apoptosis. The human thymocytes preincubated with the supernatant obtained through the cocultivation of CDHT and thymocytes may also undergo apoptosis. PMID:12886588

  9. Nitrogen Mineralization by Acanthamoeba polyphaga in Grazed Pseudomonas paucimobilis Populations

    PubMed Central

    Sinclair, James L.; McClellan, J. Forbes; Coleman, David C.

    1981-01-01

    Nitrogen mineralization was studied in a simple grazing system in which the protozoan Acanthamoeba polyphaga was grown with the bacterium Pseudomonas paucimobilis (two soil organisms isolated from the shortgrass prairie in northern Colorado). In different experiments, either carbon or nitrogen was adjusted to be in limiting amounts. When carbon was limiting, grazers were almost entirely responsible for nitrogen mineralization, with bacteria themselves contributing little. When nitrogen was limiting, nitrogen mineralization by grazers permitted continued growth by the grazed bacteria and a greater bacterial biomass production. The increased growth of the grazed bacteria did not result in an increased total amount of carbon used, but the grazed bacteria used carbon more efficiently than the ungrazed bacteria. PMID:16345864

  10. Arcobacter butzleri survives within trophozoite of Acanthamoeba castellanii.

    PubMed

    Villanueva, María P; Medina, Gustavo; Fernández, Heriberto

    2016-01-01

    The survival of three Arcobacter butzleri strains inside Acanthamoeba castellanii was assessed using axenic cultures of A. castellanii that were inoculated with the tested strains and incubated at 26°C under aerobic conditions for 240h. The behavior of bacteria in contact with amoebae was monitored using phase contrast microscopy. The bacterial survival rate within amoebae was assessed through counting colony forming units, using the gentamicin protection assay. All A. butzleri strains were able to survive during 240h within the amoebae, thus suggesting that (i) A. butzleri resists the amoebic digestion processes at least for the analyzed time; (ii) that A. castellanii could serve as an environmental reservoir for this bacterium, probably acting as a transmission vehicle for A. butzleri. PMID:26972277

  11. Cryptococcus neoformans: pseudohyphal forms surviving culture with Acanthamoeba polyphaga.

    PubMed Central

    Neilson, J B; Ivey, M H; Bulmer, G S

    1978-01-01

    During experiments on the gastrointestinal tract as a possible portal of entry for Cryptococcus neoformans, we occasionally observed the free-living amoeba, Acanthamoeba polyphaga, growing in the presence of C. neoformans cultured from mouse feces. Examination of the amoebic trophozoites revealed that they were engorged with yeast cells. Over a period of 2 to 3 weeks of incubation, the amoebae apparently killed most of the yeast cells. Some of the surviving C. neoformans cells formed atypical colonies which contained pseudohyphae. Seven other strains have since been cultured with this amoeba. Pseudohyphal forms were found among the surviving colonies in all strains tested. Virulence studies were performed on one randomly selected pseudohyphal isolate from each of the eight strains of C. neoformans. Pseudohyphal isolates from seven of the eight strains failed to kill mice 30 days after intracranial inoculation. The potential role of soil amoebae in the control of C. neoformans in nature is discussed. Images PMID:352931

  12. Acanthamoeba and bacteria produce antimicrobials to target their counterpart

    PubMed Central

    2014-01-01

    Background In the microbial ecosystem, microbes compete for space and nutrients. Consequently, some have developed the ability to kill or inhibit the growth of other competing microbes by producing antimicrobial substances. As the ‘producer’ species are generally immune to these substances, their compounds act on the competing microbial species and give the producer more space and access to nutrients for growth. Many currently used antibiotics were developed by exploiting this potential of certain microbes. Findings Here, the free-living amoeba, Acanthamoeba castellanii, was investigated for its antibacterial activity against representative Gram positive and Gram negative bacteria, while bacterial isolates were tested for their anti-amoebic properties. Conditioned medium from A. castellanii showed remarkable bactericidal properties against methicillin-resistant Staphylococcus aureus (MRSA) exhibiting almost 100% kill rate, but had limited effect against Acinetobacter sp., Pseudomonas aeruginosa and vancomycin-resistant Enterococcus faecalis (VRE). Similarly, the conditioned medium of E. coli K1 and Enterobacter sp., exhibited potent anti-Acanthamoebic effects in a concentration-dependent manner. Conditioned media of Acanthamoeba, E. coli K1 and Enterobacter sp. showed no cytotoxicity in vitro when tested against human brain microvascular endothelial cells. Active molecule/s in aforementioned amoebic and two bacterial conditioned media were 5 – 10 kDa, and <5 kDa respectively. Conclusions A. castellanii conditioned medium showed potent bactericidal properties against MRSA. The active molecule(s) are heat- and pronase-resistant, and in the 5 to 10 kDa molecular mass range. Contrary to this, E. coli K1 and Enterobacter sp., conditioned medium showed anti-amoebic effects that are <5 kDa in molecular mass, suggestive of active metabolites. PMID:24479709

  13. A unique astigmatic nodal property in misaligned Ritchey-Chrétien telescopes with misalignment coma removed.

    PubMed

    Schmid, Tobias; Thompson, Kevin P; Rolland, Jannick P

    2010-03-01

    We present the aberration field response of Ritchey-Chrétien telescopes, with the aperture stop on the primary mirror, to secondary mirror misalignments. More specifically, we derive a general condition for the geometry of the binodal astigmatic aberration field for a telescope that has been aligned to remove field-constant coma. It has been observed that when the coma caused by secondary mirror misalignments is removed the astigmatic field is typically not symmetric around the periphery, but, significantly, it is always effectively zero on-axis. This observation is a manifestation of binodal astigmatism where one of the astigmatic nodes remains near the field center. Here, we show how the condition to remove field-constant coma simultaneously creates a constraint whereby one of the astigmatic nodes must remain effectively on-axis. This result points to why the alignment of a large telescope based on axial imagery is insufficient and demonstrates exactly the geometry of the remaining misalignment aberration field, which dominates the performance of the telescope, providing insights into more complete alignment approaches.

  14. Pathogenic Strains of Acanthamoeba Are Recognized by TLR4 and Initiated Inflammatory Responses in the Cornea

    PubMed Central

    Alizadeh, Hassan; Tripathi, Trivendra; Abdi, Mahshid; Smith, Ashley Dawn

    2014-01-01

    Free-living amoebae of the Acanthamoeba species are the causative agent of Acanthamoeba keratitis (AK), a sight-threatening corneal infection that causes severe pain and a characteristic ring-shaped corneal infiltrate. Innate immune responses play an important role in resistance against AK. The aim of this study is to determine if Toll-like receptors (TLRs) on corneal epithelial cells are activated by Acanthamoeba, leading to initiation of inflammatory responses in the cornea. Human corneal epithelial (HCE) cells constitutively expressed TLR1, TLR2, TLR3, TLR4, and TLR9 mRNA, and A. castellanii upregulated TLR4 transcription. Expression of TLR1, TLR2, TLR3, and TLR9 was unchanged when HCE cells were exposed to A. castellanii. IL-8 mRNA expression was upregulated in HCE cells exposed to A. castellanii. A. castellanii and lipopolysaccharide (LPS) induced significant IL-8 production by HCE cells as measured by ELISA. The percentage of total cells positive for TLR4 was higher in A. castellanii stimulated HCE cells compared to unstimulated HCE cells. A. castellanii induced upregulation of IL-8 in TLR4 expressing human embryonic kidney (HEK)-293 cells, but not TLR3 expressing HEK-293 cells. TLR4 neutralizing antibody inhibited A. castellanii-induced IL-8 by HCE and HEK-293 cells. Clinical strains but not soil strains of Acanthamoeba activated TLR4 expression in Chinese hamster corneas in vivo and in vitro. Clinical isolates but not soil isolates of Acanthamoeba induced significant (P< 0.05) CXCL2 production in Chinese hamster corneas 3 and 7 days after infection, which coincided with increased inflammatory cells in the corneas. Results suggest that pathogenic species of Acanthamoeba activate TLR4 and induce production of CXCL2 in the Chinese hamster model of AK. TLR4 may be a potential target in the development of novel treatment strategies in Acanthamoeba and other microbial infections that activate TLR4 in corneal cells. PMID:24633052

  15. [Use of the presence of cellulose in cellular wall of Acanthamoeba cysts for diagnostic purposes].

    PubMed

    Derda, Monika; Hadaś, Edward

    2009-01-01

    Species identification within the genus Acanthamoeba is based predominantly on morphological and biochemical features. It is labor-intensive and requires cloning and axenization. We described a novel immunocytochemical method for the identification of Acanthamoeba spp. based on selective binding of Clostridium cellulovorans cellulase to protozoan cyst wall cellulose. Free-living amoebae isolated from different water sources by filtration and subsequent cultivation on non-nutrient agar were assigned to genera Acanthamoeba, Naegleria or Hartmannella using morphological taxonomic criteria. Tissues samples from experimentally infected mice were fixed in formalin and for sectioning embedded in paraffin or snap frozen. The Cellulose-Binding Domain of C. cellulovorans cellulase (CBD) obtained as a recombinant protein, were coupled to the fluorescent dye using Alexa Fluor350, 488, 568 - Protein Labelling Kit or labelled with the biotin using EZ-Link Sulfo-NHS-Biotin. All coupling procedures were performed according to the methods provided by manufacturers. For staining with CBD conjugate, slides containing cysts collected from the agar plates or tissue sections were immersed with PBS and incubated with CBD for 30 min at room temperature, washed 3 times with PBS. For staining with CBD-biotin slides containing cysts were incubated with biotinylated CBD for 30 min at room temperature. Subsequent washings in changes of PBS were followed by the incubation with Strept ABComplex/HRP, for 30 min at room temperature, than 3,3 diaminobenzidine tetrahydrochloride was added for 15 min. Slides were rinsed with water, dried and examined in the light microscope. We showed that cellulose could be easily detected by immunofluorescence using conjugated CBD in the inner cyst wall of Acanthamoeba spp. The reference strains of Acanthamoeba spp. and all Acanthamoeba strains isolated from water and from tissues of infected animals gave positive reaction. CBD prepared as a biotynylated protein

  16. Visual outcomes of topography-guided excimer laser surgery for treatment of patients with irregular astigmatism.

    PubMed

    Ghoreishi, Mohammad; Naderi Beni, Afsaneh; Naderi Beni, Zahra

    2014-01-01

    The aim of this study was to evaluate the efficacy, safety, and predictability of topography-guided treatments to enhance refractive status following other corneal surgical procedures. In a prospective case series study, 28 consecutive eyes of 26 patients with irregular astigmatism after radial keratotomy, corneal transplant, small hyperopic and myopic excimer laser optical zones, and corneal scars were operated. Laser-assisted in situ keratomileusis (LASIK) (n = 8) and photorefractive keratectomy (PRK) (n = 20) were performed using the ALLEGRETTO WAVE excimer laser and topography-guided customized ablation treatment software. Preoperative and postoperative uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), manifest and cycloplegic refraction, and corneal topography with asphericity were analyzed in 12 months follow-up. Uncorrected visual acuity (UCVA) changed from 0.2 ± 0.2 or (20/100 ± 20/100) to 0.51 ± 0.31 or (20/40 ± 20/60) in the LASIK group (P = 0.01) and from 0.34 ± 0.16 or (20/60 ± 20/120) to 0.5 ± 0.23 or (20/40 ± 20/80) in the PRK group (P = 0.01). Refractive cylinder decreased from -3.2 ± 0.84 diopters (D) to -2.06 ± 0.42 D in the LASIK group (P = 0.07) and from -2.25 ± 0.39 D to -1.5 ± 0.23 D in the PRK group (P = 0.008). Best corrected visual acuity did not change significantly in either group. Topography-guided treatment is effective in correcting the irregular astigmatism after refractive surgery. Topography-guided PRK can significantly reduce irregular astigmatism and increase the UCVA and BCVA.

  17. Astigmatic multifocus microscopy enables deep 3D super-resolved imaging

    PubMed Central

    Oudjedi, Laura; Fiche, Jean-Bernard; Abrahamsson, Sara; Mazenq, Laurent; Lecestre, Aurélie; Calmon, Pierre-François; Cerf, Aline; Nöllmann, Marcelo

    2016-01-01

    We have developed a 3D super-resolution microscopy method that enables deep imaging in cells. This technique relies on the effective combination of multifocus microscopy and astigmatic 3D single-molecule localization microscopy. We describe the optical system and the fabrication process of its key element, the multifocus grating. Then, two strategies for localizing emitters with our imaging method are presented and compared with a previously described deep 3D localization algorithm. Finally, we demonstrate the performance of the method by imaging the nuclear envelope of eukaryotic cells reaching a depth of field of ~4µm. PMID:27375935

  18. Astigmatic multifocus microscopy enables deep 3D super-resolved imaging.

    PubMed

    Oudjedi, Laura; Fiche, Jean-Bernard; Abrahamsson, Sara; Mazenq, Laurent; Lecestre, Aurélie; Calmon, Pierre-François; Cerf, Aline; Nöllmann, Marcelo

    2016-06-01

    We have developed a 3D super-resolution microscopy method that enables deep imaging in cells. This technique relies on the effective combination of multifocus microscopy and astigmatic 3D single-molecule localization microscopy. We describe the optical system and the fabrication process of its key element, the multifocus grating. Then, two strategies for localizing emitters with our imaging method are presented and compared with a previously described deep 3D localization algorithm. Finally, we demonstrate the performance of the method by imaging the nuclear envelope of eukaryotic cells reaching a depth of field of ~4µm.

  19. The construction of sutureless cataract incision and the management of corneal astigmatism.

    PubMed

    Hall, G W; Krischer, C; Mobasher, B; Rajan, S D

    1993-02-01

    Extrapolating information from equations that govern fluid flow, a theoretical formula is developed for a sutureless cataract incision. This theoretical formula defines the resistance of aqueous outflow as a function of three variables: length of cataract incision, the length of the scleral tunnel, the tortuosity of the outflow channel, and one constant friction factor. The nonlinear relationship of corneal incisions to length, depth, and distance from the visual axis is also examined with respect to their effect on central corneal curvature and control of astigmatism. Finite element analysis of differential equations is discussed as the most plausible technique for predicting these incisional effects.

  20. Long-term outcomes of wedge resection at the limbus for high irregular corneal astigmatism after repaired corneal laceration

    PubMed Central

    Du, Jun; Zheng, Guang-Ying; Wen, Cheng-Lin; Zhang, Xiao-Fang; Zhu, Yu

    2016-01-01

    AIM To evaluate the clinical value of wedge resection at corneal limbus in patients with traumatic corneal scarring and high irregular astigmatism. METHODS Patients with traumatic corneal astigmatism received wedge resection at least 6mo after suture removal from corneal wound. The uncorrected distance visual acuities (UCVA) and best corrected distance visual acuities (BCVA), pre- and post-operation astigmatism, spherical equivalent (SE), safety and complications were evaluated. RESULTS Ten eyes (10 patients) were enrolled in this study. Mean follow-up time after wedge resection was 37.8±15.4mo (range, 20-61mo). The mean UCVA improved from +1.07±0.55 logMAR to +0.43±0.22 logMAR (P=0.000) and the mean BCVA from +0.50±0.30 logMAR to +0.15±0.17 logMAR (P=0.000). The mean astigmatism power measured by retinoscopy was -2.03±2.27 D postoperatively and -2.83±4.52 D preoperatively (P=0.310). The mean SE was -0.74±1.61 D postoperatively and -0.64±1.89 D preoperatively (P=0.601). Two cases developed mild pannus near the sutures. No corneal perforation, infectious keratitis or wound gape occurred. CONCLUSION Corneal-scleral limbal wedge resection with compression suture is a safe, effective treatment for poor patients with high irregular corneal astigmatism after corneal-scleral penetrating injury. Retinoscopy can prove particularly useful for high irregular corneal astigmatism when other measurements are not amenable. PMID:27366685

  1. A multisystemic Acanthamoeba infection in a dog in Tenerife, Canary Islands, Spain.

    PubMed

    Valladares, María; Reyes-Batlle, María; Mora-Peces, Inmaculada; Martín-Navarro, Carmen M; López-Arencibia, Atteneri; Dorta-Gorrín, Alexis; Comyn-Afonso, Estefanía; Martínez-Carretero, Enrique; Maciver, Sutherland K; Piñero, José E; Valladares, Basilio; Lorenzo-Morales, Jacob

    2014-10-15

    A 22-month-old male Spanish water dog was hospitalized after its physical examination revealed fever and movement difficulty. After 24h, the dog was found to have a high fever (39.5 °C) and was treated empirically with doxycycline/ciprofloxacin. At 48 h, after submission the fever rose to 41 °C and the animal presented with a stiff neck and dehydration. Peripheral blood and cerebrospinal fluid (CSF) were sampled and trophozoites with an Acanthamoeba-like morphology were observed in the CSF. PCR specific for Acanthamoeba, Naegleria fowleri and Balamuthia mandrillaris were performed and the CSF sample found positive for Acanthamoeba. Lungs, kidney, liver and spleen samples were collected post mortem. All collected organ samples were positive for Acanthamoeba by PCR, thus confirming a multisystemic infection. Water samples taken at a suspected site of infection yielded an almost identical PCR fragment to those of the clinical samples, indicating that this was probably where the infection originated. This is the first report of a fatal case of Acanthamoeba disseminated infection in a dog in Spain. PMID:25193180

  2. Acanthamoeba genotypes T3 and T4 as causative agents of amoebic keratitis in Mexico.

    PubMed

    Omaña-Molina, Maritza; Vanzzini-Zago, Virginia; Hernandez-Martinez, Dolores; Gonzalez-Robles, Arturo; Salazar-Villatoro, Lizbeth; Ramirez-Flores, Elizabeth; Oregon-Miranda, Eric; Lorenzo-Morales, Jacob; Martinez-Palomo, Adolfo

    2016-02-01

    Free-living amoebae (FLA) are widely distributed worldwide. Some genera included in this group act as opportunistic pathogens causing fatal encephalitis and Acanthamoeba keratitis (AK), a sight-threatening infection of the cornea associated with the use of soft contact lenses that could even end in blindness if an early diagnosis and treatment are not achieved. Furthermore, the numbers of AK cases keep rising worldwide mainly due to an increase of contact lens wearers and lack of hygiene in the maintenance of lenses and their cases. In Mexico, no cases of AK have been described so far although the isolation of other pathogenic FLA such as Naegleria fowleri and Balamuthia mandrillaris from both clinical and environmental sources has been reported. The present study reports two cases of Acanthamoeba keratitis diagnosed in two patients admitted to the Hospital "Luis Sánchez Bulnes" for Blindness Prevention in Mexico City, Mexico. Corneal scrapes and contact lenses were checked for the presence of Acanthamoeba strains in both patients. Strains were axenized after initial isolation to classify at the genotype level. After sequencing the diagnostic fragment 3 (DF3) region located on the 18S ribosomal DNA (rDNA) gene of Acanthamoeba, genotype T3 and genotype T4 were identified in clinical case 1 and 2, respectively. To our knowledge, these are the first reported cases of AK in Mexico in the literature and the first description of Acanthamoeba genotypes T3 and T4 as causative agents of amoebic infection. PMID:26581373

  3. Isolation and Genotyping of Acanthamoeba spp. as Neglected Parasites in North of Iran

    PubMed Central

    Shokri, Azar; Sarvi, Shahabeddin; Daryani, Ahmad; Sharif, Mehdi

    2016-01-01

    Acanthamoeba, a free-living amoeba, is widely distributed in the environment, water sources, soil, dust, and air. It can cause keratitis in contact lens wearers with poor hygiene and also fatal granulomatous amebic encephalitis (GAE) in immunocompromised hosts. The aim of this study was to gain some insights into the distribution and genotypes of the potentially pathogenic species of Acanthamoeba present in water sources in north of Iran. Total 43 Acanthamoeba species were isolated from 77 water samples taken from different water sources within the Mazandaran province in Northern Iran (Sari city and suburbs). Isolates were identified based on cyst and trophozoite morphological characteristics as well genetics. PCR fragments corresponding to the small-subunit 18S rRNA gene were sequenced for 20 of 43 positive isolates. The results revealed that 83.3% of sequenced isolates belonged to the T4 genotype and the rest belonged to the T2 genotype. Our results indicated that Acanthamoeba is widely distributed in Sari city. As the incidence in Iran of amoebic keratitis has increased in recent years, the exact estimation of the prevalence of this amoeba and its predominant genotype may play a crucial role in prevention of the disease. Sari city has several rivers, seashores, and natural recreational amenities, which attract visitors during the year. This is the first report of Acanthamoeba genotypes from water sources in Sari city, Mazandaran province of Iran, and the results suggest that more attention is needed to protect the visiting population and immunocompromised individuals. PMID:27658596

  4. Detection and quantification of human adenovirus genomes in Acanthamoeba isolated from swimming pools.

    PubMed

    Staggemeier, Rodrigo; Arantes, Thalita; Caumo, Karin S; Rott, Marilise B; Spilki, Fernando R

    2016-01-01

    Acanthamoeba is the most common free-living environmental amoeba, it may serve as an important vehicle for various microorganisms living in the same environment, such as viruses, being pathogenic to humans. This study aimed to detect and quantify human adenoviruses (HAdV) in Acanthamoebas isolated from water samples collected from swimming pools in the city of Porto Alegre, Southern Brazil. Free-living amoebae of the genus Acanthamoeba were isolated from water samples, and isolates (n=16) were used to investigate the occurrence of HAdVs. HAdV detection was performed by quantitative real-time polymerase chain reaction (qPCR). HAdVs were detected in 62.5% (10/16) of Acanthamoeba isolates, ranging from 3.24x103 to 5.14x105 DNA copies per milliliter of isolate. HAdV viral loads found in this study are not negligible, especially because HAdV infections are associated with several human diseases, including gastroenteritis, respiratory distress, and ocular diseases. These findings reinforce the concept that Acanthamoeba may act as a reservoir and promote HAdV transmission through water. PMID:27142544

  5. Isolation and Genotyping of Acanthamoeba spp. as Neglected Parasites in North of Iran.

    PubMed

    Shokri, Azar; Sarvi, Shahabeddin; Daryani, Ahmad; Sharif, Mehdi

    2016-08-01

    Acanthamoeba, a free-living amoeba, is widely distributed in the environment, water sources, soil, dust, and air. It can cause keratitis in contact lens wearers with poor hygiene and also fatal granulomatous amebic encephalitis (GAE) in immunocompromised hosts. The aim of this study was to gain some insights into the distribution and genotypes of the potentially pathogenic species of Acanthamoeba present in water sources in north of Iran. Total 43 Acanthamoeba species were isolated from 77 water samples taken from different water sources within the Mazandaran province in Northern Iran (Sari city and suburbs). Isolates were identified based on cyst and trophozoite morphological characteristics as well genetics. PCR fragments corresponding to the small-subunit 18S rRNA gene were sequenced for 20 of 43 positive isolates. The results revealed that 83.3% of sequenced isolates belonged to the T4 genotype and the rest belonged to the T2 genotype. Our results indicated that Acanthamoeba is widely distributed in Sari city. As the incidence in Iran of amoebic keratitis has increased in recent years, the exact estimation of the prevalence of this amoeba and its predominant genotype may play a crucial role in prevention of the disease. Sari city has several rivers, seashores, and natural recreational amenities, which attract visitors during the year. This is the first report of Acanthamoeba genotypes from water sources in Sari city, Mazandaran province of Iran, and the results suggest that more attention is needed to protect the visiting population and immunocompromised individuals. PMID:27658596

  6. Viability and morphological changes of Acanthamoeba spp. cysts after treatment with Effective microorganisms (EM).

    PubMed

    Sampaotong, Tanitta; Lek-Uthai, Usa; Roongruangchai, Jantima; Roongruangchai, Kosol

    2016-06-01

    Acanthamoeba is a free-living opportunistic protozoan parasite that is found in diverse environments. It can cause keratitis, mostly related to inappropriate use of contact lenses, as well as life threatening diseases including encephalitis, disseminated sinusitis, and skin ulcers. This study investigated morphological changes and fine structures of the cyst form of Acanthamoeba spp. after treatment with effective microorganisms (EM™) using light and scanning electron microscopies. Acanthamoeba cysts treated with 1:2, 1:4, 1:6, and undiluted EM™ showed higher percentages of non-viable cysts than those treated with 1:8, 1:10, 1:100, 1:200, and 1:400 EM™ and at 5 days post-treatment developed from cystic stage to trophozoite stage. Acanthamoeba cysts treated at concentrations of 1:2, 1:4, 1:6, and undiluted EM™ exhibited cytoplasmic clumping and shrinkage of amoeba cells away from cyst walls. The effective EM™ concentration lethal to Acanthamoeba spp. cyst could provide information to monitor the environmental control system. PMID:27413306

  7. Chloroquine Has a Cytotoxic Effect on Acanthamoeba Encystation through Modulation of Autophagy

    PubMed Central

    Jha, Bijay Kumar; Jung, Hui-Jung; Seo, Incheol; Kim, Hyun Ah; Suh, Seong-Il; Suh, Min-Ho

    2014-01-01

    Encystation of Acanthamoeba castellanii is associated with resistance to chemotherapeutic agents. Blocking the encystation process could potentiate the efficacy of chemotherapeutic agents and biocides. During encystation, autophagy is highly stimulated and required for proper encystation of Acanthamoeba. In this study, the cytotoxic effect of chloroquine, a well-known autophagy-inhibitory drug, was tested in A. castellanii. Chloroquine was able to selectively reduce cell survival during the encystation of A. castellanii. However, A. castellanii trophozoites and mature cysts were resistant to chloroquine. Chloroquine treatment led to an increase in the number and size of lysosomes in encysting cells. Moreover, chloroquine inhibited the degradation of long-lived proteins in the encysting cells. Decreased autophagic flux, indicated by an increased number of lysosomes and decreased degradation of long-lived proteins, may be the mechanism by which cell death is induced by chloroquine in encysting Acanthamoeba. These results suggest a potential novel therapeutic application of chloroquine as an anti-Acanthamoeba drug. Our findings also suggest that targeting autophagy could be a therapeutic strategy against Acanthamoeba infection. PMID:25114131

  8. Failure of chemotherapy in the first reported cases of Acanthamoeba keratitis in Pakistan.

    PubMed

    Siddiqui, Ruqaiyyah; Chaudhry, Tanveer; Lakhundi, Sahreena; Ahmad, Khabir; Khan, Naveed Ahmed

    2014-01-01

    Acanthamoeba keratitis is a painful and progressive infection of the cornea that can result in loss of vision. Here, for the first time in Pakistan, we report two cases of Acanthamoeba keratitis. The first patient was a 37-year-old female who presented with severe itching, redness, pain, along with loss of vision. The patient was a regular soft contact lens wearer. The second patient was a 25-year-old female who had been using soft contact lenses for the past two years. She presented with a burning sensation and extreme pain, along with loss of vision. Both patients were treated for a possible microbial keratitis with topical moxifloxacin hydrochloride drops, vancomycin drops, propamidine isethionate ointment, amphotericin B drops, and amikacin drops. However, the response was inadequate and both patients were referred for corneal transplant. Acanthamoeba castellanii was isolated by placing contact lenses and contact lens cases on non-nutrient agar plates containing a lawn of non-invasive Escherichia coli K-12 HB101 bacteria. The polymerase chain reaction (PCR) using genus-specific probes confirmed the identity of Acanthamoeba spp., whereas the morphological characteristics of trophozoites and cysts were suggestive of A. castellanii in both cases. With growing use of contact lenses for vision correction/cosmetic use coupled with sub-standard lens care in this region and the possibility of non-contact lens-associated Acanthamoeba keratitis, a need for increased awareness of this sight-threatening infection is discussed further. PMID:24548160

  9. Isolation and genotyping of acanthamoeba strains from soil sources from Jamaica, West Indies.

    PubMed

    Todd, Cheridah D; Reyes-Batlle, María; Martín-Navarro, Carmen Ma; Dorta-Gorrín, Alexis; López-Arencibia, Atteneri; Martínez-Carretero, Enrique; Piñero, José E; Valladares, Basilio; Lindo, John F; Lorenzo-Morales, Jacob

    2015-01-01

    Acanthamoeba spp. are opportunistic pathogens that are ubiquitous in nature. Many species of this genus are responsible for a fatal encephalitis and keratitis in humans and other animals. Seventy-two soil samples were collected from the parishes across Jamaica and assessed for the presence of Acanthamoeba spp. Cultivation was carried out on non-nutrient agar plates seeded with heat killed Escherichia coli. PCR and sequencing of the DF3 region were carried out in order to genotype the isolated strains of Acanthamoeba. Thermotolerance and osmotolerance assays were utilized to investigate the pathogenic potential of the Acanthamoeba isolates. Acanthamoeba spp. was isolated from 63.9% of soil samples. Sequencing of the DF3 region of the 18S rDNA resulted in the identification of genotypes T4, T5, and T11. T4 genotype was most frequently isolated. Most isolates were thermotolerant or both thermotolerant and osmotolerant, indicating that they may present the potential to cause disease in humans and other animals.

  10. Pathogenic and opportunistic free-living amoebae: Acanthamoeba spp., Balamuthia mandrillaris, Naegleria fowleri, and Sappinia diploidea.

    PubMed

    Visvesvara, Govinda S; Moura, Hercules; Schuster, Frederick L

    2007-06-01

    Among the many genera of free-living amoebae that exist in nature, members of only four genera have an association with human disease: Acanthamoeba spp., Balamuthia mandrillaris, Naegleria fowleri and Sappinia diploidea. Acanthamoeba spp. and B. mandrillaris are opportunistic pathogens causing infections of the central nervous system, lungs, sinuses and skin, mostly in immunocompromised humans. Balamuthia is also associated with disease in immunocompetent children, and Acanthamoeba spp. cause a sight-threatening infection, Acanthamoeba keratitis, mostly in contact-lens wearers. Of more than 30 species of Naegleria, only one species, N. fowleri, causes an acute and fulminating meningoencephalitis in immunocompetent children and young adults. In addition to human infections, Acanthamoeba, Balamuthia and Naegleria can cause central nervous system infections in animals. Because only one human case of encephalitis caused by Sappinia diploidea is known, generalizations about the organism as an agent of disease are premature. In this review we summarize what is known of these free-living amoebae, focusing on their biology, ecology, types of disease and diagnostic methods. We also discuss the clinical profiles, mechanisms of pathogenesis, pathophysiology, immunology, antimicrobial sensitivity and molecular characteristics of these amoebae.

  11. Failure of chemotherapy in the first reported cases of Acanthamoeba keratitis in Pakistan

    PubMed Central

    Siddiqui, Ruqaiyyah; Chaudhry, Tanveer; Lakhundi, Sahreena; Ahmad, Khabir; Khan, Naveed Ahmed

    2014-01-01

    Acanthamoeba keratitis is a painful and progressive infection of the cornea that can result in loss of vision. Here, for the first time in Pakistan, we report two cases of Acanthamoeba keratitis. The first patient was a 37-year-old female who presented with severe itching, redness, pain, along with loss of vision. The patient was a regular soft contact lens wearer. The second patient was a 25-year-old female who had been using soft contact lenses for the past two years. She presented with a burning sensation and extreme pain, along with loss of vision. Both patients were treated for a possible microbial keratitis with topical moxifloxacin hydrochloride drops, vancomycin drops, propamidine isethionate ointment, amphotericin B drops, and amikacin drops. However, the response was inadequate and both patients were referred for corneal transplant. Acanthamoeba castellanii was isolated by placing contact lenses and contact lens cases on non-nutrient agar plates containing a lawn of non-invasive Escherichia coli K-12 HB101 bacteria. The polymerase chain reaction (PCR) using genus-specific probes confirmed the identity of Acanthamoeba spp., whereas the morphological characteristics of trophozoites and cysts were suggestive of A. castellanii in both cases. With growing use of contact lenses for vision correction/cosmetic use coupled with sub-standard lens care in this region and the possibility of non-contact lens-associated Acanthamoeba keratitis, a need for increased awareness of this sight-threatening infection is discussed further. PMID:24548160

  12. Isolation and Genotyping of Acanthamoeba Strains from Environmental Sources in Ahvaz City, Khuzestan Province, Southern Iran

    PubMed Central

    Rahdar, M; Niyyati, M; Salehi, M; Feghhi, M; Makvandi, M; Pourmehdi, M; Farnia, S

    2012-01-01

    Background Acanthamoeba spp. are free-living amoebae commonly found in the environmental sources such as water, soil, and air. This ubiquitous amoeba is the causative agent of amoebic keratitis (AK). The objective of the present study was to investigate the presence of Acanthamoeba spp. in water and soil sources in Ahvaz City, Khuzestan Province, southern Iran. Methods In general, 110 samples of water and soil were taken from different localities of Ahvaz including agricultural canals, rivers, and swimming pools. Filtration and cultivation were carried out on non-nutrient agar medium (NNA). Axenic cultivation was performed for all of positive isolates. PCR analysis was conducted on positive samples. Sequencing was done for 15 PCR products. Genotypes were identified by Blast search and homology analysis. Results Acanthamoeba spp. was found in 43 (71.6%) of samples of water and 13 (26%) soil samples. Genotyping of 15 samples proved that Acanthamoeba belonged to T4 (86.6%), T2 (6.6%), and T5 (6.6%) genotypes. Conclusion TYI-S-33 medium could be better than PYG medium for Acanthamoeba axenic culture. PMID:23323088

  13. Chloroquine has a cytotoxic effect on Acanthamoeba encystation through modulation of autophagy.

    PubMed

    Jha, Bijay Kumar; Jung, Hui-Jung; Seo, Incheol; Kim, Hyun Ah; Suh, Seong-Il; Suh, Min-Ho; Baek, Won-Ki

    2014-10-01

    Encystation of Acanthamoeba castellanii is associated with resistance to chemotherapeutic agents. Blocking the encystation process could potentiate the efficacy of chemotherapeutic agents and biocides. During encystation, autophagy is highly stimulated and required for proper encystation of Acanthamoeba. In this study, the cytotoxic effect of chloroquine, a well-known autophagy-inhibitory drug, was tested in A. castellanii. Chloroquine was able to selectively reduce cell survival during the encystation of A. castellanii. However, A. castellanii trophozoites and mature cysts were resistant to chloroquine. Chloroquine treatment led to an increase in the number and size of lysosomes in encysting cells. Moreover, chloroquine inhibited the degradation of long-lived proteins in the encysting cells. Decreased autophagic flux, indicated by an increased number of lysosomes and decreased degradation of long-lived proteins, may be the mechanism by which cell death is induced by chloroquine in encysting Acanthamoeba. These results suggest a potential novel therapeutic application of chloroquine as an anti-Acanthamoeba drug. Our findings also suggest that targeting autophagy could be a therapeutic strategy against Acanthamoeba infection. PMID:25114131

  14. Optimization of nonimaging focusing heliostat in dynamic correction of astigmatism for a wide range of incident angles.

    PubMed

    Chong, Kok-Keong

    2010-05-15

    To overcome astigmatism has always been a great challenge in designing a heliostat capable of focusing the sunlight on a small receiver throughout the year. In this Letter, a nonimaging focusing heliostat with a dynamic adjustment of facet mirrors in a group manner has been analyzed for optimizing the astigmatic correction in a wide range of incident angles. This what is to the author's knowledge a new heliostat is not only designed to serve the purpose of concentrating sunlight to several hundreds of suns, but also to significantly reduce the variation of the solar flux distribution with the incident angle.

  15. Refractive lenticule extraction (ReLEx) through a small incision (SMILE) for correction of myopia and myopic astigmatism: current perspectives

    PubMed Central

    Ağca, Alper; Demirok, Ahmet; Yıldırım, Yusuf; Demircan, Ali; Yaşa, Dilek; Yeşilkaya, Ceren; Perente, İrfan; Taşkapılı, Muhittin

    2016-01-01

    Small-incision lenticule extraction (SMILE) is an alternative to laser-assisted in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK) for the correction of myopia and myopic astigmatism. SMILE can be performed for the treatment of myopia ≤−12 D and astigmatism ≤5 D. The technology is currently only available in the VisuMax femtosecond laser platform. It offers several advantages over LASIK and PRK; however, hyperopia treatment, topography-guided treatment, and cyclotorsion control are not available in the current platform. The working principles, potential advantages, and disadvantages are discussed in this review. PMID:27757010

  16. Apparatus for and method of correcting for astigmatism in a light beam reflected off of a light reflecting surface

    DOEpatents

    Sawicki, R.H.; Sweatt, W.

    1985-11-21

    A technique for adjustably correcting for astigmatism in a light beam is disclosed herein. This technique defines a flat, rectangular light reflecting surface having opposite reinforced side edges and which is resiliently bendable, to a limited extent, into different concave and/or convex cylindrical curvatures about a particular axis and provides for adjustably bending the light reflecting surface into one of different curvatures depending upon the astigmatism to be corrected and for fixedly maintaining the curvature selected. In the embodiment disclosed, the light reflecting surface is adjustably bendable into the selected cylindrical curvature by application of a particular bending moment to the reinforced side edges of the light reflecting surface.

  17. Quick survey for detection, identification and characterization of Acanthamoeba genotypes from some selected soil and water samples across Pakistan.

    PubMed

    Tanveer, Tania; Hameed, Abdul; Gul, Asma; Matin, Abdul

    2015-01-01

    Acanthamoeba is an opportunistic protozoan pathogen which is widely distributed in nature and plays a pivotal role in ecosystem. Acanthamoeba species may cause blinding keratitis and fatal granulomatous encephalitis involving central nervous system. In this study, we investigated the presence of Acanthamoeba in soil and water resources of Pakistan. Here, Acanthamoeba were recovered on non-nutrient agar plate lawn with E. coli and identified by morphological characteristics of the cyst. Furthermore PCR was performed with genus-specific primers followed by direct sequencing of the PCR product for molecular identification. Overall our PCR and sequencing results confirmed pathogenic genotypes including T4 and T15 from both soil and water samples. This is our first report of Acanthamoeba isolation from both soil and water resources of Pakistan which may serve as a potential treat to human health across the country.

  18. 3D high-density localization microscopy using hybrid astigmatic/ biplane imaging and sparse image reconstruction.

    PubMed

    Min, Junhong; Holden, Seamus J; Carlini, Lina; Unser, Michael; Manley, Suliana; Ye, Jong Chul

    2014-11-01

    Localization microscopy achieves nanoscale spatial resolution by iterative localization of sparsely activated molecules, which generally leads to a long acquisition time. By implementing advanced algorithms to treat overlapping point spread functions (PSFs), imaging of densely activated molecules can improve the limited temporal resolution, as has been well demonstrated in two-dimensional imaging. However, three-dimensional (3D) localization of high-density data remains challenging since PSFs are far more similar along the axial dimension than the lateral dimensions. Here, we present a new, high-density 3D imaging system and algorithm. The hybrid system is implemented by combining astigmatic and biplane imaging. The proposed 3D reconstruction algorithm is extended from our state-of-the art 2D high-density localization algorithm. Using mutual coherence analysis of model PSFs, we validated that the hybrid system is more suitable than astigmatic or biplane imaging alone for 3D localization of high-density data. The efficacy of the proposed method was confirmed via simulation and real data of microtubules. Furthermore, we also successfully demonstrated fluorescent-protein-based live cell 3D localization microscopy with a temporal resolution of just 3 seconds, capturing fast dynamics of the endoplasmic recticulum.

  19. FASTDEF: fast defocus and astigmatism estimation for high-throughput transmission electron microscopy.

    PubMed

    Vargas, J; Otón, J; Marabini, R; Jonic, S; de la Rosa-Trevín, J M; Carazo, J M; Sorzano, C O S

    2013-02-01

    In this work we present a fast and automated algorithm for estimating the contrast transfer function (CTF) of a transmission electron microscope. The approach is very suitable for High Throughput work because: (a) it does not require any initial defocus estimation, (b) it is almost an order of magnitude faster than existing approaches, (c) it opens the way to well-defined extensions to the estimation of higher order aberrations, at the same time that provides defocus and astigmatism estimations comparable in accuracy to well established methods, such as Xmipp and CTFFIND3 approaches. The new algorithm is based on obtaining the wrapped modulating phase of the power spectra density pattern by the use of a quadrature filter. This phase is further unwrapped in order to obtain the continuous and smooth absolute phase map; then a Zernike polynomial fitting is performed and the defocus and astigmatism parameters are determined. While the method does not require an initial estimation of the defocus parameters or any non-linear optimization procedure, these approaches can be used if further refinement is desired. Results of the CTF estimation method are presented for standard negative stained images, cryo-electron microscopy images in the absence of carbon support, as well as micrographs with only ice. Additionally, we have also tested the proposed method with micrographs acquired from tilted and untilted samples, obtaining good results. The algorithm is freely available as a part of the Xmipp package [http://xmipp.cnb.csic.es].

  20. Independent control of beam astigmatism and ellipticity using a SLM for fs-laser waveguide writing.

    PubMed

    Ruiz de la Cruz, A; Ferrer, A; Gawelda, W; Puerto, D; Sosa, M Galván; Siegel, J; Solis, J

    2009-11-01

    We have used a low repetition rate (1 kHz), femtosecond laser amplifier in combination with a spatial light modulator (SLM) to write optical waveguides with controllable cross-section inside a phosphate glass sample. The SLM is used to induce a controllable amount of astigmatism in the beam wavefront while the beam ellipticity is controlled through the propagation distance from the SLM to the focusing optics of the writing set-up. The beam astigmatism leads to the formation of two separate disk-shaped foci lying in orthogonal planes. Additionally, the ellipticity has the effect of enabling control over the relative peak irradiances of the two foci, making it possible to bring the peak irradiance of one of them below the material transformation threshold. This allows producing a single waveguide with controllable cross-section. Numerical simulations of the irradiance distribution at the focal region under different beam shaping conditions are compared to in situ obtained experimental plasma emission images and structures produced inside the glass, leading to a very satisfactory agreement. Finally, guiding structures with controllable cross-section are successfully produced in the phosphate glass using this approach.

  1. Dual quantum cascade laser trace gas instrument with astigmatic Herriott cell at high pass number.

    PubMed

    McManus, J Barry; Zahniser, Mark S; Nelson, David D

    2011-02-01

    We have developed and demonstrated a high-sensitivity trace gas instrument employing two mid-infrared quantum cascade lasers and an astigmatic Herriott sample cell with up to a 240 m path length. Several aspects of astigmatic Herriott cell optics have been addressed to enable operation at a high pass number (up to 554), including aberrations and pattern selection to minimize interference fringes. The new instrument design, based on the 200 m cell, can measure various atmospheric trace gases, depending on the installed lasers, with multiple trace gases measured simultaneously. Demonstrated concentration noise levels (1 s average) are 40 parts per trillion [(ppt) 10(-12)] for formaldehyde, 10 ppt for carbonyl sulfide, 110 ppt for hydrogen peroxide (H2O2), and 180 ppt for nitrous acid (HONO). High-precision measurements of nitrous oxide and methane have been recorded at the same time as high-sensitivity measurements of HONO and H2O2.

  2. Comparison of Two Different Scheimpflug Devices in the Detection of Keratoconus, Regular Astigmatism, and Healthy Corneas

    PubMed Central

    Finis, David; Ralla, Bernhard; Karbe, Maria; Borrelli, Maria; Schrader, Stefan; Geerling, Gerd

    2015-01-01

    Aim. The aim of this study was to determine the intra- and interobserver variability of two Scheimpflug based camera systems, Pentacam and Sirius. In addition, the comparability of the measurements was tested in healthy subjects, subjects with regular astigmatism, and keratoconus patients. Methods. Intra- and interobserver variability were assessed in 20 healthy corneas. Pachymetry values were also compared with ultrasound pachymetry as a reference measurement. To detect possible differences between the two devices, 82 eyes with clinically established keratoconus, 30 eyes with regular astigmatism (>1.5 D), and 60 eyes without corneal pathologies were included in this prospective study. Results. Pachymetry and keratometry showed good intra- and interobserver variability for both devices. Pachymetry values obtained with the Sirius system (579 ± 58 μm) were significantly higher compared to the Pentacam system (551 ± 40 μm, P < 0.001) and to ultrasound pachymetry (550 ± 43 μm, P < 0.001). Significant interdevice differences were found regarding the majority of the detected keratometry parameters. Conclusions. Both devices show almost perfect reproducibility in healthy subjects. However, pachymetry and keratometry values of the two devices should not be used interchangeably. PMID:25954510

  3. Isolation and identification of Acanthamoeba species from natural water sources in the northeastern part of Thailand.

    PubMed

    Thammaratana, Thani; Laummaunwai, Porntip; Boonmars, Thidarut

    2016-04-01

    Acanthamoeba are found in the environment, particularly in water, all over the world. The genus is currently classified into 20 different genotypes, T1-T20. In this study, 63 natural water samples from 11 provinces in northeast Thailand were collected and cultured on non-nutrient agar plates. Positive samples by culture were subsequently analyzed by molecular methods. The identification of Acanthamoeba was based on morphological features and molecular techniques using PCR and DNA sequencing. The results showed that 10 samples out of 63 were positive (15.9 %). Phylogenetic analysis revealed that seven samples were T4, one sample was similar to T3, and the other two samples were similar to T5. This is the first report demonstrating the contamination of Acanthamoeba species in natural water sources in northeast Thailand. PMID:26779920

  4. Lethal Effects of Helianthemum lippii (L.) on Acanthamoeba castellanii Cysts in Vitro

    PubMed Central

    Badria, F.A.; Hetta, M.H.; Sarhan, Rania M.; Ezz El-Din, M.H.

    2014-01-01

    Acanthamoeba spp. commonly cause Acanthamoeba keratitis which is typically associated with the wear of contact lenses. Therefore, finding an economic, efficient, and safe therapy of natural origin is of outmost importance. This study examined the in vitro lethal potential of ethyl acetate and methanol extracts of Helianthemum lippii (L.) (sun roses) against Acanthamoeba castellanii cysts isolated from patients with amoebic keratitis. Both extracts proved to be potent as regard to their lethal effects on A. castellanii cysts with comparable results to chlorhexidine. The ethyl acetate was more promising with cumulative lethality. It showed a highly significant lethal percentage along the duration of treatment. The analysis of the more potent ethyl acetate extract revealed the presence of 2.96 mg/100 g of total phenolics, 0.289 mg/100 ml of total flavonoids and 37 mg/100 mg of total tannins which highlighted their phytomedicinal role. PMID:25031463

  5. In Vitro Effectiveness of Povidone-Iodine on Acanthamoeba Isolates from Human Cornea

    PubMed Central

    Gatti, Simonetta; Cevini, Claudia; Bruno, Antonella; Penso, Gabriella; Rama, Paolo; Scaglia, Massimo

    1998-01-01

    Acanthamoeba keratitis is a severe ocular infection secondary to accidental macro- or microscopic trauma of the cornea. Starting in 1985, a dramatic increase of this infection was recorded along with the spread of contact lens use. This protozoal disease is difficult to treat because of the scarcity of efficacious topical and systemic drugs. We evaluated the in vitro effectiveness of povidone-iodine (PVP-I [Betadine]), an agent with broad antibacterial and antiviral activity, compared to that of chlorhexidine (CXD), a cationic antiseptic, on Acanthamoeba isolates from patients with amebic keratitis. The results showed that PVP-I solution from 0.5 to 2.5% has a better antiamebic activity both on trophic and cystic stages of Acanthamoeba spp. than does CXD. PMID:9736540

  6. Rapid diagnosis of Acanthamoeba keratitis from corneal scrapings using indirect fluorescent antibody staining.

    PubMed

    Epstein, R J; Wilson, L A; Visvesvara, G S; Plourde, E G

    1986-09-01

    Two soft contact lens wearers using a homemade saline solution developed corneal stromal inflammation and epithelial ulceration and were both treated for months with a presumptive diagnosis of herpes simplex keratitis. Subsequently, corneal scrapings revealed refractile, cystic structures consistent with the appearance of Acanthamoeba. This was rapidly confirmed by indirect fluorescent antibody studies, and Acanthamoeba castellani was later identified by growth in culture in both cases. Acanthamoeba is being reported with increasing frequency as a pathogen responsible for chronic stromal keratitis and ulceration in contact lens wearers. Since specific therapy is required to control this organism, rapid diagnosis is essential. Indirect fluorescent antibody staining of corneal scrapings provides a simple means of accomplishing this goal with a high degree of accuracy. PMID:2428344

  7. Internalization of Mycobacterium shottsii and Mycobacterium pseudoshottsii by Acanthamoeba polyphaga.

    PubMed

    Gupta, Tuhina; Fine-Coulson, Kari; Karls, Russell; Gauthier, David; Quinn, Frederick

    2013-08-01

    Amoebae serve as environmental hosts to a variety of mycobacteria, including Mycobacterium avium and Mycobacterium marinum. Mycobacterium shottsii and Mycobacterium pseudoshottsii are waterborne species isolated from the spleens and dermal lesions of striped bass (Morone saxatilis) from the Chesapeake Bay. The optimal growth temperature for these fish isolates is 25 °C. In the present study, amoebae were examined as a potential environmental reservoir for these fish pathogens. Several studies demonstrated that M. avium bacilli replicate within the trophozoite stage and reside in large numbers within the cytosol of the cyst of the free-living amoeba Acanthamoeba polyphaga. Results from the present study showed that M. shottsii, M. pseudoshottsii, and M. marinum bacilli were internalized by A. polyphaga trophozoites within 6 h but that intracellular viability decreased by 2 to 3 logs over 10 days. While an average of 25 M. marinum bacilli were identified by electron microscopy in the cytosol of the cyst, <5 M. pseudoshottsii and no M. shottsii bacilli were observed in this location. All Mycobacterium species examined remained viable but did not replicate after encystment and subsequent 48 h incubation in 4% HCl. This concentration of HCl will kill mycobacteria but will not enter amoebal cysts. Bacterial viability studies within stages of the amoeba life cycle indicate fewer M. shottsii and M. pseudoshottsii bacilli within the trophozoite and cyst stages relative to M. marinum. PMID:23899000

  8. Shiga toxins decrease enterohaemorrhagic Escherichia coli survival within Acanthamoeba castellanii.

    PubMed

    Chekabab, Samuel M; Daigle, France; Charette, Steve J; Dozois, Charles M; Harel, Josée

    2013-07-01

    Enterohaemorrhagic Escherichia coli (EHEC) are zoonotic pathogens transmitted to humans through contaminated water or bovine products. One of the strategies used by pathogenic bacteria to survive in aquatic environments is using free-living amoebae as hosts. Acanthamoeba castellanii is an amoeba known to host several waterborne pathogens. This study investigates the survival of EHEC with A. castellanii, which could contribute to its spread and transmission to humans. We used a gentamicin protection assay as well as fluorescence and electron microscopy to monitor the intra-amoebae survival of EHEC O157:H7 over 24 h. The results showed that EHEC were able to survive within A. castellanii and that this survival was reduced by Shiga toxins (Stx) produced by EHEC. A toxic effect mediated by Stx was demonstrated by amoebae mortality and LDH release during co-culture of EHEC and amoeba. This work describes the ability of EHEC to survive within A. castellanii, and this host-pathogen interaction is partially controlled by the Stx. Thus, this ubiquitous amoeba could represent an environmental niche for EHEC survival and transmission. PMID:23581502

  9. Photoinhibition of Growth in Acanthamoeba castellanii Cultures1

    PubMed Central

    Dolphin, Warren D.

    1970-01-01

    Light from 350 to 680 nm at intensities up to 1.62 × 105 ergs per sec per cm2 slowed exponential growth and lowered the maximum yield in axenic cultures of Acanthamoeba castellanii. Photoinhibition was a linear function of light intensity up to 1.25 × 105 ergs per sec per cm2. At higher intensities, growth was too slow to be measured accurately. A photochemical change occurring in the growth medium on irradiation was a function of light dosage and not intensity per se. Light in dosages which appreciably changed the growth-supporting properties of the medium exceeded the dosages received by exponentially growing cultures during irradiation. Consequently, photoinhibition of growth was attributed to a direct effect of light on the amoebae, not to photodegradation of the medium. The growth-supporting properties of irradiated media could be restored by the addition of yeast extract and Proteose peptone. The reduced growth rate in the light was not due to cyst formation or induction of multinuclearity. Light affected the amoebae either through absorption by intracellular pigment(s) or through binding to the amoebae of a photosensitizing compound in the medium. PMID:5474886

  10. Ultrastructural study of encystation and excystation in Acanthamoeba castellanii.

    PubMed

    Chávez-Munguía, Bibiana; Omaña-Molina, Maritza; González-Lázaro, Mónica; González-Robles, Arturo; Bonilla, Patricia; Martínez-Palomo, Adolfo

    2005-01-01

    Encystation and excystation of Acanthamoeba castellanii were studied by transmission electron microscopy. The differentiation process was induced in asynchronous cultures grown axenically. Cytoplasmic vesicles containing a dense fibrous material very similar in appearance to the cyst wall were observed in trophozoites induced to encyst. When these trophozoites were incubated with calcofluor white m2r, fluorescence was observed in cytoplasmic vesicles, suggesting that the material contained in these vesicles corresponded to cyst wall precursors. Semithin cryosections of mature cysts with the same treatment showed fluorescence in the ectocyst and a less intense fluorescence in the endocyst, suggesting the presence of cellulose in both structures of the cyst wall. In mature cysts induced to excystation, small structures very similar to electron-dense granules (EDG) previously described in other amoebae were frequently observed. The EDGs were either sparsely distributed in the cytoplasm or associated with the cytoplasmic face of the plasma membrane. Many of them were located near the ostiole. In advanced phases of excystation, endocytic activity was suggested by the formation of endocytic structures and the presence of vacuoles with fibrous content similar to that of the cyst wall. Electron-dense granules in the process of dissolution were also observed in these vacuoles. Furthermore, the formation of a pseudopod suggests a displacement of the amoeba toward the ostiole. PMID:15817120

  11. Acanthamoeba royreba: morphological features and in vitro cytopathic effect.

    PubMed

    González-Robles, Arturo; Salazar-Villatoro, Lizbeth; Omaña-Molina, Maritza; Lorenzo-Morales, Jacob; Martínez-Palomo, Adolfo

    2013-04-01

    Observations on cultured Acanthamoeba royreba trophozoites and in vitro cytopathogenicity of this amoeba are described. In culture, amoebae were active, pleomorphic and moved on the substrate by producing endocytic structures and emitting slight cytoplasmic microprojections from the cell surface. These projections were formed by hyaline cytoplasm and they were related to motion structures such as acanthopodia and lamellipodia, in which actin provides a framework that allows rapid changes in morphology. In the cytoplasm abundant vacuoles of different size and content were seen. By means of electron microscopy, it was possible to observe the compact fibrogranular appearance of the cytoplasm, along with the main cellular organelles such as the Golgi complex, the endoplasmic reticulum, digestive vacuoles, mitochondria and contractile vacuoles. Incubation of MDCK epithelial cell monolayers with conditioned medium did not produce a significant structural damage to the monolayer, even after 24h of incubation. When the trophozoites were incubated with the target cells the monolayer exhibited a clear injury created by the amoebae, which produced focal damage. Nevertheless, the rest of the monolayer appeared to remain intact, suggesting that a contact-dependent interaction is necessary to damage the target cells. These observations demonstrate the low invasive capacity of this amoeba. PMID:23357648

  12. Risk factors for acanthamoeba keratitis in contact lens users: a case-control study.

    PubMed Central

    Radford, C. F.; Bacon, A. S.; Dart, J. K.; Minassian, D. C.

    1995-01-01

    OBJECTIVE--To investigate reasons for an increase in cases of Acanthamoeba keratitis related to contact lenses. DESIGN--Case-control study. Cases were contact lens related acanthamoeba keratitis patients treated between 1 September 1989 and 31 August 1992. Controls were lens users without lens related disease who presented as new patients to the casualty department from 1 March 1992 to 31 August 1992. All subjects completed a questionnaire detailing lens use and hygiene practices. SETTING--Eye hospital. SUBJECTS--35 cases with acanthamoeba keratitis and 378 controls. MAIN OUTCOME MEASURES--Relative risks comparing different contact lens types, socioeconomic classification, age, sex, lens use, lens wearing experience, hygiene compliance, and hygiene systems. RESULTS--The crude relative risk for developing acanthamoeba keratitis with the use of daily wear disposable lenses was 49.45 (95% confidence interval 6.53 to 2227; P < 0.001) compared with conventional soft lenses (the referent). Multivariable analysis showed that this increased risk could be largely attributed to lack of disinfection (relative risk 55.86 (10 to 302); P < 0.001) and use of chlorine based disinfection (14.63 (2.8 to 76); P = 0.001) compared with other chemical systems (the referent). None of the other outcome measures showed a significant association. CONCLUSIONS--Both failure to disinfect daily wear soft contact lenses and the use of chlorine release lens disinfection systems, which have little protective effect against the organism, are major risk factors for acanthamoeba keratitis. These risks have been particularly common in disposable lens use. Over 80% of acanthamoeba keratitis could be avoided by the use of lens disinfection systems that are effective against the organism. PMID:7787645

  13. Evaluation of the immunodiagnostic potential of a recombinant surface protein domain from Acanthamoeba castellanii.

    PubMed

    Sánchez, Alemao G Carpinteyro; Virginio, Veridiana Gomes; Maschio, Vinicius José; Ferreira, Henrique Bunselmeyer; Rott, Marilise Brittes

    2016-10-01

    Acanthamoeba spp. are free-living protists widely distributed in environment, able to cause keratitis, encephalitis and skin lesions in humans and animals. Acanthamoeba spp. exist in two forms: an infective trophozoite and a dormant cyst. Several factors contribute to the pathogenesis of Acanthamoeba spp. The parasite adhesion to the host cell is the primary step for infection and is mediated by a mannose binding-protein, expressed in the surface and considered the main pathogenicity factor in Acanthamoeba spp. So far, there was no evidence of another surface protein of Acanthamoeba spp. relevant for host invasion or infection by these organisms. The aims of this study were to identify and characterize an Acanthamoeba castellanii surface protein and to evaluate its diagnostic potential. In silico predictions of surface proteins allowed to identify the A. castellanii calreticulin as a possible surface antigen. The coding sequence of a predicted extracellular domain of A. castellanii calreticulin was cloned by in vivo homologous recombination and the recombinant polypeptide (AcCRT29-130) was produced. Its immunodiagnostic potential was assessed in a recombinant antigen-based ELISA with sera from experimentally infected rats that developed keratitis and encephalitis, and sera from patients with encephalitis. The AcCRT29-130 was significantly more recognized by sera from encephalitis infected rats in comparison with the non-infected controls. Human sera from encephalitis patients, however presented no significant response. These results showed the AcCRT29-130 potential for A. castellanii infection immunodiagnosis in animals, with further studies being required for assessment of its use for human infections.

  14. War of the microbial worlds: who is the beneficiary in Acanthamoeba-bacterial interactions?

    PubMed

    Siddiqui, Ruqaiyyah; Khan, Naveed Ahmed

    2012-04-01

    Acanthamoeba hosts diverse microbial organisms including viruses, bacteria, yeast and protists, some of which are potential human pathogens. The precise nature of this symbiosis is not clear, but it is suggested that such interactions enable pathogenic microbes to survive hostile conditions and lead to their transmission to susceptible hosts to establish infection. In particular, Acanthamoeba-bacteria interactions have gained significant attention by the scientific and the medical community and have led to speculations of employing anti-amoebic approaches in eradicating 'superbugs' from clinical settings. Here, we discuss the nature of these convoluted interactions and the benefit they represent for the symbionts.

  15. Novel Acanthamoeba 18S rRNA gene sequence type from an environmental isolate.

    PubMed

    Magnet, A; Henriques-Gil, N; Galván-Diaz, A L; Izquiedo, F; Fenoy, S; del Aguila, C

    2014-08-01

    The free-living amoebae, Acanthamoeba, can act as opportunistic parasites on a wide range of vertebrates and are becoming a serious threat to human health due to the resistance of their cysts to harsh environmental conditions, disinfectants, some water treatment practices, and their ubiquitous distribution. Subgenus classification based on morphology is being replaced by a classification based on the sequences of the 18S rRNA gene with a total of 18 different genotypes (T1-T18). A new environmental strain of Acanthamoeba isolated from a waste water treatment plant is presented in this study as a candidate for the description of the novel genotype T19 after phylogenetic analysis.

  16. Analytical expressions for field astigmatism in decentered two mirror telescopes and application to the collimation of the ESO VLT

    NASA Astrophysics Data System (ADS)

    Noethe, L.; Guisard, S.

    2000-05-01

    We derive formulae for all parameters defining the field astigmatism of misaligned two mirror telescopes with arbitrary geometries and with stop positions anywhere on the line connecting the vertices of the two mirrors. The formulae show explicitly the dependence of the field astigmatism on the fundamental design parameters and characteristics of the telescope and on the stop position. Special attention is given to the particular case where such a schiefspiegler has been corrected for coma at the field center. In addition, we study the effects of the practical definition that the center of the field is the center of the adapter. Following a recent paper by McLeod, where the field dependence of astigmatism is used to collimate a Ritchey-Chretien telescope with the stop at the primary mirror, we apply our formulae to the Cassegrain focus of the ESO Very Large Telescope (VLT), where the stop is at the secondary mirror and the telescope is only corrected for spherical aberration. We present measurements of the field astigmatism and discuss the accuracy of the collimation method.

  17. Astigmatism management in cataract surgery with Precizon® toric intraocular lens: a prospective study

    PubMed Central

    Vale, Carolina; Menezes, Carlos; Firmino-Machado, J; Rodrigues, Pedro; Lume, Miguel; Tenedório, Paula; Menéres, Pedro; Brochado, Maria do Céu

    2016-01-01

    Purpose The purpose of this study was to evaluate the visual and refractive outcomes and rotational stability of the new aspheric Precizon® toric intraocular lens (IOL) for the correction of corneal astigmatism in cataract surgery. Setting Department of Ophthalmology, Hospital Geral de Santo António – Centro Hospitalar do Porto, EPE and Hospital de Pedro Hispano, Matosinhos, Portugal. Design This was a prospective clinical study. Patients and methods A total of 40 eyes of 27 patients with corneal astigmatism greater than 1.0 diopter (D) underwent cataract surgery with implantation of Precizon® toric IOL. IOL power calculation was performed using optical coherence biometry (IOLMaster®). Outcomes of uncorrected (UDVA) and best-spectacle corrected distance visual acuities (BCDVA), refraction, and IOL rotation were analyzed at the 1st week, 1st, 3rd, and 6th month’s evaluations. Results The median postoperative UDVA was better than preoperative best-spectacle corrected distance visual acuity (0.02 [0.06] logMAR vs 0.19 [0.20] logMAR, P<0.001). At 6 months, postoperative UDVA was 0.1 logMAR or better in 95% of the eyes. At last follow-up, the mean spherical equivalent was reduced from −3.35±3.10 D to −0.02±0.30 D (P<0.001) with 97.5% of the eyes within ±0.50 D of emmetropia. The mean preoperative keratometric cylinder was 2.34±0.95 D and the mean postoperative refractive cylinder was 0.24±0.27 D (P<0.001). The mean IOL rotation was 2.43°±1.55°. None of the IOLs required realignment. Conclusion Precizon® toric IOL revealed very good rotational stability and performance regarding predictability, efficacy, and safety in the correction of preexisting regular corneal astigmatism associated with cataract surgery. PMID:26855559

  18. Higher-order aberrations and best-corrected visual acuity in Native American children with a high prevalence of astigmatism

    PubMed Central

    Miller, Joseph M.; Harvey, Erin M.; Schwiegerling, Jim

    2016-01-01

    Purpose To determine whether higher-order aberrations (HOAs) in children from a highly astigmatic population differ from population norms and whether HOAs are associated with astigmatism and reduced best-corrected visual acuity. Methods Subjects were 218 Tohono O’odham Native American children 5–9 years of age. Noncycloplegic HOA measurements were obtained with a handheld Shack-Hartmann sensor (SHS). Signed (z06s to z14s) and unsigned (z06u to z14u) wavefront aberration Zernike coefficients Z(3,−3) to Z(4,4) were rescaled for a 4 mm diameter pupil and compared to adult population norms. Cycloplegic refraction and best-corrected logMAR letter visual acuity (BCVA) were also measured. Regression analyses assessed the contribution of astigmatism (J0) and HOAs to BCVA. Results The mean root-mean-square (RMS) HOA of 0.191 ± 0.072 μm was significantly greater than population norms (0.100 ± 0.044 μm. All unsigned HOA coefficients (z06u to z14u) and all signed coefficients except z09s, z10s, and z11s were significantly larger than population norms. Decreased BCVA was associated with astigmatism (J0) and spherical aberration (z12u) but not RMS coma, with the effect of J0 about 4 times as great as z12u. Conclusions Tohono O’odham children show elevated HOAs compared to population norms. Astigmatism and unsigned spherical aberration are associated with decreased acuity, but the effects of spherical aberration are minimal and not clinically significant. PMID:26239206

  19. Extended wavelet transformation to digital holographic reconstruction: application to the elliptical, astigmatic Gaussian beams.

    PubMed

    Remacha, Clément; Coëtmellec, Sébastien; Brunel, Marc; Lebrun, Denis

    2013-02-01

    Wavelet analysis provides an efficient tool in numerous signal processing problems and has been implemented in optical processing techniques, such as in-line holography. This paper proposes an improvement of this tool for the case of an elliptical, astigmatic Gaussian (AEG) beam. We show that this mathematical operator allows reconstructing an image of a spherical particle without compression of the reconstructed image, which increases the accuracy of the 3D location of particles and of their size measurement. To validate the performance of this operator we have studied the diffraction pattern produced by a particle illuminated by an AEG beam. This study used mutual intensity propagation, and the particle is defined as a chirped Gaussian sum. The proposed technique was applied and the experimental results are presented.

  20. Focal plane internal energy flows of singular beams in astigmatically aberrated low numerical aperture systems.

    PubMed

    Bahl, Monika; Senthilkumaran, P

    2014-09-01

    Singular beams have circulating energy components. When such beams are focused by low numerical aperture systems suffering from astigmatic aberration, these circulating energy components get modified. The phase gradient introduced by this type of aberration splits the higher charge vortices. The dependence of the charge, the aberration coefficient, and the size of the aperture on the nature of the splitting process are reported in this paper. The transverse components of the Poynting vector fields that can be derived from the phase gradient vector field distributions are further decomposed into solenoidal and irrotational components using the Helmholtz-Hodge decomposition method. The solenoidal components relate to the orbital angular momentum of the beams, and the irrotational components are useful in the transport of intensity equations for phase retrieval.

  1. Advanced astigmatism-corrected Czerny-Turner imaging spectrometer in spectral broadband

    NASA Astrophysics Data System (ADS)

    Cong, Hai-fang

    2014-12-01

    This paper reports an advanced Czerny-Turner optical structure which is used for the application in imaging spectrometers. To obtain the excellent imaging quality, a cylindrical lens with a wedge angle is used between the focusing mirror and the imaging plane to remove astigmatism in broadband. It makes the advanced optical system presents high resolution over the full bandwidth and decreases the cost. An example of the imaging spectrometer in the waveband of 260nm~520nm has been designed to prove our theory. It yields the excellent modulation transfer functions (MTF) of all fields of view which are more than 0.75 over the broadband under the required Nyquist frequency (20lp/mm).

  2. Astigmatic visual and deprivation in cat: behavioral, optical and retinophysiological consequences.

    PubMed

    Thibos, L N; Levick, W R

    1982-01-01

    Kittens were deprived of clear vision in one eye only by +7D or -7D cylindrical lenses worn from eye opening until 7.5 months of age. Behavioral measurements subsequently demonstrated diminished acuity through the affected eye relative to the opposite control eye. However, single unit recordings at 3.5 years of age from retinal ganglion cells located within 1-11 degrees of the centre of the area centralis showed neither loss of grating resolution nor any abnormal orientation bias. Furthermore, the astigmatic rearing had minimal effect on the development of the cat's natural optics to the emmetropic state. The experiments indicate that the amblyopic defect induced by the cylindrical lenses occurs in the brain rather than the eye. PMID:7101750

  3. [Orthokeratology for the high myopia and high astigmatism is worth watching].

    PubMed

    Xie, Peiying

    2015-01-01

    The prevalence of high myopia in teenagers is rising. Due to both genetic factors and environmental factors, most of myopia occurs in early age with rapid progress, and the prevention and control are very difficult. Orthokeratology is considered as one of the most effective ways of controlling myopia for children. It is proved effective through many years of clinical studies not only for low to moderate myopia, but also for high myopia with astigmatism. However, professional knowledge is lacking domestically. This paper introduces the local and overseas research results in recent years, and discusses the necessity and feasibility of high diopter orthokeratology correction, implementation methods and requirements, and safety and effectiveness evaluation standards for reference.

  4. [Orthokeratology for the high myopia and high astigmatism is worth watching].

    PubMed

    Xie, Peiying

    2015-01-01

    The prevalence of high myopia in teenagers is rising. Due to both genetic factors and environmental factors, most of myopia occurs in early age with rapid progress, and the prevention and control are very difficult. Orthokeratology is considered as one of the most effective ways of controlling myopia for children. It is proved effective through many years of clinical studies not only for low to moderate myopia, but also for high myopia with astigmatism. However, professional knowledge is lacking domestically. This paper introduces the local and overseas research results in recent years, and discusses the necessity and feasibility of high diopter orthokeratology correction, implementation methods and requirements, and safety and effectiveness evaluation standards for reference. PMID:25877704

  5. Extended wavelet transformation to digital holographic reconstruction: application to the elliptical, astigmatic Gaussian beams.

    PubMed

    Remacha, Clément; Coëtmellec, Sébastien; Brunel, Marc; Lebrun, Denis

    2013-02-01

    Wavelet analysis provides an efficient tool in numerous signal processing problems and has been implemented in optical processing techniques, such as in-line holography. This paper proposes an improvement of this tool for the case of an elliptical, astigmatic Gaussian (AEG) beam. We show that this mathematical operator allows reconstructing an image of a spherical particle without compression of the reconstructed image, which increases the accuracy of the 3D location of particles and of their size measurement. To validate the performance of this operator we have studied the diffraction pattern produced by a particle illuminated by an AEG beam. This study used mutual intensity propagation, and the particle is defined as a chirped Gaussian sum. The proposed technique was applied and the experimental results are presented. PMID:23385926

  6. Effect of location of opening incision on astigmatic correction after small-incision lenticule extraction

    PubMed Central

    Chan, Tommy C. Y.; Ng, Alex LK; Cheng, George P. M.; Wang, Zheng; Woo, Victor C. P.; Jhanji, Vishal

    2016-01-01

    We compared the visual and refractive outcomes between 2 different incisional sites in small incision lenticule extraction (SMILE) for low myopic astigmatism. This was a contralateral eye study. Consecutive cases that underwent bilateral SMILE surgery were included. Procedures for both eyes were identical apart from the location of opening incision. The incision was set on the temporal side for the right eye (Group 1), while a superior incision was set for the left eye (Group 2). Twenty-nine patients with a mean age of 35.0 ± 9.6 years were included. Preoperative visual and refractive parameters were comparable between the 2 groups (p > 0.250). At 3 months, the logMAR uncorrected distance visual acuity was 0.074 ± 0.090 in Group 1 and 0.084 ± 0.130 in Group 2 (p = 0.861). No difference was found in the postoperative manifest spherical equivalent (p = 0.501) and manifest cylinder (p = 0.178) between the 2 groups. The efficacy index was 0.85 ± 0.16 in Group 1 and 0.85 ± 0.20 in Group 2 (p = 0.828). Astigmatic correction was not significantly affected by the location of opening incisions using vector analysis. Our study did not find significant differences in visual and refractive outcomes with temporal or superior opening incision during SMILE surgery. PMID:27775085

  7. [Efficiency of interlamellar refractive tunnel keratoplasty in myopia and astigmatism correction].

    PubMed

    Shusterov, Y

    2014-10-01

    Correction of high degree myopia, anisometropia and astigmatism continues to remain one of actual problems of ophthalmology. The purpose of the present work - the analysis of results of application of refractive interlamellar tunnel keratoplasty variants. We develop 6 updatings tunnel keratoplasty. In total in clinic 310 operations from which in 158 cases as a transfer material used a donor cornea, in 63 cases - brephocornea (a fruit cornea) and in 89 cases - hydrogel synthetic implant, modified in low-temperature to gas-discharge plasma are spent. From the specified number of operative interventions, on 86 eyes of operation tunnel keratoplasty have been spent at those patients by whom earlier it has been given up in carrying out eximerlaser corrections, in connection with presence of a "thin", "flat" and "convex" cornea. Maximum refractive effect fell first two weeks after operation. Definitive stabilisation of a refraction occurred on 2-3 month, thus regress of the reached effect made an order of 10-12 %. It is reached refractive effect from 5,5 to 20,0 D. Undercorrection in some cases made to 3,5 D, that spoke very high myopia (more than 20,0 D) degrees. It has been noticed, that refractive effect of operations with ecsplants was above (on the average on 10 %), than at use of a donor cornea, at identical cross-section section of used transfer materials. It spoke that the synthetic material, unlike a donor cornea, kept the form. At all patients substantial increase of visual acuities has been received, and in 75 % it was equal or exceeded visual acuity before operation with the greatest possible correction. Thus, clinical approbation has proved, that the variants of tunnel keratoplasty, are effective ways of high myopia, anisometropia and astigmatism correction. Updating in gaseous plasma is represented in the perspective way of improvement of biocompatibility of synthetic materials.

  8. Interactions between Human Norovirus Surrogates and Acanthamoeba spp.

    PubMed

    Hsueh, Tun-Yun; Gibson, Kristen E

    2015-06-15

    Human noroviruses (HuNoVs) are the most common cause of food-borne disease outbreaks, as well as virus-related waterborne disease outbreaks in the United States. Here, we hypothesize that common free-living amoebae (FLA)-ubiquitous in the environment, known to interact with pathogens, and frequently isolated from water and fresh produce-could potentially act as reservoirs of HuNoV and facilitate the environmental transmission of HuNoVs. To investigate FLA as reservoirs for HuNoV, the interactions between two Acanthamoeba species, A. castellanii and A. polyphaga, as well as two HuNoV surrogates, murine norovirus type 1 (MNV-1) and feline calicivirus (FCV), were evaluated. The results showed that after 1 h of amoeba-virus incubation at 25°C, 490 and 337 PFU of MNV-1/ml were recovered from A. castellanii and A. polyphaga, respectively, while only few or no FCVs were detected. In addition, prolonged interaction of MNV-1 with amoebae was investigated for a period of 8 days, and MNV-1 was demonstrated to remain stable at around 200 PFU/ml from day 2 to day 8 after virus inoculation in A. castellanii. Moreover, after a complete amoeba life cycle (i.e., encystment and excystment), infectious viruses could still be detected. To determine the location of virus associated with amoebae, immunofluorescence experiments were performed and showed MNV-1 transitioning from the amoeba surface to inside the amoeba over a 24-h period. These results are significant to the understanding of how HuNoVs may interact with other microorganisms in the environment in order to aid in its persistence and survival, as well as potential transmission in water and to vulnerable food products such as fresh produce. PMID:25841006

  9. Interactions between Human Norovirus Surrogates and Acanthamoeba spp.

    PubMed Central

    Hsueh, Tun-Yun

    2015-01-01

    Human noroviruses (HuNoVs) are the most common cause of food-borne disease outbreaks, as well as virus-related waterborne disease outbreaks in the United States. Here, we hypothesize that common free-living amoebae (FLA)—ubiquitous in the environment, known to interact with pathogens, and frequently isolated from water and fresh produce—could potentially act as reservoirs of HuNoV and facilitate the environmental transmission of HuNoVs. To investigate FLA as reservoirs for HuNoV, the interactions between two Acanthamoeba species, A. castellanii and A. polyphaga, as well as two HuNoV surrogates, murine norovirus type 1 (MNV-1) and feline calicivirus (FCV), were evaluated. The results showed that after 1 h of amoeba-virus incubation at 25°C, 490 and 337 PFU of MNV-1/ml were recovered from A. castellanii and A. polyphaga, respectively, while only few or no FCVs were detected. In addition, prolonged interaction of MNV-1 with amoebae was investigated for a period of 8 days, and MNV-1 was demonstrated to remain stable at around 200 PFU/ml from day 2 to day 8 after virus inoculation in A. castellanii. Moreover, after a complete amoeba life cycle (i.e., encystment and excystment), infectious viruses could still be detected. To determine the location of virus associated with amoebae, immunofluorescence experiments were performed and showed MNV-1 transitioning from the amoeba surface to inside the amoeba over a 24-h period. These results are significant to the understanding of how HuNoVs may interact with other microorganisms in the environment in order to aid in its persistence and survival, as well as potential transmission in water and to vulnerable food products such as fresh produce. PMID:25841006

  10. Interactions between Human Norovirus Surrogates and Acanthamoeba spp.

    PubMed

    Hsueh, Tun-Yun; Gibson, Kristen E

    2015-06-15

    Human noroviruses (HuNoVs) are the most common cause of food-borne disease outbreaks, as well as virus-related waterborne disease outbreaks in the United States. Here, we hypothesize that common free-living amoebae (FLA)-ubiquitous in the environment, known to interact with pathogens, and frequently isolated from water and fresh produce-could potentially act as reservoirs of HuNoV and facilitate the environmental transmission of HuNoVs. To investigate FLA as reservoirs for HuNoV, the interactions between two Acanthamoeba species, A. castellanii and A. polyphaga, as well as two HuNoV surrogates, murine norovirus type 1 (MNV-1) and feline calicivirus (FCV), were evaluated. The results showed that after 1 h of amoeba-virus incubation at 25°C, 490 and 337 PFU of MNV-1/ml were recovered from A. castellanii and A. polyphaga, respectively, while only few or no FCVs were detected. In addition, prolonged interaction of MNV-1 with amoebae was investigated for a period of 8 days, and MNV-1 was demonstrated to remain stable at around 200 PFU/ml from day 2 to day 8 after virus inoculation in A. castellanii. Moreover, after a complete amoeba life cycle (i.e., encystment and excystment), infectious viruses could still be detected. To determine the location of virus associated with amoebae, immunofluorescence experiments were performed and showed MNV-1 transitioning from the amoeba surface to inside the amoeba over a 24-h period. These results are significant to the understanding of how HuNoVs may interact with other microorganisms in the environment in order to aid in its persistence and survival, as well as potential transmission in water and to vulnerable food products such as fresh produce.

  11. Impact of free-living amoebae on presence of Parachlamydia acanthamoebae in the hospital environment and its survival in vitro without requirement for amoebae.

    PubMed

    Fukumoto, Tatsuya; Matsuo, Junji; Hayashi, Yasuhiro; Hayashi, Masahiro; Oguri, Satoshi; Nakamura, Shinji; Mizutani, Yoshihiko; Yao, Takashi; Akizawa, Kouzi; Suzuki, Haruki; Shimizu, Chikara; Matsuno, Kazuhiko; Yamaguchi, Hiroyuki

    2010-09-01

    Parachlamydia acanthamoebae is an obligately intracellular bacterium that infects free-living amoebae and is a potential human pathogen in hospital-acquired pneumonia. We examined whether the presence of P. acanthamoebae is related to the presence of Acanthamoeba in an actual hospital environment and assessed the in vitro survival of P. acanthamoebae. Ninety smear samples were collected between November 2007 and March 2008 (trial 1, n = 52) and between October 2008 and February 2009 (trial 2, n = 38) from the floor (dry conditions, n = 56) and sink outlets (moist conditions, n = 34) of a hospital. The prevalences of P. acanthamoebae DNA in the first and second trials were 64.3% and 76%, respectively. The prevalences of Acanthamoeba DNA in the first and second trials were 48% and 63.1%, respectively. A statistical correlation between the prevalence of P. acanthamoebae and that of Acanthamoeba was found (trial 1, P = 0.011; trial 2, P = 0.022), and that correlation increased when samples from just the dry area (floor smear samples, P = 0.002) were analyzed but decreased when samples from a moist area were analyzed (P = 0.273). The in vitro experiment showed that, without Acanthamoeba, P. acanthamoebae could not survive in dry conditions for 3 days at 30 degrees C or 15 days at 15 degrees C. Thus, both organisms were coincidentally found in an actual hospital environment, with the presence of Acanthamoeba having a significant effect on the long-term survival of P. acanthamoebae, suggesting that this potential human pathogen could spread through a hospital environment via Acanthamoeba.

  12. Isolation and identification of Acanthamoeba spp. from thermal swimming pools and spas in Southern Brazil.

    PubMed

    Fabres, Laura Fuhrich; Rosa Dos Santos, Sayonara Peixoto; Benitez, Lisianne Brittes; Rott, Marilise Brittes

    2016-03-01

    Free-living amoebae (FLA) are widely distributed in soil and water. A few number of them are implicated in human disease: Acanthamoeba spp., Naegleria fowleri, Balamuthia mandrillaris and Sappinia diploidea. Species of Acanthamoeba can cause keratitis and brain infections. In this study, 72 water samples were taken from both hot tubs and thermal swimming pools in the city of Porto Alegre, RS, Brazil, to determine the presence of Acanthamoeba in the water as well as perform the phenotypic and genotypic characterization of the isolates. The identification of the isolates was based on the cysts morphology and PCR amplification using genus-specific oligonucleotides. When the isolates were submitted to PCR reaction only 8 were confirmed as belonging to the genus Acanthamoeba. The sequences analysis when compared to the sequences in the GenBank, showed genotype distribution in group T3 (12,5%), T5 (12,5%), T4 (25%) and T15 (50%). The results of this study confirmed the presence of potentially pathogenic isolates of free living amoebae in hot swimming pool and spas which can present risks to human health. PMID:27078644

  13. Essential Role for an M17 Leucine Aminopeptidase in Encystation of Acanthamoeba castellanii

    PubMed Central

    Lee, Yu-Ran; Na, Byoung-Kuk; Moon, Eun-Kyung; Song, Su-Min; Joo, So-Young; Kong, Hyun-Hee; Goo, Youn-Kyoung; Chung, Dong-Il; Hong, Yeonchul

    2015-01-01

    Encystation of Acanthamoeba leads to the formation of resilient cysts from vegetative trophozoites. This process is essential for parasite survival under unfavorable conditions such as starvation, low temperatures, and exposure to biocides. During encystation, a massive turnover of intracellular components occurs, and a large number of organelles and proteins are degraded by proteases. Previous studies with specific protease inhibitors have shown that cysteine and serine proteases are involved in encystation of Acanthamoeba, but little is known about the role of metalloproteases in this process. Here, we have biochemically characterized an M17 leucine aminopeptidase of Acanthamoeba castellanii (AcLAP) and analyzed its functional involvement in encystation of the parasite. Recombinant AcLAP shared biochemical properties such as optimal pH, requirement of divalent metal ions for activity, substrate specificity for Leu, and inhibition profile by aminopeptidase inhibitors and metal chelators with other characterized M17 family LAPs. AcLAP was highly expressed at a late stage of encystation and mainly localized in the cytoplasm of A. castellanii. Knockdown of AcLAP using small interfering RNA induced a decrease of LAP activity during encystation, a reduction of mature cyst formation, and the formation of abnormal cyst walls. In summary, these results indicate that AcLAP is a typical M17 family enzyme that plays an essential role during encystation of Acanthamoeba. PMID:26075721

  14. Molecular Characterization of Pathogenic Acanthamoeba Isolated from Drinking and Recreational water in East Azerbaijan, Northwest Iran.

    PubMed

    Behniafar, Hamed; Niyyati, Maryam; Lasjerdi, Zohreh

    2015-01-01

    Acanthamoeba- related infections, such as amoebic keratitis and granulomatous amoebic encephalitis, can develop in high-risk population through contaminated water sources. Thus, surveying water resources, particularly those available for human use, is of the utmost importance. In the present study, 67 water samples were collected from water resources in East Azerbaijan, a province in northwestern Iran. Samples were cultured on enriched non-nutrient agar plates, and sequencing-based approaches were used for genotyping. The pathogenic potential of the isolates was determined using thermo- and osmo-tolerance tests. Acanthamoeba were detected in 17 (25.4%) of the 67 collected samples. Sequencing analysis revealed that the isolates belonged to the T3 (23.52%), mixed T3/T4 (5.88%), T4 (58.82%), T5 (5.88%), and T13 (5.88%) genotypes. Through thermo- and osmo-tolerance tests, 88.23% of isolates were resistant to 37 °C, 40 °C temperature, and 0.5 M and 1 M osmolarity; thus, these isolates had the potential for pathogenicity. These findings point toa serious public health concern in the studied region. This study is the first to report Acanthamoeba isolated from drinking and recreational water sources in East Azerbaijan and Acanthamoeba T13 isolated from tap water in Iran. PMID:26157334

  15. Molecular Characterization of Pathogenic Acanthamoeba Isolated from Drinking and Recreational water in East Azerbaijan, Northwest Iran

    PubMed Central

    Behniafar, Hamed; Niyyati, Maryam; Lasjerdi, Zohreh

    2015-01-01

    Acanthamoeba- related infections, such as amoebic keratitis and granulomatous amoebic encephalitis, can develop in high-risk population through contaminated water sources. Thus, surveying water resources, particularly those available for human use, is of the utmost importance. In the present study, 67 water samples were collected from water resources in East Azerbaijan, a province in northwestern Iran. Samples were cultured on enriched non-nutrient agar plates, and sequencing-based approaches were used for genotyping. The pathogenic potential of the isolates was determined using thermo- and osmo-tolerance tests. Acanthamoeba were detected in 17 (25.4%) of the 67 collected samples. Sequencing analysis revealed that the isolates belonged to the T3 (23.52%), mixed T3/T4 (5.88%), T4 (58.82%), T5 (5.88%), and T13 (5.88%) genotypes. Through thermo- and osmo-tolerance tests, 88.23% of isolates were resistant to 37 °C, 40 °C temperature, and 0.5 M and 1 M osmolarity; thus, these isolates had the potential for pathogenicity. These findings point toa serious public health concern in the studied region. This study is the first to report Acanthamoeba isolated from drinking and recreational water sources in East Azerbaijan and Acanthamoeba T13 isolated from tap water in Iran. PMID:26157334

  16. Isolation of Acanthamoeba Spp. from Drinking Waters in Several Hospitals of Iran

    PubMed Central

    Bagheri, HR; Shafiei, R; Shafiei, F; Sajjadi, SA

    2010-01-01

    Background Acanthamoeba is an opportunistic amphizoic protozoan found in different water sources including swimming pool as well as in sewage. The aim of this study was to investigate the prevalence of Acanthamoeba in tap-water samples in Iran. Method In this descriptive cross-sectional study, 94 samples of cold and warm tap-water were collected from different wards of hospitals in 13 cities of Iran in 2007–2008. Free residual chlorine, pH, and temperature of samples were measured. After filtration through multipore nylon membrane, samples were cultured on non-nutrient agar. Then we investigated existence of Acanthamoeba by reverse contrast phase microscope. Results Acanthamoeba was found in 45 samples (48%). Thirty-four and 11 positive samples were collected from cold and warm tap water, respectively. The samples belonged to the category of 20–30°C temperature with 0–2 ppm free residual chlorine and pH 6–7.4 showed the most coincidence to the positive cases. The greatest proportion of positive samples was obtained from Mashhad hospitals, while all samples collected from Arak and Semnan hospitals were negative. Conclusion considering the results of this study and the pathogenic role of this protozoan on patients with immunodeficiency, as well as capability of this microorganism in carrying other pathogens such as Legionella, further studies are needed. What is more important, potable water in hospitals should follow the procedure of treatment and sanitation, in order to prevent the relevant nosocomial infections. PMID:22347240

  17. Occurrence of pathogenic Acanthamoeba genotypes in nasal swabs of cancer patients in Iran.

    PubMed

    Memari, Fatemeh; Niyyati, Maryam; Haghighi, Ali; Seyyed Tabaei, Seyyed Javad; Lasjerdi, Z

    2015-05-01

    Incidences of Acanthamoeba granulomatous encephalitis (AGE) have been increased due to a rise in the number of high-risk people, such as immunodeficient patients. Indeed, immunosuppress situation can render the patient in acquiring opportunistic Acanthamoeba infections. In this study, analysis was carried out to verify the presence of free-living amoebae of Acanthamoeba genus in nasal swabs of cancer patients in hospitals of Tehran, Iran. Detection of isolates was based on morphotyping and PCR sequencing of the Diagnostic Fragment 3 (DF3) to identify strains at the genotype level. In addition, the pathogenic potential of the isolates was assayed using temperature and osmotolerance assays. The obtained results revealed that nine isolated strains belonging to T4 genotype-exhibited pathogenic potential. After sequencing, genotype T4 was found to be the most common one in the samples included in this study. Genotype T3 and T5 were also identified. To the best of our knowledge, this is the first study on the typing of Acanthamoeba strains at the genotype level in cancer patients in Iran and worldwide.

  18. Developmental changes in the localization of calcium binding sites in Acanthamoeba castellanii.

    PubMed

    Sobota, A; Przelecka, A

    1981-01-01

    Vegetative cells of Acanthamoeba castellanii have the ability to bind calcium on the plasma membrane in form of the electron-dense deposits. The appearance of the deposits depends on the age of Acanthamoeba culture. In 24-h-old culture the deposits are very small, with diameter of 26 nm. During aging of culture, at both logarithmic and stationary growth phases, the diameter of deposits is larger (70-80 nm), while the deposits are localized only on the plasma membrane. During differentiation of Acanthamoeba cells into cysts electron-dense deposits with a diameter of about 170 nm appear in the mitochondria, whereas no deposits are observed on the plasma membrane. However, at the first stage of differentiation electron-dense material together with extruded membraneous fragments are also observed outside of some newly-formed young cysts. These results suggest that in Acanthamoeba cells, depending on the stage of life cycle, either plasma membrane or mitochondria may be involved in storage of excess cellular calcium. PMID:7228741

  19. Acanthamoeba Encephalitis: Isolation of Genotype T1 in Mycobacterial Liquid Culture Medium

    PubMed Central

    Azzam, Rula; Badenoch, Paul R.; Francis, Michelle J.; Fernandez, Charles; Adamson, Penelope J.; Dendle, Claire; Woolley, Ian; Robson, Jenny; Korman, Tony M.

    2014-01-01

    We report a case of Acanthamoeba encephalitis diagnosed from an antemortem brain biopsy specimen, where the organism was first isolated in mycobacterial liquid medium and first identified by using a sequence generated by a commercial panfungal sequencing assay. We correlate susceptibility results with clinical outcome. PMID:25502534

  20. Isolation and identification of Acanthamoeba spp. from thermal swimming pools and spas in Southern Brazil.

    PubMed

    Fabres, Laura Fuhrich; Rosa Dos Santos, Sayonara Peixoto; Benitez, Lisianne Brittes; Rott, Marilise Brittes

    2016-03-01

    Free-living amoebae (FLA) are widely distributed in soil and water. A few number of them are implicated in human disease: Acanthamoeba spp., Naegleria fowleri, Balamuthia mandrillaris and Sappinia diploidea. Species of Acanthamoeba can cause keratitis and brain infections. In this study, 72 water samples were taken from both hot tubs and thermal swimming pools in the city of Porto Alegre, RS, Brazil, to determine the presence of Acanthamoeba in the water as well as perform the phenotypic and genotypic characterization of the isolates. The identification of the isolates was based on the cysts morphology and PCR amplification using genus-specific oligonucleotides. When the isolates were submitted to PCR reaction only 8 were confirmed as belonging to the genus Acanthamoeba. The sequences analysis when compared to the sequences in the GenBank, showed genotype distribution in group T3 (12,5%), T5 (12,5%), T4 (25%) and T15 (50%). The results of this study confirmed the presence of potentially pathogenic isolates of free living amoebae in hot swimming pool and spas which can present risks to human health.

  1. Amebicidal activity of plant extracts from Southeast Asia on Acanthamoeba spp.

    PubMed

    Chu, D M; Miles, H; Toney, D; Ngyuen, C; Marciano-Cabral, F

    1998-09-01

    The effect of 100 polar and 100 nonpolar plant extract materials obtained from Southeast Asia were evaluated for amebicidal activity in vitro against three species of Acanthamoeba. A. culbertsoni, A. castellanii, and A. polyphaga, the causative agents of granulomatous amebic encephalitis and amebic keratitis, were studied in vitro to determine whether the plant extracts exhibited amebicidal activity or induced encystment of the amebae. Of the 200 plant extracts tested, extracts obtained from three plants (Ipomoea sp., Kaempferia galanga, and Cananga odorata) were amebicidal for all three species of Acanthamoeba and a fourth extract prepared from Gastrochilus panduratum was lytic for A. polyphaga and growth-inhibitory for A. castellanii and A. culbertsoni. Three plant extracts induced encystment of all three species of Acanthamoeba. Select plant extracts were tested as well for tumoricidal activity against B103 neuroblastoma cells. Some plant extracts that exhibited tumoricidal activity for B103 cells were not amebicidal for Acanthamoeba spp. Additionally, the polar and nonpolar extracts that exhibited amebicidal activity were also tested for activity against primary murine peritoneal macrophage cultures. Plant extracts that demonstrated tumoricidal or amebicidal activity were not lytic for normal macrophage cultures. PMID:9766904

  2. Genetic Characterization of Clinical Acanthamoeba Isolates from Japan using Nuclear and Mitochondrial Small Subunit Ribosomal RNA

    PubMed Central

    Rahman, Md Moshiur; Yagita, Kenji; Kobayashi, Akira; Oikawa, Yosaburo; Hussein, Amjad I.A.; Matsumura, Takahiro

    2013-01-01

    Because of an increased number of Acanthamoeba keratitis (AK) along with associated disease burdens, medical professionals have become more aware of this pathogen in recent years. In this study, by analyzing both the nuclear 18S small subunit ribosomal RNA (18S rRNA) and mitochondrial 16S rRNA gene loci, 27 clinical Acanthamoeba strains that caused AK in Japan were classified into 3 genotypes, T3 (3 strains), T4 (23 strains), and T5 (one strain). Most haplotypes were identical to the reference haplotypes reported from all over the world, and thus no specificity of the haplotype distribution in Japan was found. The T4 sub-genotype analysis using the 16S rRNA gene locus also revealed a clear sub-conformation within the T4 cluster, and lead to the recognition of a new sub-genotype T4i, in addition to the previously reported sub-genotypes T4a-T4h. Furthermore, 9 out of 23 strains in the T4 genotype were identified to a specific haplotype (AF479533), which seems to be a causal haplotype of AK. While heterozygous nuclear haplotypes were observed from 2 strains, the mitochondrial haplotypes were homozygous as T4 genotype in the both strains, and suggested a possibility of nuclear hybridization (mating reproduction) between different strains in Acanthamoeba. The nuclear 18S rRNA gene and mitochondrial 16S rRNA gene loci of Acanthamoeba spp. possess different unique characteristics usable for the genotyping analyses, and those specific features could contribute to the establishment of molecular taxonomy for the species complex of Acanthamoeba. PMID:24039282

  3. Anti-amoebic properties of a Malaysian marine sponge Aaptos sp. on Acanthamoeba castellanii.

    PubMed

    Nakisah, M A; Ida Muryany, M Y; Fatimah, H; Nor Fadilah, R; Zalilawati, M R; Khamsah, S; Habsah, M

    2012-03-01

    Crude methanol extracts of a marine sponge, Aaptos aaptos, collected from three different localities namely Kapas, Perhentian and Redang Islands, Terengganu, Malaysia, were tested in vitro on a pathogenic Acanthamoeba castellanii (IMR isolate) to examine their anti-amoebic potential. The examination of anti-Acanthamoebic activity of the extracts was conducted in 24 well plates for 72 h at 30 °C. All extracts possessed anti-amoebic activity with their IC(50) values ranging from 0.615 to 0.876 mg/mL. The effect of the methanol extracts on the surface morphology of A. castellanii was analysed under scanning electron microscopy. The ability of the extracts to disrupt the amoeba cell membrane was indicated by extensive cell's blebbing, changes in the surface morphology, reduced in cell size and with cystic appearance of extract-treated Acanthamoeba. Number of acanthapodia and food cup was also reduced in this Acanthamoeba. Morphological criteria of apoptosis in Acanthamoeba following treatment with the sponge's extracts was determined by acridine orange-propidium iodide staining and observed by fluorescence microscopy. By this technique, apoptotic and necrotic cells can be visualized and quantified. The genotoxic potential of the methanol extracts was performed by the alkaline comet assay. All methanol extracts used were significantly induced DNA damage compared to untreated Acanthamoeba by having high percentage of scores 1, 2, and 3 of the DNA damage. Results from cytotoxicity and genotoxicity studies carried out in the present study suggest that all methanol extracts of A. aaptos have anti-amoebic properties against A. castellanii. PMID:22805843

  4. Necrotizing Meningoencephalitis in a Captive Black and White Ruffed Lemur (Varecia variegata variegata) Caused by Acanthamoeba T4 Genotype.

    PubMed

    Gaide, N; Pelandakis, M; Robveille, C; Albaric, O; Jouvion, G; Souchon, M; Risler, A; Abadie, J

    2015-11-01

    A mature male, black and white ruffed lemur (Varecia variegata variegata) died in a zoological garden after a 4-day history of lethargy and non-responsive convulsions. Necropsy and histopathological examinations revealed acute necrotizing and haemorrhagic meningoencephalitis with intralesional amoebas confirmed by immunohistochemistry. Acanthamoeba T4 genotype was identified as the causative agent of the brain lesion, based on amplification and sequencing of 18S ribosomal RNA genes. The presence of free-living amoebas in water and mud from the lemur's environment was investigated by morphological and molecular analyses. The two predominant genera, representing 80% of isolated amoebas, were Naegleria spp. and Acanthamoeba spp. All Acanthamoeba isolates belonged to the T4 genotype. To the author's knowledge, this is the first report of a meningoencephalitis due to Acanthamoeba T4 genotype in Lemuridae with concurrent analysis of pathological tissues and environment.

  5. Status of free-living amoebae (Acanthamoeba spp., Naegleria fowleri, Balamuthia mandrillaris) in drinking water supplies in Karachi, Pakistan.

    PubMed

    Yousuf, Farzana Abubakar; Siddiqui, Ruqaiyyah; Subhani, Faysal; Khan, Naveed Ahmed

    2013-06-01

    The ability of pathogenic free-living amoebae to produce infections is a growing concern. In this study, we investigated the presence of free-living amoebae (Acanthamoeba spp., Naegleria fowleri, Balamuthia mandrillaris) in drinking water supplies in Karachi, Pakistan. Fifty-two domestic tap water samples were examined. Amoebae were identified by morphological characteristics and polymerase chain reaction. Thirty percent of the examined samples were positive for Acanthamoeba spp., 8% for N. fowleri while B. mandrillaris were not recovered. Additionally we examined secretory IgA antibody to Acanthamoeba and B. mandrillaris. Acanthamoeba antibody prevalence rate was 100% in both males and females, while B. mandrillaris antibody prevalence rate was 5.5% in males only (females were negative). Our findings suggest that free-living amoebae are a potential health hazard in domestic water supplies in Karachi, Pakistan. PMID:23708583

  6. Acanthamoeba spp. in domestic tap water in houses of contact lens wearers in the metropolitan area of Mexico City.

    PubMed

    Bonilla-Lemus, Patricia; Ramírez-Bautista, Gerardo A; Zamora-Muñoz, Claudia; Ibarra-Montes, María Del Rocío; Ramírez-Flores, Elizabeth; Hernández-Martínez, María Dolores

    2010-09-01

    A survey was carried out in the metropolitan area of Mexico City to determine the presence of Acanthamoeba in the tap water of houses of contact lens wearers. Water samples were taken from the mains water entry, bathroom sinks and storage containers (roof tanks, cisterns) of 27 houses; and from the solution contained in the contact lens cases. Samples were filtered and cultured onto NNE medium. The isolates were identified based on their morphological features and pathogenicity. Total and fecal coliforms, water temperature, pH, dissolved oxygen and residual free-chlorine were measured by standard methods. Forty five isolates of Acanthamoeba from 200 water samples were obtained. The highest number of amoebae was isolated from cisterns and roof tanks. Most Acanthamoeba isolates were non-pathogenic, however, their presence in tap water is a potential hazard since some species can cause Acanthamoeba keratitis and granulomatous amoebic encephalitis. PMID:19995560

  7. Acanthamoeba genotypes T2, T4, and T11 in soil sources from El Hierro island, Canary Islands, Spain.

    PubMed

    Reyes-Batlle, María; Zamora-Herrera, Jonadab; Vargas-Mesa, Alejandro; Valerón-Tejera, Marco Antonio; Wagner, Carolina; Martín-Navarro, Carmen Ma; López-Arencibia, Atteneri; Sifaoui, Ines; Martínez-Carretero, Enrique; Valladares, Basilio; Piñero, José E; Lorenzo-Morales, Jacob

    2016-08-01

    The genus Acanthamoeba includes pathogenic strains which are causative agents of keratitis and encephalitis that often may end fatal in humans and other animals. In the present study, forty soil samples were collected in the island of El Hierro, Canary Islands, Spain, and checked for the presence of Acanthamoeba. Samples were cultivated onto 2 % non-nutrient agar plates seeded with a layer of heat killed Escherichia coli. Amplification by PCR and sequencing of the DF3 region of the 18S rDNA of Acanthamoeba was carried out in order to confirm morphological identification of the amoebae. Furthermore, Acanthamoeba spp. was isolated from 47.5 % of soil samples. Moreover, genotypes T2, T4, and T11 were identified in these samples. To the best of our knowledge, this is the first study to establish genotypes T2, T4, and T11 in soil sources from El Hierro island.

  8. Status of free-living amoebae (Acanthamoeba spp., Naegleria fowleri, Balamuthia mandrillaris) in drinking water supplies in Karachi, Pakistan.

    PubMed

    Yousuf, Farzana Abubakar; Siddiqui, Ruqaiyyah; Subhani, Faysal; Khan, Naveed Ahmed

    2013-06-01

    The ability of pathogenic free-living amoebae to produce infections is a growing concern. In this study, we investigated the presence of free-living amoebae (Acanthamoeba spp., Naegleria fowleri, Balamuthia mandrillaris) in drinking water supplies in Karachi, Pakistan. Fifty-two domestic tap water samples were examined. Amoebae were identified by morphological characteristics and polymerase chain reaction. Thirty percent of the examined samples were positive for Acanthamoeba spp., 8% for N. fowleri while B. mandrillaris were not recovered. Additionally we examined secretory IgA antibody to Acanthamoeba and B. mandrillaris. Acanthamoeba antibody prevalence rate was 100% in both males and females, while B. mandrillaris antibody prevalence rate was 5.5% in males only (females were negative). Our findings suggest that free-living amoebae are a potential health hazard in domestic water supplies in Karachi, Pakistan.

  9. Acanthamoeba spp. in domestic tap water in houses of contact lens wearers in the metropolitan area of Mexico City.

    PubMed

    Bonilla-Lemus, Patricia; Ramírez-Bautista, Gerardo A; Zamora-Muñoz, Claudia; Ibarra-Montes, María Del Rocío; Ramírez-Flores, Elizabeth; Hernández-Martínez, María Dolores

    2010-09-01

    A survey was carried out in the metropolitan area of Mexico City to determine the presence of Acanthamoeba in the tap water of houses of contact lens wearers. Water samples were taken from the mains water entry, bathroom sinks and storage containers (roof tanks, cisterns) of 27 houses; and from the solution contained in the contact lens cases. Samples were filtered and cultured onto NNE medium. The isolates were identified based on their morphological features and pathogenicity. Total and fecal coliforms, water temperature, pH, dissolved oxygen and residual free-chlorine were measured by standard methods. Forty five isolates of Acanthamoeba from 200 water samples were obtained. The highest number of amoebae was isolated from cisterns and roof tanks. Most Acanthamoeba isolates were non-pathogenic, however, their presence in tap water is a potential hazard since some species can cause Acanthamoeba keratitis and granulomatous amoebic encephalitis.

  10. Infection in a rat model reactivates attenuated virulence after long-term axenic culture of Acanthamoeba spp

    PubMed Central

    Veríssimo, Carolina De Marco; Maschio, Vinícius José; Correa, Ana Paula Folmer; Brandelli, Adriano; Rott, Marilise Brittes

    2013-01-01

    Prolonged culturing of many microorganisms leads to the loss of virulence and a reduction of their infective capacity. However, little is known about the changes in the pathogenic strains of Acanthamoeba after long culture periods. Our study evaluated the effect of prolonged culturing on the invasiveness of different isolates of Acanthamoeba in an in vivo rat model. ATCC strains of Acanthamoeba, isolates from the environment and clinical cases were evaluated. The in vivo model was effective in establishing the infection and differentiating the pathogenicity of the isolates and re-isolates. The amoebae cultured in the laboratory for long periods were less virulent than those that were recently isolated, confirming the importance of passing Acanthamoeba strains in animal models. PMID:24271042

  11. Necrotizing Meningoencephalitis in a Captive Black and White Ruffed Lemur (Varecia variegata variegata) Caused by Acanthamoeba T4 Genotype.

    PubMed

    Gaide, N; Pelandakis, M; Robveille, C; Albaric, O; Jouvion, G; Souchon, M; Risler, A; Abadie, J

    2015-11-01

    A mature male, black and white ruffed lemur (Varecia variegata variegata) died in a zoological garden after a 4-day history of lethargy and non-responsive convulsions. Necropsy and histopathological examinations revealed acute necrotizing and haemorrhagic meningoencephalitis with intralesional amoebas confirmed by immunohistochemistry. Acanthamoeba T4 genotype was identified as the causative agent of the brain lesion, based on amplification and sequencing of 18S ribosomal RNA genes. The presence of free-living amoebas in water and mud from the lemur's environment was investigated by morphological and molecular analyses. The two predominant genera, representing 80% of isolated amoebas, were Naegleria spp. and Acanthamoeba spp. All Acanthamoeba isolates belonged to the T4 genotype. To the author's knowledge, this is the first report of a meningoencephalitis due to Acanthamoeba T4 genotype in Lemuridae with concurrent analysis of pathological tissues and environment. PMID:26297109

  12. Evaluation of the orientation of the steepest meridian of regular astigmatism among highly myopic Egyptian patients seeking non-ablative surgical correction of the refractive error

    PubMed Central

    Refai, Tamer Adel

    2015-01-01

    Introduction: LASIK surgery is currently the preferred procedure to correct low to moderate myopia. The aim of this study was to determine the orientation of the steepest meridian of regular astigmatism in order to determine the relative incidence of vertical, horizontal, and oblique regular astigmatism among highly myopic Egyptian patients seeking non-ablative surgical correction of the refractive error. Methods: One hundred and one eyes of 68 highly myopic patients who were seeking refractive surgery were included in this consecutive case series study. The refractive errors were measured using an autorefractometer and confirmed by trial. We measured the uncorrected and best corrected visual acuity in Snellen lines. Keratometry, central corneal thickness, and anterior chamber depth also were measured. The cylinder power in diopters and the axis in degrees were reported. Astigmatism was graded as with the rule (i.e., vertical meridian steeper), against the rule (i.e., horizontal meridian steeper), and oblique astigmatism. The number and the percentage of eyes with the rule, against the rule, and oblique astigmatism were calculated, and the chi-squared test was performed to analyze the data. Results: The spherical refractive error ranged from −6.5 to −24.5 diopters (−13.45 ± 4.60). The cylinder power (Cyl) ranged from −0.25 to −7.5 diopters (−2.23 ± 1.28). The uncorrected visual acuity (UCVA) in Snellen lines ranged from 0.01 – 0.1 (0.03 ± 0.02). The mean for best corrected visual acuity (BCVA) in Snellen lines was 0.40 (± 0.23). The steepest meridian was vertical (i.e., with-the-rule astigmatism) in 44 eyes (43.56%), horizontal (i.e., against-the-rule astigmatism) in 27 eyes (26.73%), and oblique (i.e., oblique astigmatism) in 30 eyes (29.70%). Conclusions: The incidence of with-the-rule astigmatism in patients with high myopia was found to be much lower than in previous studies for non-myopic patients, with a higher incidence for against

  13. Hypoxia attenuates inflammatory mediators production induced by Acanthamoeba via Toll-like receptor 4 signaling in human corneal epithelial cells

    SciTech Connect

    Pan, Hong; Wu, Xinyi

    2012-04-13

    Highlights: Black-Right-Pointing-Pointer Hypoxia attenuates Acanthamoeba-induced the production of IL-8 and IFN-{beta}. Black-Right-Pointing-Pointer Hypoxia inhibits TLR4 expression in a time-dependent manner in HCECs. Black-Right-Pointing-Pointer Hypoxia inhibits Acanthamoeba-induced the activation of NF-{kappa}B and ERK1/2 in HCECs. Black-Right-Pointing-Pointer Hypoxia decreases Acanthamoeba-induced inflammatory response via TLR4 signaling. Black-Right-Pointing-Pointer LPS-induced the secretion of IL-6 and IL-8 is abated by hypoxia via TLR4 signaling. -- Abstract: Acanthamoeba keratitis (AK) is a vision-threatening corneal infection that is intimately associated with contact lens use which leads to hypoxic conditions on the corneal surface. However, the effect of hypoxia on the Acanthamoeba-induced host inflammatory response of corneal epithelial cells has not been studied. In the present study, we investigated the effect of hypoxia on the Acanthamoeba-induced production of inflammatory mediators interleukin-8 (IL-8) and interferon-{beta} (IFN-{beta}) in human corneal epithelial cells and then evaluated its effects on the Toll-like receptor 4 (TLR4) signaling, including TLR4 and myeloid differentiation primary response gene (88) (MyD88) expression as well as the activation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-{kappa}B) and extracellular signal-regulated kinases 1/2 (ERK1/2). We then studied the effect of hypoxia on a TLR4-specific inflammatory response triggered by the TLR4 ligand lipopolysaccharide (LPS). Our data showed that hypoxia significantly decreased the production of IL-8 and IFN-{beta}. Furthermore, hypoxia attenuated Acanthamoeba-triggered TLR4 expression as well as the activation of NF-{kappa}B and ERK1/2, indicating that hypoxia abated Acanthamoeba-induced inflammatory responses by affecting TLR4 signaling. Hypoxia also inhibited LPS-induced IL-6 and IL-8 secretion, myeloid differentiation primary response gene (88

  14. Real-time PCR method for the detection and quantification of Acanthamoeba species in various types of water samples.

    PubMed

    Kao, Po-Min; Tung, Min-Che; Hsu, Bing-Mu; Tsai, Hsien-Lung; She, Cheng-Yu; Shen, Shu-Min; Huang, Wen-Chien

    2013-03-01

    In this study, a quantitative real-time PCR was developed to detect and quantify Acanthamoeba spp. in various environmental water samples. The water samples were taken from watershed, water treatment plant, and three thermal spring recreation areas. The overall detection rate was 14.2 % (25/176) for Acanthamoeba spp. The percentages of samples containing Acanthamoeba spp. from river water, raw drinking water, and thermal spring water were 13 % (13/100), 25 % (7/28), and 10.4 % (5/48), respectively. Acanthamoeba spp. concentrations were determined according to SYBR Green quantitative real-time PCR. A plasmid-based standard curve was constructed to determine the Acanthamoeba concentration using dilution factors for achieving 1.36 × 10(9) gene copies per PCR for 18S rRNA gene in Acanthamoeba spp. The resulting concentrations varied by the type of water, in the range of 46-2.6 × 10(2) cells/l in positive raw drinking water, 2.7 × 10(2)-1.5 × 10(4) cells/l in river water, and 54-1.7 × 10(3) cells/l in thermal spring water. The presence of Acanthamoeba spp. in the raw drinking water samples was also found to have a significant difference with heterotrophic plate count. The presence of Acanthamoeba spp. in various aquatic environments may be a potential health hazard and must be further evaluated.

  15. Three-dimensional localization precision of the double-helix point spread function versus astigmatism and biplane

    NASA Astrophysics Data System (ADS)

    Badieirostami, Majid; Lew, Matthew D.; Thompson, Michael A.; Moerner, W. E.

    2010-10-01

    Wide-field microscopy with a double-helix point spread function (DH-PSF) provides three-dimensional (3D) position information beyond the optical diffraction limit. We compare the theoretical localization precision for an unbiased estimator of the DH-PSF to that for 3D localization by astigmatic and biplane imaging using Fisher information analysis including pixelation and varying levels of background. The DH-PSF results in almost constant localization precision in all three dimensions for a 2 μm thick depth of field while astigmatism and biplane improve the axial localization precision over smaller axial ranges. For high signal-to-background ratio, the DH-PSF on average achieves better localization precision.

  16. Three-dimensional localization precision of the double-helix point spread function versus astigmatism and biplane.

    PubMed

    Badieirostami, Majid; Lew, Matthew D; Thompson, Michael A; Moerner, W E

    2010-10-18

    Wide-field microscopy with a double-helix point spread function (DH-PSF) provides three-dimensional (3D) position information beyond the optical diffraction limit. We compare the theoretical localization precision for an unbiased estimator of the DH-PSF to that for 3D localization by astigmatic and biplane imaging using Fisher information analysis including pixelation and varying levels of background. The DH-PSF results in almost constant localization precision in all three dimensions for a 2 μm thick depth of field while astigmatism and biplane improve the axial localization precision over smaller axial ranges. For high signal-to-background ratio, the DH-PSF on average achieves better localization precision.

  17. Photorefractive keratectomy with mitomycin-C for the treatment of compound moderate myopia with astigmatism in buccal pemphigus vulgaris.

    PubMed

    Taheri, Seyed Mohammad Reza; Kheiltash, Azita

    2007-10-01

    We report a case of controlled buccal pemphigus vulgaris with compound moderate myopia with astigmatism that was treated with photorefractive keratectomy with mitomycin-C (PRK+MMC) in both eyes. The preoperative manifest refraction was -6.50 sphere and -5.5 -0.75 x 20 in the right eye and left eye, respectively, with a best corrected visual acuity of 10/10 in both eyes. Seven months after surgery, the uncorrected visual acuity was 10/10 in both eyes. The manifest refraction was 0.75 sphere and 0.50 -0.75 x 120 in the right eye and left eye, respectively. Haze was not detected in the follow-up examinations. Reepithelialization was complete 5 days after surgery in both eyes. The results show that PRK+MMC for compound moderate myopia with astigmatism in a patient with controlled pemphigus vulgaris may be an effective and safe treatment.

  18. Apparatus for and method of correcting for astigmatism in a light beam reflected off of a light reflecting surface

    DOEpatents

    Sawicki, Richard H.; Sweatt, William

    1987-01-01

    A technique for adjustably correcting for astigmatism in a light beam is disclosed herein. This technique utilizes first means which defines a flat, rectangular light reflecting surface having opposite reinforced side edges and which is resiliently bendable, to a limited extent, into different concave and/or convex cylindrical curvatures about a particular axis and second means acting on the first means for adjustably bending the light reflecting surface into a particular selected one of the different curvatures depending upon the astigmatism to be corrected for and for fixedly maintaining the curvature selected. In the embodiment disclosed, the light reflecting surface is adjustably bendable into the selected cylindrical curvature by application of a particular bending moment to the reinforced side edges of the light reflecting surface.

  19. Orbital angular moment of a partially coherent beam propagating through an astigmatic ABCD optical system with loss or gain.

    PubMed

    Cai, Yangjian; Zhu, Shijun

    2014-04-01

    We derive the general expression for the orbital angular momentum (OAM) flux of an astigmatic partially coherent beam carrying twist phase [i.e., twisted anisotropic Gaussian-Schell model (TAGSM) beam] propagating through an astigmatic ABCD optical system with loss or gain. The evolution properties of the OAM flux of a TAGSM beam in a Gaussian cavity or propagating through a cylindrical thin lens are illustrated numerically with the help of the derived formula. It is found that we can modulate the OAM of a partially coherent beam by varying the parameters of the cavity or the orientation angle of the cylindrical thin lens, which will be useful in some applications, such as free-space optical communications and particle trapping.

  20. Acanthamoeba infection in lungs of mice expressed by toll-like receptors (TLR2 and TLR4).

    PubMed

    Derda, Monika; Wojtkowiak-Giera, Agnieszka; Kolasa-Wołosiuk, Agnieszka; Kosik-Bogacka, Danuta; Hadaś, Edward; Jagodziński, Paweł P; Wandurska-Nowak, Elżbieta

    2016-06-01

    Toll-like receptors (TLRs) play a key role in the innate immune responses to a variety of pathogens including parasites. TLRs are among the most highly conserved in the evolution of the receptor family, localized mainly on cells of the immune system and on other cells such as lung cells. The aim of this study was to determine for the first time the expression of TLR2 and TLR4 in the lung of Acanthamoeba spp. infected mice using quantitative real-time polymerase chain reaction (Q-PCR) and immunohistochemical (IHC) staining. The Acanthamoeba spp. were isolated from a patient with Acanthamoeba keratitis (AK) (strain Ac 55) and from environmental samples of water from Malta Lake (Poznań, Poland - strain Ac 43). We observed a significantly increased level of expression of TLR2 as well as TLR4 mRNA from 2 to 30 days post Acanthamoeba infection (dpi) in the lungs of mice infected with Ac55 (KP120880) and Ac43 (KP120879) strains. According to our observations, increased TLR2 and TLR4 expression in the pneumocytes, interstitial cells and epithelial cells of the bronchial tree may suggest an important role of these receptors in protective immunity against Acanthamoeba infection in the lung. Moreover, increased levels of TLR2 and TLR4 mRNA expression in infected Acanthamoeba mice may suggest the involvement of these TLRs in the recognition of this amoeba pathogen-associated molecular pattern (PAMP). PMID:26940205

  1. Acanthamoeba infection in lungs of mice expressed by toll-like receptors (TLR2 and TLR4).

    PubMed

    Derda, Monika; Wojtkowiak-Giera, Agnieszka; Kolasa-Wołosiuk, Agnieszka; Kosik-Bogacka, Danuta; Hadaś, Edward; Jagodziński, Paweł P; Wandurska-Nowak, Elżbieta

    2016-06-01

    Toll-like receptors (TLRs) play a key role in the innate immune responses to a variety of pathogens including parasites. TLRs are among the most highly conserved in the evolution of the receptor family, localized mainly on cells of the immune system and on other cells such as lung cells. The aim of this study was to determine for the first time the expression of TLR2 and TLR4 in the lung of Acanthamoeba spp. infected mice using quantitative real-time polymerase chain reaction (Q-PCR) and immunohistochemical (IHC) staining. The Acanthamoeba spp. were isolated from a patient with Acanthamoeba keratitis (AK) (strain Ac 55) and from environmental samples of water from Malta Lake (Poznań, Poland - strain Ac 43). We observed a significantly increased level of expression of TLR2 as well as TLR4 mRNA from 2 to 30 days post Acanthamoeba infection (dpi) in the lungs of mice infected with Ac55 (KP120880) and Ac43 (KP120879) strains. According to our observations, increased TLR2 and TLR4 expression in the pneumocytes, interstitial cells and epithelial cells of the bronchial tree may suggest an important role of these receptors in protective immunity against Acanthamoeba infection in the lung. Moreover, increased levels of TLR2 and TLR4 mRNA expression in infected Acanthamoeba mice may suggest the involvement of these TLRs in the recognition of this amoeba pathogen-associated molecular pattern (PAMP).

  2. Isolation and molecular characterization of Acanthamoeba genotypes in recreational and domestic water sources from Jamaica, West Indies.

    PubMed

    Todd, Cheridah D; Reyes-Batlle, María; Piñero, José E; Martínez-Carretero, Enrique; Valladares, Basilio; Streete, Don; Lorenzo-Morales, Jacob; Lindo, John F

    2015-09-01

    Free living amoebae (FLA) are amphizoic protozoa that are ubiquitous in nature. Infection with FLA may result in neurological, ocular and skin infections. Exposure to Acanthamoeba occurs frequently through water contact and knowledge of the presence of the organisms in water sources is important in understanding transmission dynamics. The distribution of Acanthamoeba was studied in recreational and domestic water samples collected from across Jamaica. Morphological assessment and polymerase chain reaction revealed Acanthamoeba spp. isolates in 50.6% (42/83) and 17.3% (14/81) of recreational and domestic water, respectively. Sequencing of the DF3 region of the 18S rDNA resulted in the identification of genotypes T3, T4, T5, T10 and T11 corresponding to Acanthamoeba spp: A. griffini, A. triangularis, A. lenticulata, A. culbertsoni and A. hatchetti. Moreover, T4 was the most frequently isolated genotype in both recreational and domestic water. Thermotolerance and osmotolerance assays indicated that most isolates were potentially pathogenic. This is the first report of T3 and T10 genotypes in the Caribbean and the first report of these Acanthamoeba spp. in Jamaican waters. The study shows that there is potential risk of infection to contact wearers who practise poor lens care. Further, Acanthamoeba should be considered as a cause of neurological infections in Jamaica.

  3. Isolation and genotyping of free-living environmental isolates of Acanthamoeba spp. from bromeliads in Southern Brazil.

    PubMed

    Landell, Melissa Fontes; Salton, Juliana; Caumo, Karin; Broetto, Leonardo; Rott, Marilise B

    2013-07-01

    Species of Acanthamoeba are frequently isolated from distinct environmental sources such as water, soil, dust and air. They are responsible to cause infections and disease in humans and animals. In addition, Acanthamoeba sp. are considered an important reservoir of bacteria, virus and fungi, which act as "Trojan horses" to protect these microorganisms of harsh environmental conditions. In this study, nine Acanthamoeba isolates from bromeliads phylloplane were identified based on the morphology of cyst and trophozoite forms. The genotype level was accessed by the sequence analysis of Acanthamoeba small-subunit rRNA gene. Genotypic characterization grouped five isolates in the genotype T2/T6, three in the T4 genotype and one in the genotype T16. The results obtained indicate that the genotype T2/T6 is common on phylloplane. To predict the pathogenic potential of the Acanthamoeba isolates, thermo and osmotolerance assays were employed, although all isolates were capable of surviving at temperatures of 37°C, other tests will be conducted in the future to determine the potential pathogenic of the isolates. Altogether, our results revealed the importance of the presence of Acanthamoeba associated with bromeliads in Rio Grande do Sul, Brazil, and the necessity for further studies to determine the environmental distribution and the role of these species. PMID:23562883

  4. Management of moderate and severe corneal astigmatism with AcrySof® toric intraocular lens implantation – Our experience

    PubMed Central

    Farooqui, Javed Hussain; Koul, Archana; Dutta, Ranjan; Shroff, Noshir Minoo

    2015-01-01

    Purpose Visual performance following toric intraocular lens implantation for cataract with moderate and severe astigmatism. Setting Cataract services, Shroff Eye Centre, New Delhi, India. Design Case series. Method This prospective study included 64 eyes of 40 patients with more than 1.50 dioptre (D) of pre-existing corneal astigmatism undergoing phacoemulsification with implantation of the AcrySof® toric IntraOcular Lens (IOL). The unaided visual acuity (UCVA), best corrected visual acuity (BCVA), residual refractive sphere and refractive cylinders were evaluated. Toric IOL axis and alignment error was measured by slit lamp method and Adobe Photoshop (version 7) method. Patient satisfaction was evaluated using a satisfaction questionnaire at 3 months. Results The mean residual refractive astigmatism was 0.57 D at the final follow-up of 3 months. Mean alignment error was 3.44 degrees (SD = 2.60) by slit lamp method and 3.88 degrees (SD = 2.86) by Photoshop method. Forty-six (71.9%) eyes showed misalignment of 5 degrees or less, and 60 (93.8%) eyes showed misalignment of 10 degrees or less. The mean log MAR UCVA at 1st post-op day was 0.172 (SD = 0.02), on 7th post-op day was 0.138 (SD = 0.11), and on 30th post-op day was 0.081 (SD = 0.11). The mean log MAR BCVA at three months was −0.04 (SD = 0.76). Conclusion We believe that implantation of AcrySof® toric IOL is an effective, safe and predictable method to correct high amounts of corneal astigmatism during cataract surgery. PMID:26586976

  5. Stability and astigmatic compensation analysis of five- and six- or seven-mirror cavities for mode-locked dye lasers

    SciTech Connect

    Cojocaru, E.; Julea, T.; Herisanu, N.

    1989-07-01

    An analysis of the stability and astigmatic compensation of five- and six- or seven-mirror cavities for mode-locked dye lasers and simple relations for the folding angle to get a maximum stability region are given in this paper. Analytical relations referring to equivalent resonators are deduced. We draw attention to the lack of opportunity to use long cavity approximation to obtain stability diagrams and made some considerations on beam waist sizes.

  6. Non-astigmatic imaging with matched pairs of spherically bent reflectors

    DOEpatents

    Bitter, Manfred Ludwig; Hill, Kenneth Wayne; Scott, Steven Douglas; Feder, Russell; Ko, Jinseok; Rice, John E.; Ince-Cushman, Alexander Charles; Jones, Frank

    2012-07-10

    Arrangements for the point-to-point imaging of a broad spectrum of electromagnetic radiation and ultrasound at large angles of incidence employ matched pairs of spherically bent reflectors to eliminate astigmatic imaging errors. Matched pairs of spherically bent crystals or spherically bent multi-layers are used for X-rays and EUV radiation; and matched pairs of spherically bent mirrors that are appropriate for the type of radiation are used with microwaves, infrared and visible light, or ultrasound. The arrangements encompass the two cases, where the Bragg angle--the complement to the angle of incidence in optics--is between 45.degree. and 90.degree. on both crystals/mirrors or between 0.degree. and 45.degree. on the first crystal/mirror and between 45.degree. and 90.degree. on the second crystal/mirror, where the angles of convergence and divergence are equal. For x-rays and EUV radiation, also the Bragg condition is satisfied on both spherically bent crystals/multi-layers.

  7. Inspection focus technology of space tridimensional mapping camera based on astigmatic method

    NASA Astrophysics Data System (ADS)

    Wang, Zhi; Zhang, Liping

    2010-10-01

    The CCD plane of the space tridimensional mapping camera will be deviated from the focal plane(including the CCD plane deviated due to camera focal length changed), under the condition of space environment and vibration, impact when satellite is launching, image resolution ratio will be descended because defocusing. For tridimensional mapping camera, principal point position and focal length variation of the camera affect positioning accuracy of ground target, conventional solution is under the condition of vacuum and focusing range, calibrate the position of CCD plane with code of photoelectric encoder, when the camera defocusing in orbit, the magnitude and direction of defocusing amount are obtained by photoelectric encoder, then the focusing mechanism driven by step motor to compensate defocusing amount of the CCD plane. For tridimensional mapping camera, under the condition of space environment and vibration, impact when satellite is launching, if the camera focal length changes, above focusing method has been meaningless. Thus, the measuring and focusing method was put forward based on astigmation, a quadrant detector was adopted to measure the astigmation caused by the deviation of the CCD plane, refer to calibrated relation between the CCD plane poison and the asrigmation, the deviation vector of the CCD plane can be obtained. This method includes all factors caused deviation of the CCD plane, experimental results show that the focusing resolution of mapping camera focusing mechanism based on astigmatic method can reach 0.25 μm.

  8. Advanced astigmatism-corrected tandem Wadsworth mounting for small-scale spectral broadband imaging spectrometer.

    PubMed

    Lei, Yu; Lin, Guan-yu

    2013-01-01

    Tandem gratings of double-dispersion mount make it possible to design an imaging spectrometer for the weak light observation with high spatial resolution, high spectral resolution, and high optical transmission efficiency. The traditional tandem Wadsworth mounting is originally designed to match the coaxial telescope and large-scale imaging spectrometer. When it is used to connect the off-axis telescope such as off-axis parabolic mirror, it presents lower imaging quality than to connect the coaxial telescope. It may also introduce interference among the detector and the optical elements as it is applied to the short focal length and small-scale spectrometer in a close volume by satellite. An advanced tandem Wadsworth mounting has been investigated to deal with the situation. The Wadsworth astigmatism-corrected mounting condition for which is expressed as the distance between the second concave grating and the imaging plane is calculated. Then the optimum arrangement for the first plane grating and the second concave grating, which make the anterior Wadsworth condition fulfilling each wavelength, is analyzed by the geometric and first order differential calculation. These two arrangements comprise the advanced Wadsworth mounting condition. The spectral resolution has also been calculated by these conditions. An example designed by the optimum theory proves that the advanced tandem Wadsworth mounting performs excellently in spectral broadband. PMID:23292378

  9. Mild myopic astigmatism corrected by accidental flap complication: a case report.

    PubMed

    Fahed, Daoud C; Fahed, Charbel D

    2009-10-01

    A 35-year-old female presented for laser in-situ keratomileusis (LASIK). Her preoperative eye exam was normal, with a preop refraction of OD -2.50 D Sph +1.25 D Cyl x175 and OS -2.75 D Sph +1.50 D Cyl x165 (cycloplegic and manifest), with 20/20 BCVA OU. The central pachymetry reading was 553 mum in the right eye. Preoperative topography was normal. At the start of the pendular microkeratome path, some resistance was felt, but the microkeratome continued along its path. Upon inspection of the flap, there was a central rectangle of intact epithelium with two mirror-image flaps on both sides. The flap was repositioned and LASIK was discontinued. The cornea healed with two faint thin linear vertical parallel scars at the edge of the pupil. Postoperative inspection of the blade revealed central blunting. One month postoperatively, the uncorrected visual acuity (UCVA) was 20/20. Manifest and cycloplegic refractions were plano. This is an interesting case of accidental flap complication resulting in the correction of mild myopic astigmatism.

  10. Acanthamoeba misidentification and multiple labels: redefining genotypes T16, T19, and T20 and proposal for Acanthamoeba micheli sp. nov. (genotype T19).

    PubMed

    Corsaro, Daniele; Walochnik, Julia; Köhsler, Martina; Rott, Marilise B

    2015-07-01

    Acanthamoeba species are ubiquitous amoebae able to cause important infections in humans and other vertebrates. The full/near-full sequences (>2000 bp) of the small subunit ribosomal RNA gene (SSU rDNA or 18S rDNA) are used to cluster Acanthamoeba as genotypes, labeled T1 to T20. Genotype T15 remains an exception, being described only partially on a 1500-bp fragment. Strains are thus usually identified based on their 18S identity matches with reference strains, often using shorter (<500 bp) diagnostic fragments of the gene. Nevertheless, short fragments (<1000 bp) have been used to propose genotypes. This has been criticized, and doubts arise therefore on possible confusion leading to classify distinct partial sequences with a same label(s). We demonstrate herein that several partial sequences misassigned either to T16 or to T4, actually belong to at least two separate and distinct genotypes. We obtained the full 18S rDNA of a strain previously typed as T16 on the basis of a small fragment and demonstrated that it actually belongs to the recently described T19. We propose the name Acanthamoeba micheli sp. nov., for this strain. Furthermore, partial molecular phylogenies were performed to show that several other misassigned T16 partial sequences belong to a new genotype. This latter includes also misassigned T4 partial sequences, only recently available as full sequences and labeled as T20. We thus reassign these partial sequences to the genotype T20. Longer sequences, ideally at least 90 % of the total gene length, should be obtained from strains to ensure reliable diagnostic and phylogenetic results.

  11. Comparison of Fluorescence Microscopy and Different Growth Media Culture Methods for Acanthamoeba Keratitis Diagnosis

    PubMed Central

    Peretz, Avi; Geffen, Yuval; Socea, Soergiu D.; Pastukh, Nina; Graffi, Shmuel

    2015-01-01

    Acanthamoeba keratitis (AK), a potentially blinding infection of the cornea, is caused by a free-living protozoan. Culture and microscopic examination of corneal scraping tissue material is the conventional method for identifying Acanthamoeba. In this article, we compared several methods for AK diagnosis of 32 patients: microscopic examination using fluorescent dye, specific culture on growth media—non-nutrient agar (NNA), culture on liquid growth media—peptone yeast glucose (PYG), and TYI-S-33. AK was found in 14 patients. Thirteen of the specimens were found AK positive by fluorescence microscopic examination, 11 specimens were found AK positive on PYG growth media, and 9 specimens were found AK positive on TYI-S-33 growth media. Only five specimens were found AK positive on NNA growth media. Therefore, we recommend using fluorescence microscopy technique and culture method, especially PYG liquid media. PMID:25962772

  12. Distribution of Acanthamoeba Genotypes Isolated from Recreational and Therapeutic Geothermal Water Sources in Southwestern Iran

    PubMed Central

    Niyyati, Maryam; Saberi, Reza; Latifi, Alireza; Lasjerdi, Zohreh

    2016-01-01

    A comprehensive survey was conducted along 10 km of geothermal rivers in southwestern Iran. A total of 40 water samples were tested for the presence of Acanthamoeba spp., and genotypes were determined by targeting the diagnostic fragment 3 region of the 18S rRNA gene. The pathogenic potential of all positive isolates was also identified using tolerance ability test. High occurrences of Acanthamoeba (50%) were detected in the sampling areas. Based on sequencing analysis, isolates belonging to T4 (93.7%) and T2 (6.25%) genotypes were reported. Thermo- and osmotolerance tests revealed that five strains are highly pathogenic. Since every collection site of this study was associated with high human activity, posting of warning signs, monitoring of recreational water sources, and awareness of high-risk people are of utmost importance. To the best of our knowledge, the present research is the first to report T2 genotype from geothermal water sources in Iran. PMID:27127409

  13. Superdiffusion dominates intracellular particle motion in the supercrowded cytoplasm of pathogenic Acanthamoeba castellanii

    NASA Astrophysics Data System (ADS)

    Reverey, Julia F.; Jeon, Jae-Hyung; Bao, Han; Leippe, Matthias; Metzler, Ralf; Selhuber-Unkel, Christine

    2015-06-01

    Acanthamoebae are free-living protists and human pathogens, whose cellular functions and pathogenicity strongly depend on the transport of intracellular vesicles and granules through the cytosol. Using high-speed live cell imaging in combination with single-particle tracking analysis, we show here that the motion of endogenous intracellular particles in the size range from a few hundred nanometers to several micrometers in Acanthamoeba castellanii is strongly superdiffusive and influenced by cell locomotion, cytoskeletal elements, and myosin II. We demonstrate that cell locomotion significantly contributes to intracellular particle motion, but is clearly not the only origin of superdiffusivity. By analyzing the contribution of microtubules, actin, and myosin II motors we show that myosin II is a major driving force of intracellular motion in A. castellanii. The cytoplasm of A. castellanii is supercrowded with intracellular vesicles and granules, such that significant intracellular motion can only be achieved by actively driven motion, while purely thermally driven diffusion is negligible.

  14. Comparison of Fluorescence Microscopy and Different Growth Media Culture Methods for Acanthamoeba Keratitis Diagnosis.

    PubMed

    Peretz, Avi; Geffen, Yuval; Socea, Soergiu D; Pastukh, Nina; Graffi, Shmuel

    2015-08-01

    Acanthamoeba keratitis (AK), a potentially blinding infection of the cornea, is caused by a free-living protozoan. Culture and microscopic examination of corneal scraping tissue material is the conventional method for identifying Acanthamoeba. In this article, we compared several methods for AK diagnosis of 32 patients: microscopic examination using fluorescent dye, specific culture on growth media-non-nutrient agar (NNA), culture on liquid growth media-peptone yeast glucose (PYG), and TYI-S-33. AK was found in 14 patients. Thirteen of the specimens were found AK positive by fluorescence microscopic examination, 11 specimens were found AK positive on PYG growth media, and 9 specimens were found AK positive on TYI-S-33 growth media. Only five specimens were found AK positive on NNA growth media. Therefore, we recommend using fluorescence microscopy technique and culture method, especially PYG liquid media.

  15. Superdiffusion dominates intracellular particle motion in the supercrowded cytoplasm of pathogenic Acanthamoeba castellanii.

    PubMed

    Reverey, Julia F; Jeon, Jae-Hyung; Bao, Han; Leippe, Matthias; Metzler, Ralf; Selhuber-Unkel, Christine

    2015-01-01

    Acanthamoebae are free-living protists and human pathogens, whose cellular functions and pathogenicity strongly depend on the transport of intracellular vesicles and granules through the cytosol. Using high-speed live cell imaging in combination with single-particle tracking analysis, we show here that the motion of endogenous intracellular particles in the size range from a few hundred nanometers to several micrometers in Acanthamoeba castellanii is strongly superdiffusive and influenced by cell locomotion, cytoskeletal elements, and myosin II. We demonstrate that cell locomotion significantly contributes to intracellular particle motion, but is clearly not the only origin of superdiffusivity. By analyzing the contribution of microtubules, actin, and myosin II motors we show that myosin II is a major driving force of intracellular motion in A. castellanii. The cytoplasm of A. castellanii is supercrowded with intracellular vesicles and granules, such that significant intracellular motion can only be achieved by actively driven motion, while purely thermally driven diffusion is negligible.

  16. Isolation of Acanthamoeba Genotype T4 from a Non-Contact Lens Wearer from the Philippines

    PubMed Central

    Buerano, Corazon C.; Trinidad, Abigail D.; Fajardo, Lindsay Sydney N.; Cua, Irwin Y.; Baclig, Michael O.; Natividad, Filipinas F.

    2014-01-01

    We report the case of a 76-year old Filipino male who presented with pain, redness, and blurring of vision of the right eye. Corneal scraping was done and sent to the St. Luke’s Research and Biotechnology Group for detection and identification of the infectious agent. Morphological detection was performed by allowing the organism from the scraping to grow in 1.5% non-nutrient agar plate with heat-killed E. coli. Trophozoites with acanthopodia and double-walled cysts characteristic of Acanthamoeba were observed within the first and second week of observations, respectively. Molecular identification of the amoebae at the genus level based on the presence of Acanthamoeba-specific amplimer S1, ASA.S1 confirmed the morphological identification. Genotyping through sequence revealed that the organism belonged to T4, which is the genotype commonly present in the eye of keratitis patients. PMID:25589879

  17. Distribution of Acanthamoeba Genotypes Isolated from Recreational and Therapeutic Geothermal Water Sources in Southwestern Iran.

    PubMed

    Niyyati, Maryam; Saberi, Reza; Latifi, Alireza; Lasjerdi, Zohreh

    2016-01-01

    A comprehensive survey was conducted along 10 km of geothermal rivers in southwestern Iran. A total of 40 water samples were tested for the presence of Acanthamoeba spp., and genotypes were determined by targeting the diagnostic fragment 3 region of the 18S rRNA gene. The pathogenic potential of all positive isolates was also identified using tolerance ability test. High occurrences of Acanthamoeba (50%) were detected in the sampling areas. Based on sequencing analysis, isolates belonging to T4 (93.7%) and T2 (6.25%) genotypes were reported. Thermo- and osmotolerance tests revealed that five strains are highly pathogenic. Since every collection site of this study was associated with high human activity, posting of warning signs, monitoring of recreational water sources, and awareness of high-risk people are of utmost importance. To the best of our knowledge, the present research is the first to report T2 genotype from geothermal water sources in Iran.

  18. Assessment of the efficacy of benzalkonium chloride and sodium hypochlorite against Acanthamoeba polyphaga and Tetrahymena spp.

    PubMed

    Vaerewijck, M J M; Sabbe, K; Baré, J; Spengler, H-P; Favoreel, H W; Houf, K

    2012-03-01

    The efficacy of benzalkonium chloride and sodium hypochlorite against Acanthamoeba polyphaga and two Tetrahymena spp. was determined based on the European Standard EN 1276:2009 suspension test. Trophozoite viability was assessed by determination of the membrane integrity using flow cytometry as a fast screening technique. Bovine serum albumin was added to simulate clean (0.3 g/liter) and dirty (3 g/liter) conditions. Benzalkonium chloride caused cell lysis at concentrations above 50 mg/liter under clean and dirty conditions. A concentration of 50 mg of free chlorine per liter had a strong biocidal effect on acanthamoebae and tetrahymenae after 15 min under clean and dirty conditions. Our results suggest that benzalkonium chloride and sodium hypochlorite were effective against the three microorganisms at concentrations commonly applied in the food industry. PMID:22410229

  19. Comparison of Toric Foldable Iris-Fixated Phakic Intraocular Lens Implantation and Limbal Relaxing Incisions for Moderate-to-High Myopic Astigmatism

    PubMed Central

    Lee, Jeihoon; Lee, Hun; Kang, David Sung Yong; Choi, Jin Young; Kim, Eung Kweon

    2016-01-01

    Purpose To compare the effectiveness of toric foldable iris-fixated phakic intraocular lens (pIOL) implantation and non-toric foldable iris-fixated pIOL implantation with limbal relaxing incisions (LRIs) for correcting moderate-to-high astigmatism in myopic eyes. Materials and Methods The medical records of 146 patients (195 eyes) with myopic astigmatism who underwent toric foldable iris-fixated pIOL implantation (toric group; 94 eyes) or non-toric foldable iris-fixated pIOL implantation with concurrent LRIs (LRI group; 101 eyes) were retrospectively reviewed. For subgroup analysis, the two groups were subdivided according to preoperative astigmatic severity [moderate, 2.00 to <3.00 diopters (D); high, 3.00–4.00 D]. Visual and astigmatic outcomes were compared 6 months postoperatively. Results The uncorrected distance visual acuity was at least 20/25 in 100% and 98% of the toric and LRI group eyes, respectively. The toric group had lower mean residual cylindrical error (-0.67±0.39 D vs. -1.14±0.56 D; p<0.001) and greater mean cylindrical error change (2.17±0.56 D vs. 1.63±0.72 D; p<0.001) than the LRI group, regardless of the preoperative astigmatic severity. The mean correction index (1.10±0.16 vs. 0.72±0.24; p<0.001) and success index (0.24±0.14 vs. 0.42±0.21; p<0.001) also differed significantly between the groups. Conclusion Both surgical techniques considerably reduced astigmatism and had comparable visual outcomes. However, toric foldable iris-fixated pIOL implantation was more reliable for correcting moderate-to-high astigmatism in myopic eyes. PMID:27593877

  20. Effect of Parachlamydia acanthamoebae on pulmonary function parameters in a bovine respiratory model.

    PubMed

    Lohr, M; Prohl, A; Ostermann, C; Diller, R; Greub, G; Reinhold, P

    2016-07-01

    The aim of this study was to evaluate pulmonary dysfunction induced by experimental infection with Parachlamydia acanthamoebae in calves. Intrabronchial inoculation with P. acanthamoebae was performed in 31 calves aged 2-3 months old at two different challenge doses of 10(8) and 10(10) inclusion-forming units (IFU) per animal. Control animals received heat inactivated bacteria. The effects on pulmonary gas exchange were determined by arterial blood gas analysis and haemoximetry during the 7 days post inoculation (DPI). For pulmonary function testing (PFT), impulse oscillometry, capnography, and measurement of O2 uptake were undertaken in spontaneously breathing animals 7 and 3 days before inoculation and were repeated until 10 DPI. In the early phase after challenge (1-3 DPI), mild hypoxaemia occurred, which was accompanied by a significant reduction in both tidal and alveolar volumes (each related to bodyweight, BW). In parallel, expiratory flow rate and specific ventilation (i.e. minute ventilation related to O2 uptake) were significantly increased. Minute and alveolar ventilations (each related to metabolic BW) increased significantly due to higher respiratory rates, lasting until 4 and 5 DPI, respectively. Oxygen uptake was slightly reduced during the first 2 days after challenge, but increased significantly during the recovery phase, from 4 to 8 DPI. No deterioration in respiratory mechanics or acid-base balance was observed. Respiratory infection with 10(10) IFU P. acanthamoebae per calf induced mild respiratory dysfunction, mainly characterised by hypoxaemia. The study's findings do not indicate severe pathophysiological consequences of P. acanthamoebae infection on pulmonary function in the bovine host. PMID:27240907

  1. Survival and transfer ability of phylogenetically diverse bacterial endosymbionts in environmental Acanthamoeba isolates.

    PubMed

    Matsuo, Junji; Kawaguchi, Kouhei; Nakamura, Shinji; Hayashi, Yasuhiro; Yoshida, Mitsutaka; Takahashi, Kaori; Mizutani, Yoshihiko; Yao, Takashi; Yamaguchi, Hiroyuki

    2010-08-01

    Obligate intracellular bacteria are commonly found as endosymbionts of acanthamoebae; however, their survival in and ability to transfer to amoebae are currently uncharacterized. In this study, six bacterial endosymbionts, found in five environmental Acanthamoeba isolates (S13, R18, S23, S31, S40) from different locations of Sapporo city, Japan, were characterized. Phylogenetic analysis revealed that three bacterial endosymbionts (eS23, eS31, eS40a) belonged to α- and β-Proteobacteria phyla and the remaining endosymbionts (eS13, eR18, eS40b) belonged to the order Chlamydiales. The Acanthamoeba isolate (S40) contained two phylogenetically different bacterial endosymbionts (eS40a, eS40b). Fluorescent in situ hybridization analysis showed that all bacterial endosymbionts were diffusely localized within amoebae. Transmission electron microscopy also showed that the endosymbionts were rod-shaped (eS23, eS31, eS40a) or sphere- or crescent-shaped (eS13, eR18, eS40b). No successful culture of these bacteria was achieved using conventional culture methods, but the viability of endosymbionts was confirmed by live/dead staining and RT-PCR methods. However, endosymbionts (except eR18) derived from original host cells lost the ability to be transferred to another Acanthamoebae strains [ATCC strain (C3), environmental strains (S14, R23, S24)]. Thus, our data demonstrate that phylogenetically diverse bacterial endosymbionts found in amoebae maintain a stable interaction with amoebae, but the transferability is limited.

  2. Identification and properties of proteases from an Acanthamoeba isolate capable of producing granulomatous encephalitis

    PubMed Central

    Sissons, James; Alsam, Selwa; Goldsworthy, Graham; Lightfoot, Mary; Jarroll, Edward L; Khan, Naveed Ahmed

    2006-01-01

    Background Granulomatous amoebic encephalitis due to Acanthamoeba is often a fatal human disease. However, the pathogenesis and pathophysiology of Acanthamoeba encephalitis remain unclear. In this study, the role of extracellular Acanthamoeba proteases in central nervous system pathogenesis and pathophysiology was examined. Results Using an encephalitis isolate belonging to T1 genotype, we observed two major proteases with approximate molecular weights of 150 KD and 130 KD on SDS-PAGE gels using gelatin as substrate. The 130 KD protease was inhibited with phenylmethylsulfonyl fluoride (PMSF) suggesting that it is a serine protease, while the 150 KD protease was inhibited with 1, 10-phenanthroline suggesting that it is a metalloprotease. Both proteases exhibited maximal activity at neutral pH and over a range of temperatures, indicating their physiological relevance. These proteases degrade extracellular matrix (ECM), which provide structural and functional support to the brain tissue, as shown by the degradation of collagen I and III (major components of collagenous ECM), elastin (elastic fibrils of ECM), plasminogen (involved in proteolytic degradation of ECM), as well as casein and haemoglobin. The proteases were purified partially using ion-exchange chromatography and their effects were tested in an in vitro model of the blood-brain barrier using human brain microvascular endothelial cells (HBMEC). Neither the serine nor the metalloprotease exhibited HBMEC cytotoxicity. However, the serine protease exhibited HBMEC monolayer disruptions (trypsin-like) suggesting a role in blood-brain barrier perturbations. Conclusion Overall, these data suggest that Acanthamoeba proteases digest ECM, which may play crucial role(s) in invasion of the brain tissue by amoebae. PMID:16672059

  3. A Rabbit Model of Acanthamoeba Keratitis That Better Reflects the Natural Human Infection.

    PubMed

    Feng, Xianmin; Zheng, Wenyu; Wang, Yuehua; Zhao, Donghai; Jiang, Xiaoming; Lv, Shijie

    2015-08-01

    Acanthamoeba species are ubiquitous, free-living protozoa that can invade the cornea and result in Acanthamoeba keratitis (AK), a painful progressive sight-threatening corneal disease. Disease progression in current animal models is too rapid to mimic AK in humans accurately. This study provides a novel method for establishing AK in rabbits and compared it with the conventional method with regard to pathogenesis and immune response in humans. The New Zealand white rabbits were randomly divided into two experimental groups (Groups A and B). Rabbits in the Group A (n = 14) received intrastromal injections of 1 × 10(4) /100 µL Acanthamoeba healyi trophozoites (conventional AK model). The Group B animals (n = 14) received microinjections of 1 × 10(4) /10 µL A. healyi trophozoites between the corneal epithelium and Bowman's layer, anterior to the corneal stroma (novel AK model). In addition, two rabbits were left untreated as normal controls. AK in the treated rabbits was evaluated clinically, histopathologically, and immunologically for 35 days. AK was successfully established in both the conventional and novel model groups. Compared with the Group A, AK in the Group B displayed an efficient immune response with less severe pathology. Moreover, the self-limiting but chronic nature of the infection in the Group B was strikingly similar to that of AK in humans. The novel animal model for AK described here more closely simulates the pathogenesis and immune response of Acanthamoeba corneal infection in humans than the animal models currently in use.

  4. Fas deficiency in mice with the Balb/c background induces blepharitis with allergic inflammation and hyper-IgE production in conjunction with severe autoimmune disease.

    PubMed

    Takahashi, Suzuka; Futatsugi-Yumikura, Shizue; Fukuoka, Ayumi; Yoshimoto, Tomohiro; Nakanishi, Kenji; Yonehara, Shin

    2013-05-01

    Fas (CD95) is a cell surface death receptor belonging to the tumor necrosis factor receptor superfamily, which mediates apoptosis-inducing signaling when activated by Fas ligand or its agonistic antibody. lpr mice with a loss of apoptosis-inducing function mutation in the Fas gene develop systemic autoimmune disease and lymphadenopathy but not allergic inflammation. In the case of Fas mutations including lpr and knockout (KO), background genes determine the incidence and severity of lymphadenopathy and histopathological manifestation of systemic autoimmunity: MRL-lpr/lpr mice and C57BL/6-lpr/lpr or C57BL/6 Fas KO mice develop severe and minimum disease, respectively. We generated Fas KO mice with the Balb/c background that show severer autoimmune phenotypes than MRL-lpr/lpr mice, such as critical infiltration of mononuclear cells into lung, liver and spleen, elevated serum levels of auto-antibodies and a decreased life span. To our astonishment, Balb/c Fas KO mice spontaneously develop blepharitis with not only autoimmune inflammation with deposition of auto-antibody but also allergic inflammation with infiltration by eosinophils and mast cells and show the capacity to strongly increase serum level of IgE and IgG1 along with their aging. Thus, Fas expression regulates development of not only autoimmune disease but also allergic inflammation.

  5. Anaerobic respiration: In vitro efficacy of Nitazoxanide against mitochondriate Acanthamoeba castellanii of the T4 genotype.

    PubMed

    Aqeel, Yousuf; Siddiqui, Ruqaiyyah; Farooq, Maria; Khan, Naveed Ahmed

    2015-10-01

    Acanthamoeba is an opportunistic protist pathogen that is responsible for serious human and animal infection. Being one of the most frequently isolated protists from the environment, it is likely that it readily encounters microaerophilic environments. For respiration under anaerobic or low oxygen conditions in several amitochondriate protists, decarboxylation of pyruvate is catalyzed by pyruvate ferredoxin oxidoreductase instead of pyruvate dehydrogenase. In support, Nitazoxanide, an inhibitor of pyruvate ferredoxin oxidoreductase, is effective and non-mutagenic clinically against a range of amitochondriate protists, Giardia intestinalis, Entamoeba histolytica and Trichomonas vaginalis. The overall aim of the present study was to determine in vitro efficacy of Nitazoxanide against Acanthamoeba castellanii. At micromolar concentrations, the findings revealed that Nitazoxanide neither affected A. castellanii growth or viability nor amoeba-mediated host cell monolayer damage in vitro or extracellular proteolytic activities. Similarly, microaerophilic conditions alone had no significant effects. In contrast, microaerophilic conditions together with Nitazoxanide showed amoebicidal effects and inhibited A. castellanii-mediated host cell monolayer damage as well as extracellular proteases. Using encystation assays, it was observed that Nitazoxanide inhibited trophozoite transformation into cysts both under aerophilic and microaerophilic conditions. Furthermore, pre-treatment of cysts with Nitazoxanide inhibited A. castellanii excystation. These findings are important in the identification of potential targets that could be useful against parasite-specific respiration as well as to understand the basic biology of the life cycle of Acanthamoeba.

  6. Prevalence of acanthamoeba from tap water in rio grande do Sul, Brazil.

    PubMed

    Winck, Mari Aline Todero; Caumo, Karin; Rott, Marilise Brittes

    2011-11-01

    A total of 136 samples of tap water were collected from state and municipal schools between March and November 2009. The samples were filtered through cellulose nitrate membranes that were seeded at non-nutrient agar 1.5% containing an overlayer of Escherichia coli suspension. Thirty-one (22.79%) tap water samples investigated were found positive for free-living amoebae (FLA). From these, 13 presented as FLA that seems to belong to the genus Acanthamoeba. All samples of FLA were cloned and identified as belonging to the genus Acanthamoeba by the morphology of cysts and trophozoites and by PCR using genus-specific primers that amplify the ASA.S1 region of 18S rDNA gene. Physiological tests of thermotolerance and osmotolerance were used to evaluate the pathogenicity of the isolates. The sequencing analysis by comparing the sequences submitted to GenBank, showed genotype distribution into groups T2, T2/T6, T6, and T4. In tests of thermotolerance and osmotolerance, 50% of the isolates had a low pathogenic potential. The results indicated the presence of Acanthamoeba in tap water in Rio Grande do Sul, Brazil, revealing its importance and the need for more epidemiological studies to determine their distribution in the environment and its pathogenic potential.

  7. Photodynamic inactivation of Acanthamoeba polyphaga with curcuminoids: an in vitro study

    NASA Astrophysics Data System (ADS)

    Corrêa, Thaila Q.; Geralde, Mariana C.; Carvalho, Mariana T.; Bagnato, Vanderlei S.; Kurachi, Cristina; de Souza, Clovis W. O.

    2016-03-01

    Acanthamoeba polyphaga are free-living amoebae that can be considered potentially pathogenic organisms by cause serious human infections, including keratitis and granulomatous amoebic encephalitis that usually results in death. Photodynamic inactivation (PDI) has been used for the biological control of microorganisms and can be promise in the control of Acanthamoeba infections. This study evaluated the in vitro effectiveness of PDI in A. polyphaga using curcuminoids salt as photosensitizer (PS) besides observing morphological changes caused by this PS in this organism, in confocal microscopy. A. polyphaga trophozoites were grown at 37°C in PYG medium for 48 to 72 hours. After, the trophozoites were incubated with PS solution during one hour and the samples were irradiated using light-emitting diodes at 460 nm at light doses 30 and 50 J/cm2. The results revealed reduction of 27.7%, 61.4% and 82.5% at 30 J/cm2 and 75.2%, 85.0% and 95.9% at 50 J/cm2, respectively, at curcuminoid salt concentrations of 500, 1000 and 1500 μg/mL. Through fluorescence images, it was possible to visualize the curcuminoid salt's uptake by the trophozoites. The PS showed toxicity to amoebae, in the dark, but the irradiation in PDI contributed to amoebae death effect. These data suggest that PDI may be an application of therapeutic intervention against Acanthamoeba infections, since it was effective in the inactivation of these amoebae.

  8. The role of actin in the temperature-dependent gelation and contraction of extracts of Acanthamoeba

    PubMed Central

    1976-01-01

    The temperature-dependent assembly and the interaction of Acanthamoeba contractile proteins have been studied in a crude extract. A cold extract of soluble proteins from Acanthamoeba castellanii is prepared by homogenizing the cells in a sucrose-ATP-ethyleneglycol-bis-(beta- aminoethyl ether) N,N'-tetraacetic acid buffer and centrifuging at 136,000 g for 1 h. When this supernate of soluble proteins is warmed to room temperature, it forms a solid gel. Upon standing at room temperature, the gel slowly contracts and squeezes out soluble components. The rates of gelation and contraction are both highly temperature dependent, with activation energies of about 20 kcal per mol. Gel formation is dependent upon the presence of ATP and Mg++. Low concentrations of Ca++ accelerate the contractile phase of this phenomenon. The major protein component of the gel is actin. It is associated with myosin, cofactor, a high molecular weight protein tentatively identfied as actin-binding protein, and several other unidentified proteins. Actin has been purified from these gels and was found to be capable of forming a solid gel when polymerized in the presence of ATP, MgCl3, and KCL. The rate of purified actin polymerication is very temperature dependent and is accelerated by the addition of fragments of muscle actin filaments. These data suggest that Acanthamoeba contractile proteins have a dual role in the cell; they may generate the forces for cellular movements and also act as cytoskeletal elements by controlling the consistency of the cytoplasm. PMID:1030705

  9. Prevalence of Acanthamoeba and superbugs in a clinical setting: coincidence or hyperparasitism?

    PubMed

    Siddiqui, Ruqaiyyah; Sagheer, Mehwish; Khan, Naveed Ahmed

    2013-03-01

    Antibacterial strategies to eradicate superbugs from hospitals/nursing homes have had limited success, suggesting the need for employing innovative preventative measures and better understanding of the prevalence of microbial pathogens in close proximity of susceptible populations. A total of 120 environmental samples were collected from the Aga Khan University hospital. Amoebae were identified using morphological characteristics as well as PCR using genus-specific primers, while bacteria were identified using standard biochemical testing. Out of 120 samples tested, 52 (43.3 %) samples were positive for Acanthamoeba, while all 120 (100 %) samples were positive for bacteria. Following bacterial identification, samples showed mixed bacterial populations. Out of 120 samples, 76 (63.3 %) samples were positive for Bacillus spp., 64 (53.3 %) samples were positive for Corynebacterium spp., 32 (26.6 %) samples were positive for Staphylococcus spp., and 9 (7.5 %) samples were positive for Micrococcus spp. The antibiotic susceptibility showed that all bacterial isolates recovered were multiple drug-resistant. The current findings suggest that Acanthamoeba and bacteria coexist in a clinical environment. Given that Acanthamoeba can harbor bacteria, anti-amoebic approaches may represent a strategy in eradicating "superbugs" from the clinical setting in addition to the current measures.

  10. Expression levels of encystation mediating factors in fresh strain of Acanthamoeba castellanii cyst ESTs.

    PubMed

    Moon, Eun-Kyung; Chung, Dong-Il; Hong, Yeonchul; Kong, Hyun-Hee

    2011-04-01

    The life cycle of Acanthamoeba consists of two stages, trophozoite and cyst. The cyst form is resistant to almost all antibiotics. By long term cultivation, Acanthamoeba severely attenuated the encysting ability. To determine the changing of gene expression by the long term cultivation, especially focusing an encystation mediating factors, this study compared the ESTs of the fresh strain and the old strain, and trophozoite. Comparison of the KOG (euKaryotic Orthologous Groups) analysis relative to trophozoite revealed higher percentages of cyst ESTs related to G (Carbohydrate transport and metabolism), H (Coenzyme transport and metabolism), I (Lipid transport and metabolism), D (Cell cycle control, cell division, chromosome partitioning), T (signal transduction mechanisms), and O (Posttranslational modification, protein turnover, chaperones). In addition to this result, KOG analysis of fresh strain relative to old strain showed higher percentage of cyst ESTs related to metabolism category and T (signal transduction mechanisms) article. ESTs of the fresh strain revealed more various gene profiles compared to the old strain including encystation mediating factors like autophagy related proteins (Z article) and signal transduction proteins (T article). Twenty seven kinds of protein kinase C (PKC) like genes were detected in cyst or trophozoite ESTs and twenty one of them were highly expressed during encystation. The information of the expressed genes during encystation in only the fresh strain will provide new clues to understanding the encystation mechanism of encysting protozoa including Acanthamoeba. PMID:21276446

  11. Necrotizing meningoencephalitis and pneumonitis in a simian immunodeficiency virus-infected rhesus macaque due to Acanthamoeba.

    PubMed

    Westmoreland, S V; Rosen, J; MacKey, J; Romsey, C; Xia, D-L; Visvesvera, G S; Mansfield, K G

    2004-07-01

    Free-living amoebae of the genus Acanthamoeba can cause a fatal disease of the brain in humans called granulomatous amoebic encephalitis. We present a case of meningoencephalitis and pneumonitis in a simian immunodeficiency virus (SIV)-infected rhesus macaque caused by Acanthamoeba sp. The animal became ill 176 days after intravenous inoculation with SIVmac251 after a short history of weight loss and a sudden onset of hind limb paresis and abnormal head movements. Histopathologic examination of hematoxylin and eosin-stained tissues revealed multifocal to coalescing necrotizing neutrophilic meningoencephalitis and pneumonitis. Immunofluorescence and polymerase chain reaction were used to identify the genus of amoeba as Acanthamoeba. Immunohistochemistry of immune cell markers was used to characterize the animal's immune response to the opportunistic amoebic infection with features of both innate and adaptive cell-mediated immunity. Although not previously reported, the potential transmission to humans, either through environmental contamination or contact with an infected animal, makes this disease a threat to laboratory animal care staff and pathologists. PMID:15232140

  12. Acanthamoeba meningoencephalitis in immunocompetent: A case report and review of literature

    PubMed Central

    Khanna, Vinay; Shastri, BA; Anusha, G; Mukhopadhayay, Chiranjay; Khanna, Ruchee

    2014-01-01

    A 30-year-old manual laborer from Karnataka, India presented with intermittent low grade fever and diffuse headache for 1 month. On examination, patient had enlarged supraclavicular and cervical lymph nodes. Patient had positive Kernig's sign and neck stiffness. Motor, sensory and cranial nerve examinations were within the normal limits. Abdominal, cardiovascular and chest examination did not yield any positive findings. Contrast enhanced computed tomography head was normal. Patient was suspected to have extrapulmonary tuberculosis. Patient was started on antitubercular drugs. Diagnostic lumbar puncture was performed. Wet mount and Giemsa smear preparation of cerebrospinal fluid (CSF) showed trophozoites suggestive of Acanthamoeba. CSF was cultured onto non-nutrient agar with an overlay of Escherichia coli. Wet mount made from the culture media yielded cysts and trophozoites of Acanthamoeba spp. Patient was diagnosed with Acanthamoeba meningitis and was started on specific therapy with Rifampicin 600 mg once a day, Cotrimoxazole 960 mg twice-a-day and Fluconazole 400 mg once daily for 2 weeks. Patient had a complete recovery and was discharged from the hospital. PMID:25250233

  13. Seroprevalence of Acanthamoeba Antibodies in Rheumatoid Arthritis Patients by IFAT, Tehran, Iran 2007

    PubMed Central

    Eftekhar, M; Athari, A; Haghighi, A; Mosaffa, N; Shahram, F; Abadi, A

    2010-01-01

    Background This preliminary study was conducted to discriminate the prevalence of Acanthamoeba antibodies in rheumatoid arthritis (RA) patients and healthy controls to analyze the correlation between these two groups. Methods From October 2006 to August 2007 a total of 121 serum samples from RA patients attending the Rheumatolgy Department at Shariati Hospital in Tehran were obtained and stored at -20°C until using by indirect fluorescent-antibody test (IFAT). RA was diagnosed according to the American Collage of Rheumatology classification criteria. The organism used in this study was isolated from various water resources in Tehran, Iran cultured axenically and then went on a PCR assay based on 18S rRNA to identify the genus Acanthomoeba. Indirect immunofluorescence antibody (IFA) staining of serum samples was carried out to detect anti Acanthomoeba antibodies. Results In culture, out of 22 samples, 13(59%) were grown in xenic but only two in axenic medium. PCR amplified a 904bp fragment, specific for Acanthamoeba. Of examined serum samples, Acanthamoeba antibodies were present in 70 (57.8%) and 52 (41.2%), respectively. The highest titer of antibodies (1:320) was detected in one patient with RA. Conclusion Our study supports the hypothesis that some parasitic microorganisms can involve and contribute toward the development of rheumatoid syndromes. PMID:22347233

  14. Evaluation of Acanthamoeba myosin-IC as a potential therapeutic target.

    PubMed

    Martín-Navarro, Carmen M; Lorenzo-Morales, Jacob; López-Arencibia, Atteneri; Reyes-Batlle, María; Piñero, José E; Valladares, Basilio; Maciver, Sutherland K

    2014-01-01

    Members of the genus Acanthamoeba are facultative pathogens of humans, causing a sight-threatening keratitis and a fatal encephalitis. We have targeted myosin-IC by using small interfering RNA (siRNA) silencing as a therapeutic approach, since it is known that the function of this protein is vital for the amoeba. In this work, specific siRNAs against the Acanthamoeba myosin-IC gene were developed. Treated and control amoebae were cultured in growth and encystment media to evaluate the induced effects after myosin-IC gene knockdown, as we have anticipated that cyst formation may be impaired. The effects of myosin-IC gene silencing were inhibition of cyst formation, inhibition of completion of cytokinesis, inhibition of osmoregulation under osmotic stress conditions, and death of the amoebae. The finding that myosin-IC silencing caused incompletion of cytokinesis is in agreement with earlier suggestions that the protein plays a role in cell locomotion, which is necessary to pull daughter cells apart after mitosis in a process known as "traction-mediated cytokinesis". We conclude that myosin-IC is a very promising potential drug target for the development of much-needed antiamoebal drugs and that it should be further exploited for Acanthamoeba therapy. PMID:24468784

  15. Inactivation of Acanthamoeba spp. and Other Ocular Pathogens by Application of Cold Atmospheric Gas Plasma.

    PubMed

    Heaselgrave, Wayne; Shama, Gilbert; Andrew, Peter W; Kong, Michael G

    2016-05-15

    Currently there are estimated to be approximately 3.7 million contact lens wearers in the United Kingdom and 39.2 million in North America. Contact lens wear is a major risk factor for developing an infection of the cornea known as keratitis due to poor lens hygiene practices. While there is an international standard for testing disinfection methods against bacteria and fungi (ISO 14729), no such guidelines exist for the protozoan Acanthamoeba, which causes a potentially blinding keratitis most commonly seen in contact lens wearers, and as a result, many commercially available disinfecting solutions show incomplete disinfection after 6 and 24 h of exposure. Challenge test assays based on international standard ISO 14729 were used to determine the antimicrobial activity of cold atmospheric gas plasma (CAP) against Pseudomonas aeruginosa, Candida albicans, and trophozoites and cysts of Acanthamoeba polyphaga and Acanthamoeba castellanii P. aeruginosa and C. albicans were completely inactivated in 0.5 min and 2 min, respectively, and trophozoites of A. polyphaga and A. castellanii were completely inactivated in 1 min and 2 min, respectively. Furthermore, for the highly resistant cyst stage of both species, complete inactivation was achieved after 4 min of exposure to CAP. This study demonstrates that the CAP technology is highly effective against bacterial, fungal, and protozoan pathogens. The further development of this technology has enormous potential, as this approach is able to deliver the complete inactivation of ocular pathogens in minutes, in contrast to commercial multipurpose disinfecting solutions that require a minimum of 6 h.

  16. Incidence and molecular diversity of Acanthamoeba species isolated from public baths in Hungary.

    PubMed

    Kiss, Csaba; Barna, Zsófia; Vargha, Márta; Török, Júlia Katalin

    2014-07-01

    Hungary has a large number of thermal baths and spa facilities which attract hundreds of thousands of tourists annually. Until recently, however, the free-living amoebae were not of public health concern. Genotyping of Acanthamoeba species, potential agents of keratitis and granulomatous encephalitis, was carried out in 20 Hungarian public baths for the first time to assess the incidence and molecular diversity of the genus in the country. Our results show that 6.7% of the samples were positive for Acanthamoeba. Of these positive samples, 6.5 and 7% was from sterilized and unsterilized pools, respectively. The 18S rRNA gene investigation of the nine Acanthamoeba strains found reveals that seven belong to the hazardous T4 genotype. The remaining two samples were of the T15 type. All the strains kept growing at 36 °C. Our results underline the need to develop a control system for free-living amoebae and supervise the disinfection of Hungarian public baths.

  17. Evaluation of Acanthamoeba Myosin-IC as a Potential Therapeutic Target

    PubMed Central

    Lorenzo-Morales, Jacob; López-Arencibia, Atteneri; Reyes-Batlle, María; Piñero, José E.; Valladares, Basilio; Maciver, Sutherland K.

    2014-01-01

    Members of the genus Acanthamoeba are facultative pathogens of humans, causing a sight-threatening keratitis and a fatal encephalitis. We have targeted myosin-IC by using small interfering RNA (siRNA) silencing as a therapeutic approach, since it is known that the function of this protein is vital for the amoeba. In this work, specific siRNAs against the Acanthamoeba myosin-IC gene were developed. Treated and control amoebae were cultured in growth and encystment media to evaluate the induced effects after myosin-IC gene knockdown, as we have anticipated that cyst formation may be impaired. The effects of myosin-IC gene silencing were inhibition of cyst formation, inhibition of completion of cytokinesis, inhibition of osmoregulation under osmotic stress conditions, and death of the amoebae. The finding that myosin-IC silencing caused incompletion of cytokinesis is in agreement with earlier suggestions that the protein plays a role in cell locomotion, which is necessary to pull daughter cells apart after mitosis in a process known as “traction-mediated cytokinesis”. We conclude that myosin-IC is a very promising potential drug target for the development of much-needed antiamoebal drugs and that it should be further exploited for Acanthamoeba therapy. PMID:24468784

  18. In Vitro Efficacy of Corifungin against Acanthamoeba castellanii Trophozoites and Cysts

    PubMed Central

    Debnath, Anjan; Tunac, Josefino B.; Silva-Olivares, Angélica; Galindo-Gómez, Silvia

    2014-01-01

    Painful blinding keratitis and fatal granulomatous amebic encephalitis are caused by the free-living amebae Acanthamoeba spp. Several prescription eye medications are used to treat Acanthamoeba keratitis, but the infection can be difficult to control because of recurrence of infection. For the treatment of encephalitis, no single drug was found useful, and in spite of the use of a combination of multiple drugs, the mortality rate remains high. Therefore, efficient, novel drugs are urgently needed for the treatment of amebic keratitis and granulomatous amebic encephalitis. In this study, we identified corifungin, a water-soluble polyene macrolide, as amebicidal. In vitro, it was effective against both the trophozoites and the cysts. Transmission electron microscopy of Acanthamoeba castellanii incubated with corifungin showed the presence of swollen mitochondria, electron-dense granules, degeneration of cytoplasm architecture, and loss of nuclear chromatin structure. These changes were followed by lysis of amebae. Corifungin also induced the encystment process of A. castellanii. There were alterations in the cyst cell wall followed by lysis of the cysts. Corifungin is a promising therapeutic option for keratitis and granulomatous amebic encephalitis. PMID:24366747

  19. Effect of Corneal Incision Enlargement on Surgically Induced Astigmatism in Biaxial Microincision Cataract Surgery

    PubMed Central

    Tetikoğlu, Mehmet; Yeter, Celal; Helvacıoğlu, Fırat; Aktaş, Serdar; Sağdık, Hacı Murat; Özcura, Fatih

    2016-01-01

    Objectives: To evaluate surgically induced astigmatism (SIA) in biaxial microincision cataract surgery with enlargement of one corneal incision during intraocular lens implantation (IOL). Materials and Methods: Data from 683 eyes with cataract that underwent biaxial microincision cataract surgery and IOL were retrospectively analyzed. The operated eyes were divided into 4 groups defined by final corneal incision length after IOL implantation. There were 83 eyes with 1.6 mm corneal incisions (group 1) and 200 eyes in each of the 2, 2.4, and 2.8 mm corneal incision groups (groups 2, 3 and 4, respectively). SIA was assessed using preoperative and postoperative keratometric values at one month. Results: The mean magnitude of SIA was 0.83±0.4 D in group 1, 0.93±0.5 D in group 2, 1.03±0.6 D in group 3 and 1.04±0.7 D in group 4. The SIA showed statistically significant differences between the four groups (p=0.05). Pairwise group comparisons revealed significant differences between groups 1 and 3 and groups 1 and 4 (p=0.005). Conclusion: Biaxial microincision cataract surgery with an incision size of 1.6 mm resulted in the least SIA. Enlargement of the corneal incision beyond 2.0 mm during IOL implantation led to significant increases in SIA. We believe that with the development and dissemination of IOLs which can be inserted through small corneal incisions, biaxial microincision cataract surgery will be the best choice to prevent SIA and increase visual acuity. PMID:27800270

  20. Transmissive liquid-crystal device correcting primary coma aberration and astigmatism in laser scanning microscopy

    NASA Astrophysics Data System (ADS)

    Tanabe, Ayano; Hibi, Terumasa; Ipponjima, Sari; Matsumoto, Kenji; Yokoyama, Masafumi; Kurihara, Makoto; Hashimoto, Nobuyuki; Nemoto, Tomomi

    2016-03-01

    Laser scanning microscopy allows 3D cross-sectional imaging inside biospecimens. However, certain aberrations produced can degrade the quality of the resulting images. We previously reported a transmissive liquid-crystal device that could compensate for the predominant spherical aberrations during the observations, particularly in deep regions of the samples. The device, inserted between the objective lens and the microscope revolver, improved the image quality of fixed-mouse-brain slices that were observed using two-photon excitation laser scanning microscopy, which was originally degraded by spherical aberration. In this study, we developed a transmissive device that corrects primary coma aberration and astigmatism, motivated by the fact that these asymmetric aberrations can also often considerably deteriorate image quality, even near the sample surface. The device's performance was evaluated by observing fluorescent beads using single-photon excitation laser scanning microscopy. The fluorescence intensity in the image of the bead under a cover slip tilted in the y-direction was increased by 1.5 times after correction by the device. Furthermore, the y- and z-widths of the imaged bead were reduced to 66% and 65%, respectively. On the other hand, for the imaged bead sucked into a glass capillary in the longitudinal x-direction, correction with the device increased the fluorescence intensity by 2.2 times compared to that of the aberrated image. In addition, the x-, y-, and z-widths of the bead image were reduced to 75%, 53%, and 40%, respectively. Our device successfully corrected several asymmetric aberrations to improve the fluorescent signal and spatial resolution, and might be useful for observing various biospecimens.

  1. High occurrence of Acanthamoeba genotype T4 in soil sources from Bolívar State, Venezuela.

    PubMed

    Wagner, Carolina; Reyes-Batlle, María; Hernán, Aurora; Rojas, Elsy; Pérez, Gladymar; López-Arencibia, Atteneri; Sifaoui, Ines; Martínez-Carretero, Enrique; Piñero, José E; Valladares, Basilio; Lorenzo-Morales, Jacob

    2016-09-01

    Pathogenic strains of Acanthamoeba are causative agents of keratitis and encephalitis that often may end fatal in humans and other animals. In the present study, twenty-seven soil samples were collected in the Bolivar State in Venezuela and checked for the presence of Acanthamoeba. Samples were cultivated onto 2% non-nutrient agar plates seeded with a layer of heat killed E. coli. Amplification by PCR and sequencing of the DF3 region of the 18S rDNA of Acanthamoeba was carried out in order to confirm morphological identification of the amoebae. Furthermore, Acanthamoeba spp. was isolated from 51.8% of soil samples. Sequencing of the DF3 region of the 18S rDNA resulted in the identification of genotype T4 in all samples. To the best of our knowledge, this is the first report of genotype T4 in soil sources from Venezuela. Further studies should be carried out in this State and in the country in order to determine the current occurrence of Acanthamoeba in Venezuelan environments. PMID:27447209

  2. Synthesis, characterization and amoebicidal potential of locally synthesized TiO2 nanoparticles against pathogenic Acanthamoeba trophozoites in vitro.

    PubMed

    Imran, Muhammad; Muazzam, Ambreen Gul; Habib, Amir; Matin, Abdul

    2016-06-01

    Acanthamoeba is an opportunistic protozoan pathogen that plays a pivotal role in the ecosystem. It may cause blinding keratitis and fatal encephalitis involving the central nervous system. Here we synthesized pure and Zn doped TiO2 nanoparticles (~10-30nm) via sol-gel and sol-hydrothermal methods and demonstrated its impact on the biological characteristics of pathogenic Acanthamoeba castellanii. Our results revealed that pure and Zn doped TiO2 nanoparticles synthesized by sol-hydrothermal methods (ranging 5, 10, 25 and 50μg/ml) exhibited amoebicidal effects i.e., >60% of trophozoites executed under normal light at maximum dose (50μg/ml) within 1h incubation. In contrast pure/doped TiO2 obtained via sol gel method showed ~40% amoeba damage. Furthermore, amoebae growth assay demonstrated that Zn doped TiO2 also inhibited Acanthamoeba numbers up to 7days in dose dependent manner. It was interesting to note that all the tested TiO2 nanoparticles have shown maximum amoebicidal effects at pH7 which is quite relevant to amoebic growth favorable conditions. Our results confirmed that TiO2 has inhibitory effects on Acanthamoeba growth and viability. Overall, we reported the amoebicidal and amoebic growth inhibition potential of pure and Zn doped TiO2 nanoparticles against Acanthamoeba due to attached OH(-) groups, reduced size and decreased band gap of sol hydrothermally synthesized TiO2 nanoparticles. PMID:27054875

  3. Characterization of a New Pathogenic Acanthamoeba Species, A. byersi n. sp., Isolated from a Human with Fatal Amoebic Encephalitis

    PubMed Central

    Qvarnstrom, Yvonne; Nerad, Thomas A.; Visvesvara, Govinda S.

    2015-01-01

    Acanthamoeba spp. are free-living amoebae that are ubiquitous in natural environments. They can cause cutaneous, nasopharyngeal and disseminated infection, leading to granulomatous amebic encephalitis (GAE) in immunocompromised individuals. In addition, they can cause amoebic keratitis in contact lens wearers. Acanthamoeba GAE is almost always fatal because of difficulty and delay in diagnosis and lack of optimal antimicrobial therapy. Here we report the description of an unusual strain isolated from skin and brain of a GAE patient. The amoebae displayed large trophozoites and star-shaped cysts, characteristics for acanthamoebas belonging to morphology Group 1. However, its unique morphology and growth characteristics differentiated this new strain from other Group 1 species. DNA sequence analysis, secondary structure prediction and phylogenetic analysis of the 18S rRNA gene confirmed that this new strain belonged to Group 1 but that it was distinct from the other sequence types within that group. Thus, we hereby propose the establishment of a new species, Acanthamoeba byersi n. sp. as well as a new sequence type, T18, for this new strain. To our knowledge, this is the first report of a Group 1 Acanthamoeba that is indisputably pathogenic in humans. PMID:23879685

  4. Comparative proteomic analysis of extracellular secreted proteins expressed by two pathogenic Acanthamoeba castellanii clinical isolates and a non-pathogenic ATCC strain.

    PubMed

    Huang, Jian-Ming; Lin, Wei-Chen; Li, Sung-Chou; Shih, Min-Hsiu; Chan, Wen-Ching; Shin, Jyh-Wei; Huang, Fu-Chin

    2016-07-01

    Acanthamoeba keratitis (AK) is a serious ocular disease caused by pathogenic Acanthamoeba gaining entry through wounds in the corneal injury; generally, patients at risk for contracting AK wear contact lenses, usually over a long period of time. Moreover, pathogenic Acanthamoeba causes serious consequences: it makes the cornea turbid and difficult to operate on, including procedures such as enucleation of the eyeball. At present, diagnosis of this disease is not straightforward, and treatment is very demanding. We have established the comparative transcriptome and extracellular secreted proteomic database according to the non-pathogenic strain ATCC 30010 and the pathogenic strains NCKU_B and NCKU_D. We identified 44 secreted proteins successfully, 10 consensus secreted proteins and 34 strain-specific secreted proteins. These proteins may provide targets for therapy and immuno-diagnosis of Acanthamoeba infections. This study shows a suitable approach to identify secreted proteins in Acanthamoeba and provides new perspectives for the study of molecules potentially involved in the AK.

  5. Targeting cyst wall is an effective strategy in improving the efficacy of marketed contact lens disinfecting solutions against Acanthamoeba castellanii cysts.

    PubMed

    Abjani, Farhat; Khan, Naveed Ahmed; Yousuf, Farzana Abubakar; Siddiqui, Ruqaiyyah

    2016-06-01

    Acanthamoeba cysts are highly resistant to contact lens disinfecting solutions. Acanthamoeba cyst wall is partially made of 1,4 β-glucan (i.e., cellulose) and other complex polysaccharides making it a hardy shell that protects the resident amoeba. Here, we hypothesize that targeting the cyst wall structure in addition to antiamoebic compound would improve the efficacy of marketed contact lens disinfecting solutions. Using chlorhexidine as an antiamoebic compound and cellulase enzyme to disrupt cyst wall structure, the findings revealed that combination of both agents abolished viability of Acanthamoeba castellanii cysts and trophozoites. When tested alone, none of the agents nor contact lens disinfecting solutions completely destroyed A. castellanii cysts and trophozoites. The absence of cyst wall-degrading enzymes in marketed contact lens disinfecting solutions render them ineffective against Acanthamoeba cysts. It is concluded that the addition of cyst wall degrading molecules in contact lens disinfecting solutions will enhance their efficacy in decreasing the incidence of Acanthamoeba effectively. PMID:26675112

  6. Targeting cyst wall is an effective strategy in improving the efficacy of marketed contact lens disinfecting solutions against Acanthamoeba castellanii cysts.

    PubMed

    Abjani, Farhat; Khan, Naveed Ahmed; Yousuf, Farzana Abubakar; Siddiqui, Ruqaiyyah

    2016-06-01

    Acanthamoeba cysts are highly resistant to contact lens disinfecting solutions. Acanthamoeba cyst wall is partially made of 1,4 β-glucan (i.e., cellulose) and other complex polysaccharides making it a hardy shell that protects the resident amoeba. Here, we hypothesize that targeting the cyst wall structure in addition to antiamoebic compound would improve the efficacy of marketed contact lens disinfecting solutions. Using chlorhexidine as an antiamoebic compound and cellulase enzyme to disrupt cyst wall structure, the findings revealed that combination of both agents abolished viability of Acanthamoeba castellanii cysts and trophozoites. When tested alone, none of the agents nor contact lens disinfecting solutions completely destroyed A. castellanii cysts and trophozoites. The absence of cyst wall-degrading enzymes in marketed contact lens disinfecting solutions render them ineffective against Acanthamoeba cysts. It is concluded that the addition of cyst wall degrading molecules in contact lens disinfecting solutions will enhance their efficacy in decreasing the incidence of Acanthamoeba effectively.

  7. Inhibition of 3-Hydroxy-3-Methylglutaryl–Coenzyme A Reductase and Application of Statins as a Novel Effective Therapeutic Approach against Acanthamoeba Infections

    PubMed Central

    Lorenzo-Morales, Jacob; Machin, Rubén P.; López-Arencibia, Atteneri; García-Castellano, José Manuel; de Fuentes, Isabel; Loftus, Brendan; Maciver, Sutherland K.; Valladares, Basilio; Piñero, José E.

    2013-01-01

    Acanthamoeba is an opportunistic pathogen in humans, whose infections most commonly manifest as Acanthamoeba keratitis or, more rarely, granulomatous amoebic encephalitis. Although there are many therapeutic options for the treatment of Acanthamoeba, they are generally lengthy and/or have limited efficacy. Therefore, there is a requirement for the identification, validation, and development of novel therapeutic targets against these pathogens. Recently, RNA interference (RNAi) has been widely used for these validation purposes and has proven to be a powerful tool for Acanthamoeba therapeutics. Ergosterol is one of the major sterols in the membrane of Acanthamoeba. 3-Hydroxy-3-methylglutaryl–coenzyme A (HMG-CoA) reductase is an enzyme that catalyzes the conversion of HMG-CoA to mevalonate, one of the precursors for the production of cholesterol in humans and ergosterol in plants, fungi, and protozoa. Statins are compounds which inhibit this enzyme and so are promising as chemotherapeutics. In order to validate whether this enzyme could be an interesting therapeutic target in Acanthamoeba, small interfering RNAs (siRNAs) against HMG-CoA were developed and used to evaluate the effects induced by the inhibition of Acanthamoeba HMG-CoA. It was found that HMG-CoA is a potential drug target in these pathogenic free-living amoebae, and various statins were evaluated in vitro against three clinical strains of Acanthamoeba by using a colorimetric assay, showing important activities against the tested strains. We conclude that the targeting of HMG-CoA and Acanthamoeba treatment using statins is a novel powerful treatment option against Acanthamoeba species in human disease. PMID:23114753

  8. Design and Performance Assessment of a Stable Astigmatic Herriott Cell for Trace Gas Measurements on Airborne Platforms

    NASA Technical Reports Server (NTRS)

    Dyroff, Christoph; Fried, Alan; Richter, Dirk; Walega, James G.; Zahniser, Mark S.; McManus, J. Barry

    2005-01-01

    The present paper discusses a new, more stable, astigmatic Herriott cell employing carbon fiber stabilizing rods. Laboratory tests using a near-IR absorption feature of CO at 1564.168-nm revealed a factor of two improvement in measurement stability compared with the present commercial design when the sampling pressure was changed by +/-2 Torr around 50 Torr. This new cell should significantly enhance our efforts to measure trace gases employing pathlengths of 100 to 200-meters on airborne platforms with minimum detectable line center absorbances of less than 10(exp -6).

  9. Air bubble in anterior chamber as indicator of full-thickness incisions in femtosecond-assisted astigmatic keratotomy.

    PubMed

    Vaddavalli, Pravin K; Hurmeric, Volkan; Yoo, Sonia H

    2011-09-01

    Femtosecond-assisted astigmatic keratotomy is predictable and precise but may occasionally lead to a full-thickness incision on the cornea and the attendant complications. The presence of an air bubble in the anterior chamber soon after creation of the keratotomy by the femtosecond laser may indicate a full-thickness incision. We present a case in which recognition of this clinical finding early in the procedure might have prevented undesirable complications, such as leakage of aqueous and the potential for intraocular infection.

  10. Prevalence of Acanthamoeba spp. and other free-living amoebae in household water, Ohio, USA--1990-1992.

    PubMed

    Stockman, Lauren J; Wright, Carolyn J; Visvesvara, Govinda S; Fields, Barry S; Beach, Michael J

    2011-03-01

    Knowledge of the prevalence of free-living amoebae (FLA) in US household water can provide a focus for prevention of amoeba-associated illnesses. Household water samples from two Ohio counties, collected and examined for amoebae during 1990-1992, were used to describe the prevalence of Acanthamoeba and other FLA in a household setting. Amoebae were isolated and identified by morphologic features. A total of 2,454 samples from 467 households were examined. Amoebae were found in water samples of 371 (79%) households. Sites most likely to contain amoeba were shower heads (52%) and kitchen sprayers (50%). Species of Hartmannella, Acanthamoeba, or Vahlkampfia were most common. Detection was higher in biofilm swab samples than in water samples. Detection of FLA and Acanthamoeba, at 79% and 51%, respectively, exceed estimates that have been published in previous surveys of household sources. We believe FLA are commonplace inhabitants of household water in this sample as they are in the environment.

  11. The use of dimethyl sulfoxide in contact lens disinfectants is a potential preventative strategy against contracting Acanthamoeba keratitis.

    PubMed

    Siddiqui, Ruqaiyyah; Aqeel, Yousuf; Khan, Naveed Ahmed

    2016-10-01

    Acanthamoeba castellanii is the causative agent of blinding keratitis. Though reported in non-contact lens wearers, it is most frequently associated with improper use of contact lens. For contact lens wearers, amoebae attachment to the lens is a critical first step, followed by amoebae binding to the corneal epithelial cells during extended lens wear. Acanthamoeba attachment to surfaces (biological or inert) and migration is an active process and occurs during the trophozoite stage. Thus retaining amoebae in the cyst stage (dormant form) offers an added preventative measure in impeding parasite traversal from the contact lens onto the cornea. Here, we showed that as low as 3% DMSO, abolished A. castellanii excystation. Based on the findings, it is proposed that DMSO should be included in the contact lens disinfectants as an added preventative strategy against contracting Acanthamoeba keratitis.

  12. Prevalence of pathogenic Acanthamoeba (Protozoa:Amoebidae) in the atmosphere of the city of San Luis Potosi, Mexico.

    PubMed

    Rodriguez-Zaragoza, S; Magana-Becerra, A

    1997-01-01

    Several species of pathogenic Acanthamoeba cause infections to humans, but amoebic keratitis is more frequently found than any other due to the increasing number of contact lens wearers in the world. Cysts and trophozoites of these amebas are airborne and may pollute water from the air. We investigated the proportion of pathogenic Acanthamoeba from the atmosphere of the city of San Luis Potosi. Samples were taken by the impinger method, every month during one year. We isolated 23 strains of Acanthamoeba, 61% of them were non-pathogenic, 31% were non-pathogenic with invasive capacity and 8% were pathogenic to mice. Almost 40% of these strains represent danger of infections to humans. The isolations were more abundant during the dry season in the south (urban) and west (suburban) stations, which means that the sanitary conditions around stands may enhance the proportion of pathogenic strains in the surroundings.

  13. The role of domestic tap water on Acanthamoeba keratitis in non-contact lens wearers and validation of laboratory methods.

    PubMed

    Koltas, Ismail Soner; Eroglu, Fadime; Erdem, Elif; Yagmur, Meltem; Tanır, Ferdi

    2015-09-01

    Acanthamoeba is increasingly recognized as an important cause of keratitis in non-contact lens wearers while contact lens wear is the leading risk factor for Acanthamoeba keratitis (AK). It is unlikely that the Acanthamoeba colonization is a feature which is effective only in patient's homes with infectious keratitis since the organism has been isolated from domestic tap water. Two hundred and thirty-one (231) corneal scrapings were taken from infectious keratitis cases, and four contact lens solutions and domestic tap waters were taken from 22 out of 44 AK-diagnosed patient's homes. Microscopic examination, culture, PCR, real-time PCR and DNA sequencing analyses were used for AK-diagnosed samples. The real-time PCR was the most sensitive (100 %) one among the methods used in diagnosis of AK. The 44 (19.0 %) out of 231 corneal scrapings, 4/4 (100 %) contact lens solution and 11/22 (50 %) of domestic tap water samples were found to be positive by real-time PCR for Acanthamoeba. A. griffini (T3), A. castellanii (T4) and A. jacobsi (T15) genotypes were obtained from corneal scrapings, contact lens solutions and domestic tap water samples taken from the patient's homes diagnosed with AK. The isolation of Acanthamoeba containing 6/22 (27.3 %) A. griffini (T3), 14/22 (63.6 %) A. castellanii (T4) and 2/22 (9.1 %) A. jacobsi (T15) from the domestic tap water outlets of 22 of 44 (50 %) of patient's homes revealed that is a significant source of these organisms. A. griffini (T3) and A. jacobsi (T15) genotypes have not been determined from AK cases in Turkey previously. Thus, we conclude that Acanthamoeba keratitis is associated with exposition of patients who has ocular trauma or ocular surface disease to domestic tap water in endemic or potentially endemic countries. PMID:26017346

  14. The role of domestic tap water on Acanthamoeba keratitis in non-contact lens wearers and validation of laboratory methods.

    PubMed

    Koltas, Ismail Soner; Eroglu, Fadime; Erdem, Elif; Yagmur, Meltem; Tanır, Ferdi

    2015-09-01

    Acanthamoeba is increasingly recognized as an important cause of keratitis in non-contact lens wearers while contact lens wear is the leading risk factor for Acanthamoeba keratitis (AK). It is unlikely that the Acanthamoeba colonization is a feature which is effective only in patient's homes with infectious keratitis since the organism has been isolated from domestic tap water. Two hundred and thirty-one (231) corneal scrapings were taken from infectious keratitis cases, and four contact lens solutions and domestic tap waters were taken from 22 out of 44 AK-diagnosed patient's homes. Microscopic examination, culture, PCR, real-time PCR and DNA sequencing analyses were used for AK-diagnosed samples. The real-time PCR was the most sensitive (100 %) one among the methods used in diagnosis of AK. The 44 (19.0 %) out of 231 corneal scrapings, 4/4 (100 %) contact lens solution and 11/22 (50 %) of domestic tap water samples were found to be positive by real-time PCR for Acanthamoeba. A. griffini (T3), A. castellanii (T4) and A. jacobsi (T15) genotypes were obtained from corneal scrapings, contact lens solutions and domestic tap water samples taken from the patient's homes diagnosed with AK. The isolation of Acanthamoeba containing 6/22 (27.3 %) A. griffini (T3), 14/22 (63.6 %) A. castellanii (T4) and 2/22 (9.1 %) A. jacobsi (T15) from the domestic tap water outlets of 22 of 44 (50 %) of patient's homes revealed that is a significant source of these organisms. A. griffini (T3) and A. jacobsi (T15) genotypes have not been determined from AK cases in Turkey previously. Thus, we conclude that Acanthamoeba keratitis is associated with exposition of patients who has ocular trauma or ocular surface disease to domestic tap water in endemic or potentially endemic countries.

  15. An Explicitly Solvable Case of the Construction of the Fundamental Cavity Mode in the Form of a Gaussian Beam with a Complex Astigmatism

    NASA Astrophysics Data System (ADS)

    Kudashov, V. N.; Plachenov, A. B.; Radin, A. M.

    2000-01-01

    An analysis is carried out of the ring cavities whose fundamental modes represent Gaussian beams with complex astigmatism. The analysis is made for the case where the block B or C in the cavity ray matrix ABCD of dimension 4×4 is a symmetric nondegenerate matrix. Explicit formulas are obtained, which permits the expression of beam characteristics directly in terms of the cavity ray matrix without the laborious process of finding its eigenvectors. The results obtained in the study can be used for controlling astigmatism in lasers and laser systems, the calculation of polarization of three-dimensional active media in linear and ring optical cavities of complex configuration, etc.

  16. Computation of astigmatic and trefoil figure errors and misalignments for two-mirror telescopes using nodal-aberration theory.

    PubMed

    Ju, Guohao; Yan, Changxiang; Gu, Zhiyuan; Ma, Hongcai

    2016-05-01

    In active optics systems, one concern is how to quantitatively separate the effects of astigmatic and trefoil figure errors and misalignments that couple together in determining the total aberration fields when wavefront measurements are available at only a few field points. In this paper, we first quantitatively describe the impact of mount-induced trefoil deformation on the net aberration fields by proposing a modified theoretical formulation for the field-dependent aberration behavior of freeform surfaces based on the framework of nodal aberration theory. This formulation explicitly expresses the quantitative relationships between the magnitude of freeform surfaces and the induced aberration components where the freeform surfaces can be located away from the aperture stop and decentered from the optical axis. On this basis, and in combination with the mathematical presentation of nodal aberration theory for the effects of misalignments, we present the analytic expressions for the aberration fields of two-mirror telescopes in the presence of astigmatic primary mirror figure errors, mount-induced trefoil deformations on both mirrors, and misalignments. We quantitatively separate these effects using the analytical expressions with wavefront measurements at a few field points and pointing errors. Valuable insights are provided on how to separate these coupled effects in the computation process. Monte Carlo simulations are conducted to demonstrate the correctness and accuracy of the analytic method presented in this paper. PMID:27140345

  17. Generalized design of a zero-geometric-loss, astigmatism-free, modified four-objective multipass matrix system.

    PubMed

    Guo, Yin; Sun, LiQun; Yang, Zheng; Liu, Zilong

    2016-02-20

    During this study we constructed a generalized parametric modified four-objective multipass matrix system (MMS). We used an optical system comprising four asymmetrical spherical mirrors to improve the alignment process. The use of a paraxial equation for the design of the front transfer optics yielded the initial condition for modeling our MMS. We performed a ray tracing simulation to calculate the significant aberration of the system (astigmatism). Based on the calculated meridional and sagittal focus positions, the complementary focusing mirror was easily designed to provide an output beam free of astigmatism. We have presented an example of a 108-transit multipass system (5×7 matrix arrangement) with a relatively larger numerical aperture source (xenon light source). The whole system exhibits zero theoretical geometrical loss when simulated with Zemax software. The MMS construction strategy described in this study provides an anastigmatic output beam and the generalized approach to design a controllable matrix spot pattern on the field mirrors. Asymmetrical reflective mirrors aid in aligning the whole system with high efficiency. With the generalized design strategy in terms of optics configuration and asymmetrical fabrication method in this paper, other kinds of multipass matrix system coupled with different sources and detector systems also can be achieved. PMID:26906598

  18. Computation of astigmatic and trefoil figure errors and misalignments for two-mirror telescopes using nodal-aberration theory.

    PubMed

    Ju, Guohao; Yan, Changxiang; Gu, Zhiyuan; Ma, Hongcai

    2016-05-01

    In active optics systems, one concern is how to quantitatively separate the effects of astigmatic and trefoil figure errors and misalignments that couple together in determining the total aberration fields when wavefront measurements are available at only a few field points. In this paper, we first quantitatively describe the impact of mount-induced trefoil deformation on the net aberration fields by proposing a modified theoretical formulation for the field-dependent aberration behavior of freeform surfaces based on the framework of nodal aberration theory. This formulation explicitly expresses the quantitative relationships between the magnitude of freeform surfaces and the induced aberration components where the freeform surfaces can be located away from the aperture stop and decentered from the optical axis. On this basis, and in combination with the mathematical presentation of nodal aberration theory for the effects of misalignments, we present the analytic expressions for the aberration fields of two-mirror telescopes in the presence of astigmatic primary mirror figure errors, mount-induced trefoil deformations on both mirrors, and misalignments. We quantitatively separate these effects using the analytical expressions with wavefront measurements at a few field points and pointing errors. Valuable insights are provided on how to separate these coupled effects in the computation process. Monte Carlo simulations are conducted to demonstrate the correctness and accuracy of the analytic method presented in this paper.

  19. [Observations on Acanthamoeba trophozoites in axenic cultures and their staining characteristics with different stains].

    PubMed

    Polat, Zübeyde Akin; Ozçelik, Semra; Vural, Ayşe; Saygi, Gülendame

    2007-01-01

    Acanthamoeba spp. are among the most prevalent protozoa found in the environment. The species of this genus are the causative agents of granulomatous amebic encephalitis (GAE), a fatal disease of the central nervous system (CNS), and amebic keratitis (AK), a painful sight-threatening disease of the eye. In this study we have used two species of Acanthamoeba, Acanthamoeba castellanii and A. hatchetti, both were obtained from Vienna, Austria. They were cultivated on non-nutritious agar seeded with Escherichia coli and PPYG (protease peptone-yeast extract-glucose) medium. Our aim was to concentrate on three points in relation to the trophozoites and cysts stages of these species as follows: (i) to observe their morphology, (ii). to confirm our previous observation of a canal between two trophozoites. The bridge-like connection between these trophozoites greatly resembled the one that can be observed in conjugation during an exchange of genetic material. Two tro-phozoites with a bridge-like extension between them keep their position for at least 200 minutes. (iii). to detect the reactions of trophozoites to various stains. According to our findings in regard to these three points: (i). trophozoites with more than one nucleus are often seen in axenic cultures. (ii). This resembles a type of conjugation with a transfer of genetic material between two trophozoites. Certainly, this needs further investigation using more sophisticated methods. (iii). trophozoites equally stained well with Heidenhain's iron haematoxylin, Giemsa, PAS, Masson Trichrome, and Toludin-O stains. However, our results with reticulin, PAP, Van Gison, Musicarmine and Orsein stains were not satisfactory.

  20. Acanthamoeba encystment: multifactorial effects of buffers, biocides, and demulcents present in contact lens care solutions

    PubMed Central

    Kovacs, Christopher J; Lynch, Shawn C; Rah, Marjorie J; Millard, Kimberly A; Morris, Timothy W

    2015-01-01

    Purpose To determine whether agents which are purportedly capable of inducing encystment of Acanthamoeba can recapitulate the signal when tested in differing formulations. Methods In accordance with the International Standard ISO 19045, Acanthamoeba castellanii ATCC 50370 trophozoites were cultured in antibiotic-free axenic medium, treated with test solutions, and encystment rates plus viability were measured via bright field and fluorescent microscopy. Test solutions included phosphate-buffered saline (PBS), borate-buffered saline, biguanide- and hydrogen peroxide (H2O2)-based biocides, propylene glycol (PG) and povidone (POV) ophthalmic demulcents, and one-step H2O2-based contact lens disinfection systems. Results Only PBS solutions with 0.25 ppm polyaminopropyl biguanide (PAPB) and increasing concentrations of PG and POV stimulated A. castellanii encystment in a dose-dependent manner, whereas PBS solutions containing 3% H2O2 and increasing concentrations of PG and POV did not stimulate encystment. Borate-buffered saline and PBS/citrate solutions containing PG also did not stimulate encystment. In addition, no encystment was observed after 24 hours, 7 days, or 14 days of exposures of trophozoites to one-step H2O2 contact lens disinfection products or related solutions. Conclusion The lack of any encystment observed when trophozoites were treated with existing or new one-step H2O2 contact lens care products, as well as when trophozoites were exposed to various related test solutions, confirms that Acanthamoeba encystment is a complex process which depends upon simultaneous contributions of multiple factors including buffers, biocides, and demulcents. PMID:26508829

  1. Meningoencephalitis due to Acanthamoeba SP. Pathogenesis and clinico-pathological study.

    PubMed

    Martínez, A J; Sotelo-Avila, C; Garcia-Tamayo, J; Morón, J T; Willaert, E; Stamm, W P

    1977-03-31

    Amebic Meningoencephalitis (AM) and Primary Amebic Meningoencephalitis (PAM) are infectious diseases essentially confined to the Central Nervous System (CNS) and caused by free-living amebas of the genus Acanthamoeba (A.) and Naegleria (N.) respectively. AM due to A. sp. (Acanthamoeba castellanii and Acanthamoeba culbertsoni) have been reported in chronically ill debilitated individuals, some of them under immunosuppressive therapy, or in immunologically impaired patients without a history of recent swimming in contrast to cases due to N. sp. which usually occurs in healthy, young individuals with a recent history of swimming in man-made lakes or heated swimming pools. AM due to A.sp. is characterized by a subacute or chronic granulomatous meningoencephalitis involving mainly the midbrain, basal areas of the temporal and occipital lobes and posterior fossa structures. CNS lesions in AM are perhaps secondary and the portal of entry in humans is probably from the lower respiratory tract, genitourinary system or skin reaching the CNS by hematogenous spread. The predominant host reaction is usually composed of lymphocytes, plasma cells, monocytes and multinucleated foreign body giant cells. Necrosis is moderate and hemorrhage scant or absent. Cysts as well as trophozoites may be seen within the CNS lesions. PAM is due to Naegleria fowleri and is characterized by an hemorrhagic necrotizing meningoencephalities with an acute inflammatory response. Only trophozoites are found in lesions. The portal of entry is through the olfactory neuroepithelium. CNS tissues fixed in formalin may be used for further identification and taxonomical classification of the causative protoza using immunofluorescent antibody techniques (IFAT) and electron microscopic methods. PMID:857580

  2. Interaction of Escherichia coli K1 and K5 with Acanthamoeba castellanii Trophozoites and Cysts

    PubMed Central

    Matin, Abdul

    2011-01-01

    The existence of symbiotic relationships between Acanthamoeba and a variety of bacteria is well-documented. However, the ability of Acanthamoeba interacting with host bacterial pathogens has gained particular attention. Here, to understand the interactions of Escherichia coli K1 and E. coli K5 strains with Acanthamoeba castellanii trophozoites and cysts, association assay, invasion assay, survival assay, and the measurement of bacterial numbers from cysts were performed, and nonpathogenic E. coli K12 was also applied. The association ratio of E. coli K1 with A. castellanii was 4.3 cfu per amoeba for 1 hr but E. coli K5 with A. castellanii was 1 cfu per amoeba for 1 hr. By invasion and survival assays, E. coli K5 was recovered less than E. coli K1 but still alive inside A. castellanii. E. coli K1 and K5 survived and multiplied intracellularly in A. castellanii. The survival assay was performed under a favourable condition for 22 hr and 43 hr with the encystment of A. castellanii. Under the favourable condition for the transformation of trophozoites into cysts, E. coli K5 multiplied significantly. Moreover, the pathogenic potential of E. coli K1 from A. castellanii cysts exhibited no changes as compared with E. coli K1 from A. castellanii trophozoites. E. coli K5 was multiplied in A. castellanii trophozoites and survived in A. castellanii cysts. Therefore, this study suggests that E. coli K5 can use A. castellanii as a reservoir host or a vector for the bacterial transmission. PMID:22355201

  3. Growth phase dependent alterations in the surface coat of Acanthamoeba castellanii.

    PubMed

    Przełecka, A; Sobota, A

    1982-01-01

    Application of ruthenium red, cationized ferritin and concanavalin A to exponentially growing trophozoites reveals on their plasma membrane negatively charged surface coat bearing sugar residues. In the coat of trophozoites from advanced stationary growth phase no sugar residues can be visualized. In mature cysts the external layer of their wall is negatively charged, however, on their protoplast surface no terminals reacting with the 2 polycations, or with concanavalin A can be revealed, even though the penetration of the reagents has been ensured by enzymatic impairing of the cyst wall. The results are confronted with the known facts concerning alterations of physiological properties of plasma membrane occurring during the life cycle of Acanthamoeba.

  4. Detection of free living amoebae, Acanthamoeba and Naegleria, in swimming pools, Malaysia.

    PubMed

    Init, I; Lau, Y L; Arin Fadzlun, A; Foead, A I; Neilson, R S; Nissapatorn, V

    2010-12-01

    This study reports the detection of Acanthamoeba and Naegleria species in 14 swimming pools around Petaling Jaya and Kuala Lumpur, Malaysia. Sampling was carried out at 4 sites (the platforms (P), wall (W), 1 meter from the wall (1) and middle (2)) of each swimming pool. These free living amoebae (FLA) were detected under light and inverted microscopes after being cultured on the surface of non-nutrient agar lawned with Escherichia coli. Acanthamoeba species were detected in higher number of culture plates from all sampling sites of all the swimming pools. While Naegleria, were detected in fewer culture plates at 3 sampling sites (absent at site P) of 8 swimming pools. This suggested that the thick double-walled cysts of Acanthamoeba were more resistant, thus remaining viable in the dry-hot areas of the platforms and in chlorinated water of the swimming pools whereas Naegleria cysts, that are fragile and susceptible to desiccation, preferred watery or moist areas for growth and proliferation. The prevalence of both FLA was highest at site W (76.2%), followed by site 1 (64.7%), lowest at site 2 (19.4%), and could be detected at all 3 sampling levels (top, middle and bottom) of these 3 sites. The surface of site W might act as a bio-film that accumulated all kinds of microbes providing sufficient requirement for the FLA to develop and undergo many rounds of life cycles as well as moving from top to bottom in order to graze food. Other factors such as human activities, the circulating system which was fixed at all swimming pools, blowing wind which might carry the cysts from surroundings and the swimming flagellate stage of Naegleria could also contribute to the distribution of the FLA at these sampling sites. Both FLA showed highest growth (80.4%) at room temperature (25-28 ºC) and lesser (70.0%) at 37 ºC which might be due to the overgrowth of other microbes (E. coli, fungi, algae, etc). While at 44 ºC, only Acanthamoeba species could survive thus showing that

  5. Acanthamoeba polyphaga mimivirus and other giant viruses: an open field to outstanding discoveries.

    PubMed

    Abrahão, Jônatas S; Dornas, Fábio P; Silva, Lorena C F; Almeida, Gabriel M; Boratto, Paulo V M; Colson, Phillipe; La Scola, Bernard; Kroon, Erna G

    2014-06-30

    In 2003, Acanthamoeba polyphaga mimivirus (APMV) was first described and began to impact researchers around the world, due to its structural and genetic complexity. This virus founded the family Mimiviridae. In recent years, several new giant viruses have been isolated from different environments and specimens. Giant virus research is in its initial phase and information that may arise in the coming years may change current conceptions of life, diversity and evolution. Thus, this review aims to condense the studies conducted so far about the features and peculiarities of APMV, from its discovery to its clinical relevance.

  6. A novel antiamoebic agent against Acanthamoeba sp. - A causative agent for eye keratitis infection

    NASA Astrophysics Data System (ADS)

    Kusrini, Eny; Hashim, Fatimah; Azmi, Wan Nor Nadhirah Wan Noor; Amin, Nakisah Mat; Estuningtyas, Ari

    2016-01-01

    The terbium trinitrate.trihydrate.18-crown ether-6, Tb(NO3)3(OH2)3.(18C6) complex has been characterized by elemental analysis, photoluminescence and single X-ray diffraction. The IC50 values were determined based on MTT assay while light and fluorescence microscopy imaging were employed to evaluate the cellular morphological changes. Alkaline comet assay was performed to analyze the DNA damage. The photoluminescence spectrum of the Tb complex excited at 325 nm displayed seven luminescence peaks corresponding to the 5D4 → 7F0, 1, 2, 3, 4, 5, 6 transitions. The cytotoxicity and genotoxicity studies indicated that the Tb(NO3)3(OH2)3.(18C6) complex and its salt form as well as the 18C6 molecule have excellent anti-amoebic activity with very low IC50 values are 7, 2.6 and 1.2 μg/mL, respectively, with significant decrease (p < 0.05) in Acanthamoeba viability when the concentration was increased from 0 to 30 μg/mL. The mode of cell death in Acanthamoeba cells following treatment with the Tb complex was apoptosis. This is in contrast to the Tb(NO3)3.6H2O salt- and 18C6 molecule-treated Acanthamoeba, which exhibited necrotic type cells. The percentage of DNA damage following treatment with all the compounds at the IC25 values showed high percentage of type 1 with the % nuclei damage are 14.15 ± 2.4; 46.00 ± 4.2; 36.36 ± 2.4; 45.16 ± 0.6%, respectively for untreated, treated with Tb complex, Tb salt and 18C6 molecule. The work features promising potential of Tb(NO3)3(OH2)3.(18C6) complex as anti-amoebic agent, representing a therapeutic option for Acanthamoeba keratitis infection.

  7. Acanthamoeba polyphaga mimivirus and other giant viruses: an open field to outstanding discoveries

    PubMed Central

    2014-01-01

    In 2003, Acanthamoeba polyphaga mimivirus (APMV) was first described and began to impact researchers around the world, due to its structural and genetic complexity. This virus founded the family Mimiviridae. In recent years, several new giant viruses have been isolated from different environments and specimens. Giant virus research is in its initial phase and information that may arise in the coming years may change current conceptions of life, diversity and evolution. Thus, this review aims to condense the studies conducted so far about the features and peculiarities of APMV, from its discovery to its clinical relevance. PMID:24976356

  8. A novel antiamoebic agent against Acanthamoeba sp.--A causative agent for eye keratitis infection.

    PubMed

    Kusrini, Eny; Hashim, Fatimah; Azmi, Wan Nor Nadhirah Wan Noor; Amin, Nakisah Mat; Estuningtyas, Ari

    2016-01-15

    The terbium trinitrate.trihydrate.18-crown ether-6, Tb(NO3)3(OH2)3.(18C6) complex has been characterized by elemental analysis, photoluminescence and single X-ray diffraction. The IC50 values were determined based on MTT assay while light and fluorescence microscopy imaging were employed to evaluate the cellular morphological changes. Alkaline comet assay was performed to analyze the DNA damage. The photoluminescence spectrum of the Tb complex excited at 325 nm displayed seven luminescence peaks corresponding to the (5)D4→(7)F(0, 1, 2, 3, 4, 5, 6) transitions. The cytotoxicity and genotoxicity studies indicated that the Tb(NO3)3(OH2)3.(18C6) complex and its salt form as well as the 18C6 molecule have excellent anti-amoebic activity with very low IC50 values are 7, 2.6 and 1.2 μg/mL, respectively, with significant decrease (p<0.05) in Acanthamoeba viability when the concentration was increased from 0 to 30 μg/mL. The mode of cell death in Acanthamoeba cells following treatment with the Tb complex was apoptosis. This is in contrast to the Tb(NO3)3.6H2O salt- and 18C6 molecule-treated Acanthamoeba, which exhibited necrotic type cells. The percentage of DNA damage following treatment with all the compounds at the IC25 values showed high percentage of type 1 with the % nuclei damage are 14.15±2.4; 46.00±4.2; 36.36±2.4; 45.16±0.6%, respectively for untreated, treated with Tb complex, Tb salt and 18C6 molecule. The work features promising potential of Tb(NO3)3(OH2)3.(18C6) complex as anti-amoebic agent, representing a therapeutic option for Acanthamoeba keratitis infection.

  9. Phylogenetic analysis and the evolution of the 18S rRNA gene typing system of Acanthamoeba.

    PubMed

    Fuerst, Paul A; Booton, Gregory C; Crary, Monica

    2015-01-01

    Species of Acanthamoeba were first described using morphological characters including cyst structure and cytology of nuclear division. More than 20 nominal species were proposed using these methods. Morphology, especially cyst shape and size, has proven to be plastic and dependent upon culture conditions. The DNA sequence of the nuclear small-subunit (18S) rRNA, the Rns gene, has become the most widely accepted method for rapid diagnosis and classification of Acanthamoeba. The Byers-Fuerst lab first proposed an Rns typing system in 1996. Subsequent refinements, with an increasing DNA database and analysis of diagnostic fragments within the gene, have become widely accepted by the Acanthamoeba research community. The development of the typing system, including its current state of implementation is illustrated by three cases: (i) the division between sequence types T13 and T16; (ii) the diversity within sequence supertype T2/T6, and (iii) verification of a new sequence type, designated T20. Molecular studies make clear the disconnection between phylogenetic relatedness and species names, as applied for the genus Acanthamoeba. Future reconciliation of genetic types with species names must become a priority, but the possible shortcomings of the use of a single gene when reconstructing the evolutionary history of the acanthamoebidae must also be resolved. PMID:25284310

  10. Acanthamoeba belonging to T3, T4, and T11: genotypes isolated from air-conditioning units in Santiago, Chile.

    PubMed

    Astorga, Berbeli; Lorenzo-Morales, Jacob; Martín-Navarro, Carmen M; Alarcón, Verónica; Moreno, Johanna; González, Ana C; Navarrete, Elizabeth; Piñero, José E; Valladares, Basilio

    2011-01-01

    Free-living amoebae (FLA) of the genus Acanthamoeba are widely distributed in the environment, in the air, soil, and water, and have also been isolated from air-conditioning units. The objective of this work was to investigate the presence of this genus of FLA in the air-conditioning equipment at the Institute of Public Health of Chile in Santiago, Chile. Water and air samples were collected from air-conditioning systems and were checked for the presence of Acanthamoeba spp. Positive samples were further classified at the genotype level after sequencing the highly variable diagnostic fragment 3 (DF3) region of the 18S rRNA gene. This is the first report of the T3, T4, and T11 genotypes of Acanthamoeba in air-conditioning units from Chile. Overall, the widespread distribution of potentially pathogenic Acanthamoeba strains in the studied source demands more awareness within the public and health professionals in Chile as this pathogen is emerging as a risk for human health worldwide.

  11. Monitoring of in vitro dynamics of Acanthamoeba strains isolated from infected eyes as a useful tool in keratitis management.

    PubMed

    Chomicz, Lidia; Padzik, Marcin; Szaflik, Jacek P; Nahorski, Wacław L; Kryczka, Tomasz; Szaflik, Jerzy

    2014-11-01

    Free-living amoebae of Acanthamoeba genus are ubiquitous in various parts of the world. Some species of these amoebozoans present a serious risk to human health as the causative agents of vision-threatening diseases, Acanthamoeba keratitis. Correct diagnosis requires both a clinical examination of the cornea and amoebic form identification in affected eyes. Despite advances in pharmacotherapy, the infection is difficult to diagnose and to threat. Population dynamics of five different Acanthamoeba strains cultured in vitro under bacteria-free condition in BSC medium, was monitored in terms of diagnostic and therapeutic management. The range of protozoan number in the exponential growth phase, the morpho-physiological status of amoeba forms and their ability to multiply were evaluated. Results of the studies revealed that early and continued monitoring of the strains maintained in an axenic culture showed correlation between the dynamics of cultivated amoebae and the course of the disease, differences in response to pharmacotherapy and the surgical management efficacy. Concluding, the in vitro monitoring of dynamics of Acanthamoeba strains isolated from infected corneas may be important not only for proper diagnosis but also as a useful tool in keratitis management and therapeutic prognosis.

  12. Phylogenetic analysis and the evolution of the 18S rRNA gene typing system of Acanthamoeba.

    PubMed

    Fuerst, Paul A; Booton, Gregory C; Crary, Monica

    2015-01-01

    Species of Acanthamoeba were first described using morphological characters including cyst structure and cytology of nuclear division. More than 20 nominal species were proposed using these methods. Morphology, especially cyst shape and size, has proven to be plastic and dependent upon culture conditions. The DNA sequence of the nuclear small-subunit (18S) rRNA, the Rns gene, has become the most widely accepted method for rapid diagnosis and classification of Acanthamoeba. The Byers-Fuerst lab first proposed an Rns typing system in 1996. Subsequent refinements, with an increasing DNA database and analysis of diagnostic fragments within the gene, have become widely accepted by the Acanthamoeba research community. The development of the typing system, including its current state of implementation is illustrated by three cases: (i) the division between sequence types T13 and T16; (ii) the diversity within sequence supertype T2/T6, and (iii) verification of a new sequence type, designated T20. Molecular studies make clear the disconnection between phylogenetic relatedness and species names, as applied for the genus Acanthamoeba. Future reconciliation of genetic types with species names must become a priority, but the possible shortcomings of the use of a single gene when reconstructing the evolutionary history of the acanthamoebidae must also be resolved.

  13. Severe Amoebic Placentitis in a Horse Caused by an Acanthamoeba hatchetti Isolate Identified Using Next-Generation Sequencing

    PubMed Central

    Begg, Angela P.; Todhunter, Kristen; Donahoe, Shannon L.; Krockenberger, Mark

    2014-01-01

    A case of amoebic placentitis in a mare from eastern Australia was diagnosed postpartum by histopathological examination of the placenta. The identity of the etiological agent was confirmed as Acanthamoeba hatchetti by use of diversity profiling based on a next-generation sequencing approach. PMID:24829227

  14. Temperature limitation may explain the containment of the trophozoites in the cornea during Acanthamoeba castellanii keratitis.

    PubMed

    Nielsen, Mattias Kiel; Nielsen, Kim; Hjortdal, Jesper; Sørensen, Uffe B Skov

    2014-12-01

    Acanthamoeba keratitis is a serious sight-threatening disease. The relatively low temperature of the cornea may explain why amoebic infections usually are localized in this tissue and rarely spread to other parts of the eye. In this study, the growth rate of the amoeba Acanthamoeba castellanii was examined at different temperatures. The aim was to establish the optimal growth temperature for A. castellanii and to examine the growth within the vicinity of the core body temperature. The growth rates of four clinical and two environmental strains of A. castellanii were estimated at different temperatures, and temperature limitations for the trophozoite stage was established. Movements influenced by temperature gradients were monitored for two clinical strains of A. castellanii. The highest growth rate for each of the six amoebic strains tested was found to be close to 32 °C. The growth of the trophozoites of all examined strains was greatly reduced or completely halted at temperatures above 36 °C and encysted at the elevated temperature. Thus, the optimal growth temperature for the four strains of A. castellanii is close to the surface temperature of the human cornea, while the higher body core-temperature induced encysting of the amoebae. This may explain why most amoebic eye infections are confined to the cornea. PMID:25204727

  15. Cellulose degradation: a therapeutic strategy in the improved treatment of Acanthamoeba infections.

    PubMed

    Lakhundi, Sahreena; Siddiqui, Ruqaiyyah; Khan, Naveed Ahmed

    2015-01-01

    Acanthamoeba is an opportunistic free-living amoeba that can cause blinding keratitis and fatal brain infection. Early diagnosis, followed by aggressive treatment is a pre-requisite in the successful treatment but even then the prognosis remains poor. A major drawback during the course of treatment is the ability of the amoeba to enclose itself within a shell (a process known as encystment), making it resistant to chemotherapeutic agents. As the cyst wall is partly made of cellulose, thus cellulose degradation offers a potential therapeutic strategy in the effective targeting of trophozoite encased within the cyst walls. Here, we present a comprehensive report on the structure of cellulose and cellulases, as well as known cellulose degradation mechanisms with an eye to target the Acanthamoeba cyst wall. The disruption of the cyst wall will make amoeba (concealed within) susceptible to chemotherapeutic agents, and at the very least inhibition of the excystment process will impede infection recurrence, as we bring these promising drug targets into focus so that they can be explored to their fullest.

  16. Identification of Protein Arginine Methyltransferase 5 as a Regulator for Encystation of Acanthamoeba

    PubMed Central

    Moon, Eun-Kyung; Hong, Yeonchul; Chung, Dong-Il; Goo, Youn-Kyoung; Kong, Hyun-Hee

    2016-01-01

    Encystation is an essential process for Acanthamoeba survival under nutrient-limiting conditions and exposure to drugs. The expression of several genes has been observed to increase or decrease during encystation. Epigenetic processes involved in regulation of gene expression have been shown to play a role in several pathogenic parasites. In the present study, we identified the protein arginine methyltransferase 5 (PRMT5), a known epigenetic regulator, in Acanthamoeba castellanii. PRMT5 of A. castellanii (AcPRMT5) contained domains found in S-adenosylmethionine-dependent methyltransferases and in PRMT5 arginine-N-methyltransferase. Expression levels of AcPRMT5 were increased during encystation of A. castellanii. The EGFP-PRMT5 fusion protein was mainly localized in the nucleus of trophozoites. A. castellanii transfected with siRNA designed against AcPRMT5 failed to form mature cysts. The findings of this study lead to a better understanding of epigenetic mechanisms behind the regulation of encystation in cyst-forming pathogenic protozoa. PMID:27180570

  17. Investigating the role of Acanthamoeba polyphaga in protecting Human Adenovirus from water disinfection treatment.

    PubMed

    Verani, Marco; Di Giuseppe, Graziano; Tammaro, Carmine; Carducci, Annalaura

    2016-06-01

    Human adenoviruses are responsible for a wide range of clinical infections and are present in aquatic environments, including river, seawater, drinking-water and sewage. Free-living amoebae (Acanthamoeba) in the same environments may internalize them and other microorganisms can act as a reservoir for the internalized viruses. In this study, we studied the interaction between Acanthamoeba polyphaga and Human Adenovirus type 5 (HAdV 5) to determine whether the amoeba played a role in protecting the internalized viruses from chemical disinfection. The efficacy of sodium hypochlorite disinfection against A. polyphaga and HAdV 5 either singly or in combination was assessed at three different concentrations. Individually, the amoeba were more resistant to chemical disinfection than HAdV 5 and remained alive after exposure to 5mg/l of sodium hypochlorite. In contrast, HAdV 5 lost infectivity following exposure to 2.5mg/l of sodium hypochlorite. When the amoeba and HAdV 5 were co-cultured, infectious virus was found in the cytoplasm of the amoeba at 5mg/l disinfectant concentration. These findings suggest that the A. polyphaga is providing protection for the HAdV 5. PMID:26999560

  18. Purification from Acanthamoeba castellanii of proteins that induce gelation and syneresis of F-actin.

    PubMed

    Maruta, H; Korn, E D

    1977-01-10

    From Acanthamoeba castellanii, we have purified four proteins each of which alone causes a solution of F-actin to gel. The four active proteins have subunit molecular weights of about 23,000, 28,000, 32,000 and 38,000, respectively; the last three may be dimers in their native proteins. Together, these four proteins account for about 97% of the gelation activity of the whole extract; not more than about 3% of the total activity of the unfractionated extract can be due to a 250,000-dalton polypeptide. Another protein fraction, purified by agarose chromatography, induces shrinking (syneresis) of gels formed from F-actin and any of the gelation factors. That fraction contains a high Ca2+-, low (K+,EDTA)-ATPase and a major polypeptide of 170,000 daltons both of which bind to actin in the shrunken gel pellet. The active fraction does not contain the previously described Acanthamoeba myosin (Pollard, T. D., and Korn, E. D. (1973) J. Biol. Chem. 248, 4682-4690).

  19. Campylobacter jejuni actively invades the amoeba Acanthamoeba polyphaga and survives within non digestive vacuoles.

    PubMed

    Olofsson, Jenny; Axelsson-Olsson, Diana; Brudin, Lars; Olsen, Björn; Ellström, Patrik

    2013-01-01

    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 spacious vacuoles that were part of the degradative pathway as determined by the uptake of fluorescently labeled dextran. The amount of heat killed bacteria internalized by A. polyphaga did never reach the maximal amount of internalized viable bacteria. These results suggest that the uptake and intracellular survival of C. jejuni in A. polyphaga is bacterially induced. PMID:24223169

  20. Behavior of Yersinia enterocolitica in the presence of the bacterivorous Acanthamoeba castellanii.

    PubMed

    Lambrecht, E; Baré, J; Van Damme, I; Bert, W; Sabbe, K; Houf, K

    2013-10-01

    Free-living protozoa play an important role in the ecology and epidemiology of human-pathogenic bacteria. In the present study, the interaction between Yersinia enterocolitica, an important food-borne pathogen, and the free-living amoeba Acanthamoeba castellanii was studied. Several cocultivation assays were set up to assess the resistance of Y. enterocolitica to A. castellanii predation and the impact of environmental factors and bacterial strain-specific characteristics. Results showed that all Y. enterocolitica strains persist in association with A. castellanii for at least 14 days, and associations with A. castellanii enhanced survival of Yersinia under nutrient-rich conditions at 25°C and under nutrient-poor conditions at 37°C. Amoebae cultivated in the supernatant of one Yersinia strain showed temperature- and time-dependent permeabilization. Intraprotozoan survival of Y. enterocolitica depended on nutrient availability and temperature, with up to 2.8 log CFU/ml bacteria displaying intracellular survival at 7°C for at least 4 days in nutrient-rich medium. Transmission electron microscopy was performed to locate the Yersinia cells inside the amoebae. As Yersinia and Acanthamoeba share similar ecological niches, this interaction identifies a role of free-living protozoa in the ecology and epidemiology of Y. enterocolitica. PMID:23934496

  1. Acanthamoeba castellanii metabolites increase the intracellular calcium level and cause cytotoxicity in wish cells.

    PubMed

    Mattana, A; Bennardini, F; Usai, S; Fiori, P L; Franconi, F; Cappuccinelli, P

    1997-08-01

    Previous studies have shown that trophozoites of the pathogenic free-living amoeba Acanthamoeba castellanii rapidly lyse a variety of cells in vitro. However, the role played by cytolitic molecules that may participate in Acanthamoebal cytopathogenicity has yet to be completely elucidated. The aim of this work was to study whether soluble molecules released by A. castellanii trophozoites could induce cytopathic effect in human epithelial cells in vitro. The results obtained indicate that A. castellanii trophozoites constitutively elaborate and release soluble factors that immediately elicit a cytosolic free-calcium increase in target cells. This phenomenon is induced by low molecular weight amoebic metabolites and depends on a transmembrane influx of extracellular calcium. Morphological changes, cytoskeletal damage, cell death and cytolysis followed the elevation of cytosolic free-calcium levels. Calcium ions are very important for cell homeostasis, in fact, they control the functions of a variety of cellular responses, including secretion, cell proliferation and apoptosis. Our results suggest that the substained elevation of the cytosolic free-calcium in response to A. castellanii metabolites might play a fundamental role in target cell damage during Acanthamoeba infections. PMID:9245619

  2. Acanthamoeba castellanii : growth on human cell layers reactivates attenuated properties after prolonged axenic culture

    PubMed Central

    Koehsler, Martina; Leitsch, David; Duchêne, Michael; Nagl, Markus; Walochnik, Julia

    2009-01-01

    The free-living, but potentially pathogenic, bacteriovorous amoebae of the genus Acanthamoeba can be easily grown axenically in a laboratory culture. This, however, often leads to considerable losses in virulence, and encystment capacity, and to changes in drug susceptibility. We evaluated potential options for a reactivation of a number of physiological properties, attenuated by prolonged axenic laboratory culture, including encystment potential, protease activity, heat resistance, growth rates and drug susceptibility against N-chlorotaurine (NCT). Toward this end, a strain that had been grown axenically for 10 years was repeatedly passaged on human HEp-2 cell monolayers or treated with 5′-azacytidine (AzaC), a methyltransferase inhibitor, and trichostatin A (TSA), a histone deacetylase inhibitor, in order to uplift epigenetic gene regulation. Culture on human cell monolayers resulted in significantly enhanced encystment potentials and protease activities, and higher susceptibility against NCT, whereas the resistance against heat shock was not altered. Treatment with AzaC/TSA resulted in increased encystment rates and protease activities, indicating the participation of epigenetic mechanisms. However, lowered resistances against heat shock indicate that possible stress responses to AzaC/TSA have to be taken into account. Repeated growth on human cell monolayers appears to be a potential method to reactivate attenuated characteristics in Acanthamoeba. PMID:19732153

  3. Molecular characterization of Acanthamoeba strains isolated from domestic dogs in Tenerife, Canary Islands, Spain.

    PubMed

    Valladares, María; Reyes-Batlle, María; Martín-Navarro, Carmen M; López-Arencibia, Atteneri; Dorta-Gorrín, Alexis; Wagner, Carolina; Martínez-Carretero, Enrique; Piñero, José E; Valladares, Basilio; Lorenzo-Morales, Jacob

    2015-06-01

    The present study describes two cases of Acanthamoeba infections (keratitis and ascites/peritonitis) in small breed domestic dogs in Tenerife, Canary Islands, Spain. In both cases, amoebic trophozoites were observed under the inverted microscope and isolated from the infected tissues and/or fluids, without detecting the presence of other viral, fungal or bacterial pathogens. Amoebae were isolated using 2 % non-nutrient agar plates and axenified for further biochemical and molecular analyses. Osmotolerance and thermotolerance assays revealed that both isolates were able to grow up to 37 °C and 1 M of mannitol and were thus considered as potentially pathogenic. Moreover, the strains were classified as highly cytotoxic as they cause more than 75 % of toxicity when incubated with two eukaryotic cell lines. In order to classify the strains at the molecular level, the diagnostic fragment 3 (DF3) region of the 18S rDNA of Acanthamoeba was amplified and sequenced, revealing that both isolates belonged to genotype T4. In both cases, owners of the animals did not allow any further studies or follow-up and therefore the current status of these animals is unknown. Furthermore, the isolation of these pathogenic amoebae should raise awareness with the veterinary community locally and worldwide.

  4. Restriction fragment length polymorphisms of the DNA of selected Naegleria and Acanthamoeba amebae.

    PubMed

    McLaughlin, G L; Brandt, F H; Visvesvara, G S

    1988-09-01

    Fourteen strains of Naegleria fowleri, two strains of N. gruberi, and one strain each of N. australiensis, N. jadini, N. lovaniensis, Acanthamoeba sp., A. castellanii, A. polyphaga, and A. comandoni isolated from patients, soil, or water were characterized by restriction fragment length polymorphisms. Total cellular DNA (1 microgram) was digested with either HindIII, BglII, or EcoRI; separated on agarose gels; and stained with ethidium bromide. From 2 to 15 unusually prominent repetitive restriction fragment bands, totaling 15 to 50 kilobases in length and constituting probably more than 30% of the total DNA, were detected for all ameba strains. Each species displayed a characteristic pattern of repetitive restriction fragments. Digests of the four Acanthamoeba spp. displayed fewer, less intensely staining repetitive fragments than those of the Naegleria spp. All N. fowleri strains, whether isolated from the cerebrospinal fluid of patients from different parts of the world or from hot springs, had repetitive restriction fragment bands of similar total lengths (ca. 45 kilobases), and most repetitive bands displayed identical mobilities. However, polymorphic bands were useful in identifying particular isolates. Restriction fragment length polymorphism analysis generally was consistent with taxonomy based on studies of infectivity, morphology, isoenzyme patterns, and antibody reactivity and suggests that this technique may help classify amebae isolated from clinical specimens or from the environment.

  5. Morphological Features and In Vitro Cytopathic Effect of Acanthamoeba griffini Trophozoites Isolated from a Clinical Case

    PubMed Central

    González-Robles, Arturo; Salazar-Villatoro, Lizbeth; Omaña-Molina, Maritza; Reyes-Batlle, Maria; Martín-Navarro, Carmen M.; Lorenzo-Morales, Jacob

    2014-01-01

    Light and transmission electron microscopy observations are reported on the structure and in vitro cytopathic effect of Acanthamoeba griffini trophozoites isolated from a clinical case. Live trophozoites were moderately active with a remarkable pleomorphism which changed from ovoid to quite elongated shapes. When moving, amoebae formed cytoplasmic projections such as wide lamellae and acanthopodia of diverse size and thickness which contain a significant amount of actin. Ultrastructurally, the cytoplasm showed the main organelles found in other free-living amoebae. Coincubation of trophozoites with MDCK cell monolayers resulted in a local damage to target cells after 24 h of interaction, suggesting that the cytopathic effect is contact-dependent. By transmission electron microscopy, amoebae appeared to engulf small portions of the MDCK cells; however, the cells that were not in contact with trophozoites had an unaltered morphology. When epithelial monolayers were incubated with conditioned medium for 24 h, small areas of cell injury were also observed. The phylogenetical analysis as well as the sequencing of the acquired amplified product for the DF3 region of the amoebae isolate confirmed that it belongs to genotype T3, which includes other pathogenic amoebae; besides the activity of two drugs currently used against Acanthamoeba was tested on A. griffini. PMID:25313337

  6. Interactions of Pseudomonas aeruginosa and Corynebacterium spp. with non-phagocytic brain microvascular endothelial cells and phagocytic Acanthamoeba castellanii.

    PubMed

    Siddiqui, Ruqaiyyah; Lakhundi, Sahreena; Khan, Naveed Ahmed

    2015-06-01

    Several lines of evidence suggest that Acanthamoeba interact with bacteria, which may aid in pathogenic bacterial transmission to susceptible hosts, and these interactions may have influenced evolution of bacterial pathogenicity. In this study, we tested if Gram-negative Pseudomonas aeruginosa and Gram-positive Corynebacterium spp. can associate/invade and survive inside Acanthamoeba castellanii trophozoites and cysts, as well as non-phagocytic human brain microvascular endothelial cells. The results revealed that both Corynebacterium spp. and P. aeruginosa were able to associate as well as invade and/or taken up by the phagocytic A. castellanii trophozoite. In contrast, P. aeruginosa exhibited higher association as well as invasion of non-phagocytic HBMEC compared with Corynebacterium spp. Notably, P. aeruginosa remained viable during the encystment process and exhibited higher levels of recovery from mature cysts (74.54 bacteria per amoebae) compared with Corynebacterium spp. (2.69 bacteria per amoeba) (P < 0.05). As Acanthamoeba cysts can be airborne, these findings suggest that Acanthamoeba is a potential vector in the transmission of P. aeruginosa to susceptible hosts. When bacterial-ridden amoebae were exposed to favourable (nutrient-rich) conditions, A. castellanii emerged as vegetative trophozoites and remained viable, and likewise viable P. aeruginosa were also observed but rarely any Corynebacterium spp. were observed. Correspondingly, P. aeruginosa but not Corynebacterium spp. exhibited higher cytotoxicity to non-phagocytic HBMEC, producing more than 75% cell death in 24 h, compared to 20% cell death observed with Corynebacterium spp. Additionally, it was observed that the bacterial conditioned medium had no negative effect on A. castellanii growth. Further characterization of amoebal and bacterial interactions will assist in identifying the role of Acanthamoeba in the transmission and evolution of pathogenic bacteria. PMID:25792227

  7. Methods for calculating the vergence of an astigmatic ray bundle in an optical system that contains a freeform surface

    NASA Astrophysics Data System (ADS)

    Shirayanagi, Moriyasu

    2016-07-01

    A method using the generalized Coddington equations enables calculating the vergence of an astigmatic ray bundle in the vicinity of a skew ray in an optical system containing a freeform surface. Because this method requires time-consuming calculations, however, there is still room for increasing the calculation speed. In addition, this method cannot be applied to optical systems containing a medium with a gradient index. Therefore, we propose two new calculation methods in this paper. The first method, using differential ray tracing, enables us to shorten computation time by using simpler algorithms than those used by conventional methods. The second method, using proximate rays, employs only the ray data obtained from the rays exiting an optical system. Therefore, this method can be applied to an optical system that contains a medium with a gradient index. We show some sample applications of these methods in the field of ophthalmic optics.

  8. Occurrence and molecular characterization of free-living amoeba species (Acanthamoeba, Hartmannella, and Saccamoeba limax) in various surface water resources of Iran.

    PubMed

    Mahmoudi, Mohammad Reza; Rahmati, Behnaz; Seyedpour, Seyed Hosssen; Karanis, Panagiotis

    2015-12-01

    This study was conducted to determine the presence and molecular identity of Acanthamoeba species in the surface water resources of four provinces in Iran, namely Guilan, Mazandaran (North of Iran), Alborz, and Tehran (capital city), using culture- and molecular-based methods. During March to November 2014, 49 surface water samples were collected from environmental water sources-the distinct surface waters of Guilan, Mazandaran, Alborz, and Tehran provinces, in Iran. For the isolation of Acanthamoeba species, approximately 500 ml of the water samples were filtered through a cellulose nitrate membrane with a pore size of 0.45 μ. The filter was transferred onto non-nutrient agar plates seeded with Gram-negative bacteria (Escherichia coli) as a food source. The presence of Acanthamoeba was confirmed by the genus-specific primer pair JDP1 and 2, and/or NA primers were used to identify Acanthamoeba and certain other free-living amoebae. In total, 38 out of 49 samples were positive by culture and/or PCR for Acanthamoeba and other free-living amoebae from all three provinces. By sequencing the positive isolates, the strains were shown to belong to Acanthamoeba (16 isolates belonged to T4 and 2 isolates belonged to T5), Hartmannella vermiformis (3/24), and Saccamoeba limax (2/24). The T4 and T5 genotypes were detected in Guilan and Mazandaran provinces. Two isolates from Guilan and Tehran provinces belonged to S. limax, and H. vermiformis was detected in Guilan province. The results of this study highlight the need to pay more attention to free-living amoebae, as human activity was observed in all of the localities from which these samples were taken. These surface waters can be potential sources for the distribution and transmission of pathogenic Acanthamoeba in the study areas, and free-living amoebas (FLA) (particularly the Acanthamoeba species) can serve as hosts for and vehicles of various microorganisms.

  9. Use of 18S rRNA Gene-Based PCR Assay for Diagnosis of Acanthamoeba Keratitis in Non-Contact Lens Wearers in India

    PubMed Central

    Pasricha, Gunisha; Sharma, Savitri; Garg, Prashant; Aggarwal, Ramesh K.

    2003-01-01

    Identification of Acanthamoeba cysts and trophozoites in ocular tissues requires considerable expertise and is often time-consuming. An 18S rRNA gene-based PCR test, highly specific for the genus Acanthamoeba, has recently been reported in the molecular diagnosis of Acanthamoeba keratitis. This PCR assay was compared with conventional microbiological tests for the diagnosis of Acanthamoeba keratitis. In a pilot study, the PCR conditions with modifications were first tested on corneal scrapings from patients with culture-proven non-contact lens-related Acanthamoeba, bacterial, and fungal keratitis. This was followed by testing of corneal scrapings from 53 consecutive cases of microbial keratitis to determine sensitivity, specificity, and predictive values of the assay. All corneal scrapings from patients with proven Acanthamoeba keratitis showed a 463-bp amplicon, while no amplicon was obtained from patients with bacterial or fungal keratitis. Some of these amplified products were sequenced and compared with EMBL database reference sequences to validate these to be of Acanthamoeba origin. Out of 53 consecutive cases of microbial keratitis included for evaluating the PCR, 10 (18.9%) cases were diagnosed as Acanthamoeba keratitis on the basis of combined results of culture, smear, and PCR of corneal scrapings. Based on culture results as the “gold standard,” the sensitivity of PCR was the same as that of the smear (87.5%); however, the specificity and the positive and negative predictive values of PCR were marginally higher than the smear examination (97.8 versus 95.6%, 87.5 versus 77.8%, and 97.8 versus 97.7%) although the difference was not significant. This study confirms the efficacy of the PCR assay and is the first study to evaluate a PCR-based assay against conventional methods of diagnosis in a clinical setting. PMID:12843065

  10. Isolation and molecular characterization of potentially pathogenic Acanthamoeba genotypes from diverse water resources including household drinking water from Khyber Pakhtunkhwa, Pakistan.

    PubMed

    Tanveer, Tania; Hameed, Abdul; Muazzam, Ambreen Gul; Jung, Suk-Yul; Gul, Asma; Matin, Abdul

    2013-08-01

    Acanthamoeba, an opportunistic protozoan pathogen, is ubiquitous in nature, and therefore plays a predatory role and helps control microbial communities in the ecosystem. These Acanthamoeba species are recognized as opportunistic human pathogens that may cause blinding keratitis and rare but fatal granulomatous encephalitis. To date, there is not a single report demonstrating Acanthamoeba isolation and identification from environmental sources in Pakistan, and that is the aim of this study. Acanthamoeba were identified by morphological characteristics of their cysts on non-nutrient agar plates seeded with Escherichia coli. Additionally, the polymerase chain reaction (PCR) was performed with genus-specific primers followed by direct sequencing of the PCR product for molecular identification. Furthermore, our PCR and sequencing results confirmed seven different pathogenic and nonpathogenic genotypes, including T2-T10, T4, T5, T7, T15, T16, and T17. To the best of our knowledge, we have identified and isolated Acanthamoeba sp., for the first time, from water resources of Khyber Pakhtunkhwa, Pakistan. There is an urgent need to address (1) the pathogenic potential of the identified genotypes and (2) explore other environmental sources from the country to examine the water quality and the current status of Acanthamoeba species in Pakistan, which may be a potential threat for public health across the country.

  11. The role of Src kinase in the biology and pathogenesis of Acanthamoeba castellanii

    PubMed Central

    2012-01-01

    Background Acanthamoeba species are the causative agents of fatal granulomatous encephalitis in humans. Haematogenous spread is thought to be a primary step, followed by blood–brain barrier penetration, in the transmission of Acanthmaoeba into the central nervous system, but the associated molecular mechanisms remain unclear. Here, we evaluated the role of Src, a non-receptor protein tyrosine kinase in the biology and pathogenesis of Acanthamoeba. Methods Amoebistatic and amoebicidal assays were performed by incubating amoeba in the presence of Src kinase-selective inhibitor, PP2 (4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine) and its inactive analog, PP3 (4-amino-7-phenylpyrazolo[3,4-d]pyrimidine). Using this inhibitor, the role of Src kinase in A. castellanii interactions with Escherichia coli was determined. Zymographic assays were performed to study effects of Src kinase on extracellular proteolytic activities of A. castellanii. The human brain microvascular endothelial cells were used to determine the effects of Src kinase on A. castellanii adhesion to and cytotoxicity of host cells. Results Inhibition of Src kinase using a specific inhibitor, PP2 (4-amino-5-(4 chlorophenyl)-7-(t-butyl)pyrazolo [3,4-d] pyrimidine) but not its inactive analog, PP3 (4-amino-7-phenylpyrazolo[3,4-d] pyrimidine), had detrimental effects on the growth of A. castellanii (keratitis isolate, belonging to the T4 genotype). Interestingly, inhibition of Src kinase hampered the phagocytic ability of A. castellanii, as measured by the uptake of non-invasive bacteria, but, on the contrary, invasion by pathogenic bacteria was enhanced. Zymographic assays revealed that inhibition of Src kinases reduced extracellular protease activities of A. castellanii. Src kinase inhibition had no significant effect on A. castellanii binding to and cytotoxicity of primary human brain microvascular endothelial cells, which constitute the blood–brain barrier. Conclusions For the first

  12. Raman spectroscopic study on the excystation process in a single unicellular organism amoeba (Acanthamoeba polyphaga).

    PubMed

    Lin, Yu-Chung; Perevedentseva, Elena; Cheng, Chia-Liang

    2015-05-01

    An in vivo Raman spectroscopic study of amoeba (Acanthamoeba polyphaga) is presented. The changes of the spectra during the amoeba cyst activation and excystation are analyzed. The spectra show the changes of the relative intensities of bands corresponding to protein, lipid, and carotenoid components during cyst activation. The presence of carotenoids in the amoeba is observed via characteristic Raman bands. These signals in the Raman spectra are intense in cysts but decrease in intensity with cyst activation and exhibit a correlation with the life cycle of amoeba. This work demonstrates the feasibility of using Raman spectroscopy for the detection of single amoeba microorganisms in vivo and for the analysis of the amoeba life activity. The information obtained may have implications for the estimation of epidemiological situations and for the diagnostics and prognosis of the development of amoebic inflammations.

  13. An intracellular replication niche for Vibrio cholerae in the amoeba Acanthamoeba castellanii.

    PubMed

    Van der Henst, Charles; Scrignari, Tiziana; Maclachlan, Catherine; Blokesch, Melanie

    2016-04-01

    Vibrio cholerae is a human pathogen and the causative agent of cholera. The persistence of this bacterium in aquatic environments is a key epidemiological concern, as cholera is transmitted through contaminated water. Predatory protists, such as amoebae, are major regulators of bacterial populations in such environments. Therefore, we investigated the interaction between V. cholerae and the amoeba Acanthamoeba castellanii at the single-cell level. We observed that V. cholerae can resist intracellular killing. The non-digested bacteria were either released or, alternatively, established a replication niche within the contractile vacuole of A. castellanii. V. cholerae was maintained within this compartment even upon encystment. The pathogen ultimately returned to its aquatic habitat through lysis of A. castellanii, a process that was dependent on the production of extracellular polysaccharide by the pathogen. This study reinforces the concept that V. cholerae is a facultative intracellular bacterium and describes a new host-pathogen interaction.

  14. Raman spectroscopic study on the excystation process in a single unicellular organism amoeba (Acanthamoeba polyphaga)

    NASA Astrophysics Data System (ADS)

    Lin, Yu-Chung; Perevedentseva, Elena; Cheng, Chia-Liang

    2015-05-01

    An in vivo Raman spectroscopic study of amoeba (Acanthamoeba polyphaga) is presented. The changes of the spectra during the amoeba cyst activation and excystation are analyzed. The spectra show the changes of the relative intensities of bands corresponding to protein, lipid, and carotenoid components during cyst activation. The presence of carotenoids in the amoeba is observed via characteristic Raman bands. These signals in the Raman spectra are intense in cysts but decrease in intensity with cyst activation and exhibit a correlation with the life cycle of amoeba. This work demonstrates the feasibility of using Raman spectroscopy for the detection of single amoeba microorganisms in vivo and for the analysis of the amoeba life activity. The information obtained may have implications for the estimation of epidemiological situations and for the diagnostics and prognosis of the development of amoebic inflammations.

  15. An intracellular replication niche for Vibrio cholerae in the amoeba Acanthamoeba castellanii

    PubMed Central

    Van der Henst, Charles; Scrignari, Tiziana; Maclachlan, Catherine; Blokesch, Melanie

    2016-01-01

    Vibrio cholerae is a human pathogen and the causative agent of cholera. The persistence of this bacterium in aquatic environments is a key epidemiological concern, as cholera is transmitted through contaminated water. Predatory protists, such as amoebae, are major regulators of bacterial populations in such environments. Therefore, we investigated the interaction between V. cholerae and the amoeba Acanthamoeba castellanii at the single-cell level. We observed that V. cholerae can resist intracellular killing. The non-digested bacteria were either released or, alternatively, established a replication niche within the contractile vacuole of A. castellanii. V. cholerae was maintained within this compartment even upon encystment. The pathogen ultimately returned to its aquatic habitat through lysis of A. castellanii, a process that was dependent on the production of extracellular polysaccharide by the pathogen. This study reinforces the concept that V. cholerae is a facultative intracellular bacterium and describes a new host–pathogen interaction. PMID:26394005

  16. Isolation of two strains of Acanthamoeba castellanii from human tissue and their pathogenicity and isoenzyme profiles.

    PubMed Central

    Visvesvara, G S; Mirra, S S; Brandt, F H; Moss, D M; Mathews, H M; Martinez, A J

    1983-01-01

    Two strains of amoebae, one (CDC:0180:1) from the lung tissue of a patient who died of granulomatous amoebic encephalitis and the other (CDC:0179:1) from the debrided tissue of a mandibular autograft, were isolated and identified as Acanthamoeba castellanii based on the morphological and immunofluorescent staining characteristics of the trophozoites and cysts. Both strains of amoebae caused cytopathic effects in mammalian cell cultures and destroyed the cell sheet. However, only the CDC:0180:1 strain, on intranasal instillation into mice, produced the disease manifested by ruffled fur and aimless wandering, followed by coma and death within 30 days. The CDC:0180:1 strain also differed consistently from CDC:0179:1 and another nonpathogenic A. castellanii strain (ATCC 30,011) in isoenzyme makeup, a dissimilarity which probably reflects its pathogenic potential. Images PMID:6655045

  17. Evaluation of the activity of new cationic carbosilane dendrimers on trophozoites and cysts of Acanthamoeba polyphaga.

    PubMed

    Heredero-Bermejo, Irene; Copa-Patiño, Jose Luis; Soliveri, Juan; Fuentes-Paniagua, Elena; de la Mata, Francisco Javier; Gomez, Rafael; Perez-Serrano, Jorge

    2015-02-01

    Dendrimers are repetitively branched molecules with a broad spectrum of applications, mainly for their antimicrobial properties and as nanocarriers for other molecules. Recently, our research group have synthesized and studied their activity against Acanthamoeba sp., causative agent of a severe ocular disease in humans: Acanthamoeba keratitis. New cationic carbosilane dendrimers were tested against the protozoa forms at different concentrations and for different incubation times. Trophozoite viability was determined by manual counting and cyst viability by observing excystment in microplates with fresh culture medium. Cytotoxicity was checked on HeLa cells using the microculture tetrazolium assay. Alterations were observed by optical microscopy and by flow cytometry staining with propidium iodide. Six out of the 18 dendrimers tested were non-cytotoxic and effective against the trophozoite form, having one of them (dendrimer 14 with an IC50 of 2.4 + 0.1 mg/L) a similar activity to chlorhexidine digluconate (IC50 1.7 + 0.1 mg/L). This dendrimer has a polyphenoxo core and a sulphur atom close to the six -NH3+ terminal groups. On the other hand, only two dendrimers showed some effect against cysts (dendrimers 14 and 17). However, their minimum cysticidal concentrations were cytotoxic and less effective than the control drug. The alterations on the amoeba morphology produced by the treatment with dendrimers were size reduction, increased complexity, loss of acanthopodia and cell membrane disruption. In conclusion, these results suggest that some dendrimers may be studied in animal models to test their effect and that new dendrimers with similar features should be synthesized. PMID:25358240

  18. Amebicidal activity of the essential oils of Lippia spp. (Verbenaceae) against Acanthamoeba polyphaga trophozoites.

    PubMed

    Santos, Israel Gomes de Amorim; Scher, Ricardo; Rott, Marilise Brittes; Menezes, Leociley Rocha; Costa, Emmanoel Vilaça; Cavalcanti, Sócrates Cabral de Holanda; Blank, Arie Fitzgerald; Aguiar, Jaciana dos Santos; da Silva, Teresinha Gonçalves; Dolabella, Silvio Santana

    2016-02-01

    Amoebic keratitis and granulomatous amoebic encephalitis are caused by some strains of free-living amoebae of the genus Acanthamoeba. In the case of keratitis, one of the greatest problems is the disease recurrence due to the resistance of parasites, especially the cystic forms, to the drugs that are currently used. Some essential oils of plants have been used as potential active agents against this protist. Thus, the aim of this study was to determine the amebicidal activity of essential oils from plants of the genus Lippia against Acanthamoeba polyphaga trophozoites. To that end, 8 × 10(4) trophozoites were exposed for 24 h to increasing concentrations of essential oils from Lippia sidoides, Lippia gracilis, Lippia alba, and Lippia pedunculosa and to their major compounds rotundifolone, carvone, and carvacrol. Nearly all concentrations of oils and compounds showed amebicidal activity. The IC50 values for L. sidoides, L. gracilis L. alba, and L. pedunculosa were found to be 18.19, 10.08, 31.79, and 71.47 μg/mL, respectively. Rotundifolone, carvacrol, and carvone were determined as the major compounds showing IC50 of 18.98, 24.74, and 43.62 μg/mL, respectively. With the exception of oil from L. alba, the other oils evaluated showed low cytotoxicity in the NCI-H292 cell line. Given these results, the oils investigated here are promising sources of compounds for the development of complementary therapy against amoebic keratitis and granulomatous amoebic encephalitis and can also be incorporated into cleaning solutions to increase their amebicidal efficiency.

  19. Public health implications of Acanthamoeba and multiple potential opportunistic pathogens in roof-harvested rainwater tanks.

    PubMed

    Hamilton, K A; Ahmed, W; Palmer, A; Sidhu, J P S; Hodgers, L; Toze, S; Haas, C N

    2016-10-01

    A study of six potential opportunistic pathogens (Acanthamoeba spp., Legionella spp., Legionella longbeachae, Pseudomonas aeruginosa, Mycobacterium avium and Mycobacterium intracellulare) and an accidental human pathogen (Legionella pneumophila) in 134 roof-harvested rainwater (RHRW) tank samples was conducted using quantitative PCR (qPCR). All five opportunistic pathogens and accidental pathogen L. pneumophila were detected in rainwater tanks except Legionella longbeachae. Concentrations ranged up to 3.1×10(6) gene copies per L rainwater for Legionella spp., 9.6×10(5) gene copies per L for P. aeruginosa, 6.8×10(5) gene copies per L for M. intracellulare, 6.6×10(5) gene copies per L for Acanthamoeba spp., 1.1×10(5) gene copies per L for M. avium, and 9.8×10(3) gene copies per L for L. pneumophila. Among the organisms tested, Legionella spp. (99% tanks) were the most prevalent followed by M. intracellulare (78%). A survey of tank-owners provided data on rainwater end-uses. Fecal indicator bacteria (FIB) Escherichia coli and Enterococcus spp. were enumerated using culture-based methods, and assessed for correlations with opportunistic pathogens and L. pneumophila tested in this study. Opportunistic pathogens did not correlate well with FIB except E. coli vs. Legionella spp. (tau=0.151, P=0.009) and E. coli vs. M. intracellulare (tau=0.14, P=0.015). However, M. avium weakly correlated with both L. pneumophila (Kendall's tau=0.017, P=0.006) and M. intracellulare (tau=0.088, P=0.027), and Legionella spp. also weakly correlated with M. intracellulare (tau=0.128, P=0.028). The presence of these potential opportunistic pathogens in tank water may present health risks from both the potable and non-potable uses documented from the current survey data. PMID:27336236

  20. Amino Acid Uptake and Metabolism of Legionella pneumophila Hosted by Acanthamoeba castellanii*

    PubMed Central

    Schunder, Eva; Gillmaier, Nadine; Kutzner, Erika; Herrmann, Vroni; Lautner, Monika; Heuner, Klaus; Eisenreich, Wolfgang

    2014-01-01

    Legionella pneumophila survives and replicates within a Legionella-containing vacuole (LCV) of amoebae and macrophages. Less is known about the carbon metabolism of the bacteria within the LCV. We have now analyzed the transfer and usage of amino acids from the natural host organism Acanthamoeba castellanii to Legionella pneumophila under in vivo (LCV) conditions. For this purpose, A. castellanii was 13C-labeled by incubation in buffer containing [U-13C6]glucose. Subsequently, these 13C-prelabeled amoebae were infected with L. pneumophila wild type or some mutants defective in putative key enzymes or regulators of carbon metabolism. 13C-Isotopologue compositions of amino acids from bacterial and amoebal proteins were then determined by mass spectrometry. In a comparative approach, the profiles documented the efficient uptake of Acanthamoeba amino acids into the LCV and further into L. pneumophila where they served as precursors for bacterial protein biosynthesis. More specifically, A. castellanii synthesized from exogenous [U-13C6]glucose unique isotopologue mixtures of several amino acids including Phe and Tyr, which were also observed in the same amino acids from LCV-grown L. pneumophila. Minor but significant differences were only detected in the isotopologue profiles of Ala, Asp, and Glu from the amoebal or bacterial protein fractions, respectively, indicating partial de novo synthesis of these amino acids by L. pneumophila. The similar isotopologue patterns in amino acids from L. pneumophila wild type and the mutants under study reflected the robustness of amino acid usage in the LCV of A. castellannii. PMID:24904060

  1. Resistance of Acanthamoeba Cysts to Disinfection Treatments Used in Health Care Settings▿

    PubMed Central

    Coulon, Céline; Collignon, Anne; McDonnell, Gerald; Thomas, Vincent

    2010-01-01

    Free-living amoebae that belong to the genus Acanthamoeba are widespread in the environment, including water. They are responsible for human infections and can host pathogenic microorganisms. Under unfavorable conditions, they form cysts with high levels of resistance to disinfection methods, thus potentially representing a threat to public health. In the present study we evaluated the efficacies of various biocides against trophozoites and cysts of several Acanthamoeba strains. We demonstrated that disinfectant efficacy varied depending on the strains tested, with environmental strains demonstrating greater resistance than collection strains. Trophozoites were inactivated by all treatments except those using glutaraldehyde as an active compound: for these treatments, we observed resistance even after 30 min exposure. Cysts resisted many treatments, including certain conditions with glutaraldehyde and other biocides. Moist heat at 55°C was not efficient against cysts, whereas exposure at 65°C was. Several chemical formulations containing peracetic acid, hydrogen peroxide, or ortho-phthalaldehyde presented greater efficacy than glutaraldehyde, as did ethanol and sodium hypochlorite; however, some of these treatments required relatively long incubation times to achieve cyst inactivation. Amoebal cysts can be highly resistant to some high-level disinfectants, which has implications for clinical practice. These results highlight the need to consider the effective disinfection of protozoa in their vegetative and resistant forms due to their intrinsic resistance. This is important not only to prevent the transmission of protozoa themselves but also due to the risks associated with a range of microbial pathogens that are found to be associated intracellularly with these microorganisms. PMID:20519477

  2. Public health implications of Acanthamoeba and multiple potential opportunistic pathogens in roof-harvested rainwater tanks.

    PubMed

    Hamilton, K A; Ahmed, W; Palmer, A; Sidhu, J P S; Hodgers, L; Toze, S; Haas, C N

    2016-10-01

    A study of six potential opportunistic pathogens (Acanthamoeba spp., Legionella spp., Legionella longbeachae, Pseudomonas aeruginosa, Mycobacterium avium and Mycobacterium intracellulare) and an accidental human pathogen (Legionella pneumophila) in 134 roof-harvested rainwater (RHRW) tank samples was conducted using quantitative PCR (qPCR). All five opportunistic pathogens and accidental pathogen L. pneumophila were detected in rainwater tanks except Legionella longbeachae. Concentrations ranged up to 3.1×10(6) gene copies per L rainwater for Legionella spp., 9.6×10(5) gene copies per L for P. aeruginosa, 6.8×10(5) gene copies per L for M. intracellulare, 6.6×10(5) gene copies per L for Acanthamoeba spp., 1.1×10(5) gene copies per L for M. avium, and 9.8×10(3) gene copies per L for L. pneumophila. Among the organisms tested, Legionella spp. (99% tanks) were the most prevalent followed by M. intracellulare (78%). A survey of tank-owners provided data on rainwater end-uses. Fecal indicator bacteria (FIB) Escherichia coli and Enterococcus spp. were enumerated using culture-based methods, and assessed for correlations with opportunistic pathogens and L. pneumophila tested in this study. Opportunistic pathogens did not correlate well with FIB except E. coli vs. Legionella spp. (tau=0.151, P=0.009) and E. coli vs. M. intracellulare (tau=0.14, P=0.015). However, M. avium weakly correlated with both L. pneumophila (Kendall's tau=0.017, P=0.006) and M. intracellulare (tau=0.088, P=0.027), and Legionella spp. also weakly correlated with M. intracellulare (tau=0.128, P=0.028). The presence of these potential opportunistic pathogens in tank water may present health risks from both the potable and non-potable uses documented from the current survey data.

  3. Analysis of focusing error signals by differential astigmatic method under off-center tracking in the land-groove-type optical disk

    NASA Astrophysics Data System (ADS)

    Shinoda, Masahisa; Nakatani, Hidehiko

    2015-04-01

    We theoretically calculate the behavior of the focusing error signal in the land-groove-type optical disk when the objective lens traverses on out of the radius of the optical disk. The differential astigmatic method is employed instead of the conventional astigmatic method for generating the focusing error signals. The signal behaviors are compared and analyzed in terms of the gain difference of the slope sensitivity of the focusing error signals from the land and the groove. In our calculation, the format of digital versatile disc-random access memory (DVD-RAM) is adopted as the land-groove-type optical disk model, and advantageous conditions for suppressing the gain difference are investigated. The calculation method and results described in this paper will be reflected in the next generation land-groove-type optical disks.

  4. Efficacy of Wavefront-guided Photorefractive Keratectomy with Iris Registration for Management of Moderate to High Astigmatism by Advanced Personalized Treatment Nomogram

    PubMed Central

    Mohammadpour, Mehrdad; Hashemi, Hassan; Jabbarvand, Mahmoud; Rahmatnejad, Kamran; Sabet, Fatemeh Alsadat

    2016-01-01

    Purpose: To evaluate the efficacy of photorefractive keratectomy (PRK) using the advanced personalized treatment (APT) nomogram for correction of moderate to high astigmatism. Methods: This prospective interventional case series included 60 consecutive eyes of 30 patients undergoing wavefront-guided PRK (Zyoptix 217 Z100 excimer laser, Bausch & Lomb, Munich, Germany) using the APT nomogram and iris registration for myopic astigmatism. Mitomycin-C was applied intraoperatively in all eyes. Ophthalmic examination was performed preoperatively and 1, 3 and 6 months postoperatively. Results: Preoperatively, mean sphere was -1.68 ± 2.08 diopters (D), mean refractive astigmatism was -3.04 ± 1.05 D and mean spherical equivalent (SE) was -3.12 ± 1.77 D. Six months postoperatively, mean sphere was + 0.60 ± 0.64 D (P < 0.005), mean cylinder was -0.43 ± 0.46 D (P < 0.005) and mean SE was + 0.28 ± 0.48 D (P < 0.005). Hyperopic overcorrection (≥ +1.0 D) occurred in 3 (5%) eyes. Postoperatively, root mean square (RMS) of higher order aberrations (HOAs) was significantly increased (P = 0.041). RMS of spherical aberration (Z [4, 0]) showed no significant change after surgery (P = 0.972). Conclusion: Considering the acceptable residual refractive error, low rate of hyperopic overcorrection, acceptable uncorrected visual acuity, and low risk of postoperative corneal haze, PRK using the APT nomogram with iris registration and mitomycin-C use is a safe and effective modality for treatment of moderate to high astigmatism. PMID:27413491

  5. Single-Step Transepithelial PRK vs Alcohol-Assisted PRK in Myopia and Compound Myopic Astigmatism Correction.

    PubMed

    Kaluzny, Bartlomiej J; Cieslinska, Iwona; Mosquera, Samuel A; Verma, Shwetabh

    2016-02-01

    Transepithelial photorefractive keratectomy (tPRK), where both the epithelium and stroma are removed in a single-step, is a relatively new procedure of laser refractive error correction. This study compares the 3-month results of myopia and compound myopic astigmatism correction by tPRK or conventional alcohol-assisted PRK (aaPRK).This prospective, nonrandomized, case-control study recruited 148 consecutive patients; 93 underwent tPRK (173 eyes) and 55 aaPRK (103 eyes). Refractive results, predictability, safety, and efficacy were evaluated during the 3-month follow-up. The main outcome measures were uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), and mean refractive spherical equivalent (MRSE).Mean preoperative MRSE was -4.30 ± 1.72 D and -4.33 ± 1.96 D, respectively (P = 0.87). The 3-month follow-up rate was 82.1% in the tPRK group (n = 145) and 86.4% in aaPRK group (n = 90), P = 0.81. Postoperative UDVA was 20/20 or better in 97% and 94% of eyes, respectively (P = 0.45). In the tPRK and aaPRK groups, respectively, 13% and 21% of eyes lost 1 line of CDVA, and 30% and 31% gained 1 or 2 lines (P = 0.48). Mean postoperative MRSE was -0.14 ± 0.26 D in the tPRK group and -0.12 ± 0.20 D in the aaPRK group (P = 0.9). The correlation between attempted versus achieved MRSE was equally high in both groups.Single-step transepithelial PRK and conventional PRK provide very similar results 3 months postoperatively. These procedures are predictable, effective, and safe for correction of myopia and compound myopic astigmatism.

  6. Fluorescent Oligonucleotide Probes for Clinical and Environmental Detection of Acanthamoeba and the T4 18S rRNA Gene Sequence Type

    PubMed Central

    Stothard, Diane R.; Hay, John; Schroeder-Diedrich, Jill M.; Seal, David V.; Byers, Thomas J.

    1999-01-01

    The first genus- and subgenus-specific fluorescent oligonucleotide probes for in situ staining of Acanthamoeba are described. Sequences of these phylogeny-based probes complement the 18S rRNA and the gene encoding it (18S rDNA). The genus-specific probe (GSP) is a fluorescein-labeled 22-mer specific for Acanthamoeba as shown here by its hybridization to growing trophozoites of all 12 known Acanthamoeba 18S rDNA sequence types and by its failure to hybridize with amoebae of two other genera (Hartmannella vermiformis and Balamuthia mandrillaris), two human cell lines, and two bacteria (Pseudomonas aeruginosa and Escherichia coli). The sequence type T4-specific probe (ST4P) is a rhodamine-labeled 30-mer specific for Acanthamoeba 18S rDNA sequence type T4, as shown here in hybridization tests with trophozoites of all 12 sequence types. T4 is the subgenus group associated most closely with Acanthamoeba keratitis (AK). GSP also was tested with corneal scrapings from 17 patients with a high index of clinical suspicion of AK plus 5 patient controls. GSP stained both trophozoites and cysts, although nonspecific cyst wall autofluorescence also was observed. Results could be obtained with GSP in 1 to 2 days, and based on results from cell culture tests, the probe correctly detected the presence or absence of Acanthamoeba in 21 of 24 specimens from the 22 patients. The use of GSP with cultured trophozoites and cysts from corneal scrapings has illustrated the suitability of using fluorescent oligonucleotide probes for identification of the genus Acanthamoeba in both environmental and clinical samples. In addition, the use of ST4P with cultured amoebae has indicated the potential of oligonucleotide probes for use in subgenus classification. PMID:10405422

  7. Influence of temperature, oxygen and bacterial strain identity on the association of Campylobacter jejuni with Acanthamoeba castellanii.

    PubMed

    Baré, Julie; Sabbe, Koen; Huws, Sharon; Vercauteren, Dries; Braeckmans, Kevin; van Gremberghe, Ineke; Favoreel, Herman; Houf, Kurt

    2010-11-01

    Campylobacteriosis is the most frequently reported foodborne disease in the industrialized world, mainly through consumption of contaminated chicken meat. To date, no information is available on the primary infection sources of poultry. In this study, the ability of five Campylobacter jejuni strains with different invasion potential towards Caco-2 cells to survive and replicate in the protozoan Acanthamoeba castellanii was tested under simulated in situ conditions (i.e. chicken broiler houses). Results indicate that environmental conditions play a crucial role in C. jejuni-A. castellanii interactions. Co-culture in general did not result in an increase of either bacteria or amoebae. However, co-culture with Acanthamoeba did result in a delayed decline and an increased long-term survival of Campylobacter. Bacterial strain-specific effects were observed, with higher survival rates for low-invasive strains. The presence of C. jejuni in general did not affect A. castellanii viability, except at 37 °C under microaerobic conditions, where the presence of the reference and low-invasive Campylobacter strains resulted in a significant decline in amoebal viability. Confocal laser scanning microscopy revealed that intra-amoebal campylobacters were not always colocated with acidic organelles, suggesting potential bacterial interference with digestive processes. As Acanthamoeba enhances the persistence of C. jejuni, the presence of the amoeba in broiler house environments may have important implications for the ecology and epidemiology of this food pathogen. PMID:20722733

  8. Direct photoaffinity labeling by nucleotides of the apparent catalytic site on the heavy chains of smooth muscle and Acanthamoeba myosins

    SciTech Connect

    Maruta, H.; Korn, E.D.

    1981-01-10

    The heavy chains of Acanthamoeba myosins, IA, IB and II, turkey gizzard myosin, and rabbit skeletal muscle myosin subfragment-1 were specifically labeled by radioactive ATP, ADP, and UTP, each of which is a substrate or product of myosin ATPase activity, when irradiated with uv light at 0/sup 0/C. With UTP, as much as 0.45 mol/mol of Acanthamoeba myosin IA heavy chain and 1 mol/mol of turkey gizzard myosin heavy chain was incorporated. Evidence that the ligands were associated with the catalytic site included the observations that reaction occurred only with nucleotides that are substrates or products of the ATPase activity; that the reaction was blocked by pyrophosphate which is an inhibitor of the ATPase activity; that ATP was bound as ADP; and that label was probably restricted to a single peptide following limited subtilisin proteolysis of labeled Acanthamoeba myosin IA heavy chain and extensive cleavage with CNBr and trypsin of labeled turkey gizzard myosin heavy chain.

  9. A fatal case of meningoencephalitis due to a free-living amoeba of uncertain identity--probably acanthamoeba sp.

    PubMed

    Carter, R F; Cullity, G J; Ojeda, V J; Silberstein, P; Willaert, E

    1981-01-01

    There are 2 main types of meningoencephalitis caused by free-living amoebae. The first is a well-defined acutely fatal disease resembling fulminating bacterial meningitis. It is caused by the single species Naegleria fowleri. The second is a more poorly defined disease that runs a subacute or chronic course and is characterized by focal granulomatous lesions in the brain. The causative organisms are probably Acanthamoeba sp. in most cases, but it is possible that other genera may be involved. The first case of the subacute form of the disease to be recognized in Australia is described. A 2 1/2-yr-old, previously well girl presented with ataxia and lower motor neurone paralyses. The cerebrospinal fluid was pleocytic and she was thought to be suffering from a relatively minor viral brain-stem encephalitis. Her symptoms persisted in a peculiarly fluctuating way for 30 d when she suddenly collapsed and died from an intracranial haemorrhage. Necropsy showed focal granulomatous lesions associated with necrotizing vasculitis in the basal regions of the brain. The lesions contained well preserved free-living amoebae which were morphologically different from N. fowleri and most closely resembled Acanthamoeba sp. The ultrastructure of the organisms was particularly well preserved and is described in some detail. Immunohistological studies also excluded N. fowleri but were inconclusive for Acanthamoeba or other genera of free-living amoebae. Difficulties with the diagnosis and treatment of this disease are discussed and some practical suggestions are made. PMID:6261208

  10. Conditioned medium from stimulated mononuclear leukocytes augments human neutrophil-mediated killing of a virulent Acanthamoeba sp.

    PubMed Central

    Ferrante, A; Abell, T J

    1986-01-01

    Human neutrophils in the presence of serum containing anti-amoeba antibody either lacked amoebicidal activity or were poorly amoebicidal for Acanthamoeba culbertsoni. In contrast, neutrophils preexposed for 1 h to supernatants from human peripheral blood mononuclear leukocytes (MNLs) stimulated with phytohemagglutinin demonstrated significant amoeba killing in the presence of serum containing anti-acanthamoeba antibodies. Supernatant from MNL cultured in the absence of phytohemagglutinin were not effective in stimulating significant activity in the neutrophils. Serum containing antibody promoted the adherence of many neutrophils to one amoeba. There was no significant difference between the ability of neutrophils treated with supernatants from stimulated MNLs (stimulated conditioned medium [sCM]) and supernatants from nonstimulated MNLs (nonstimulated conditioned medium [nsCM]) in their binding to acanthamoeba. The effects of sCM on neutrophils was a general phenomenon. For example, the sCM but not the nsCM enhanced the antibody-dependent neutrophil-mediated cytotoxicity against three tumor targets (K562 erythroid myeloid leukemia cell line, B16 melanoma, and P815 (DBA/2 mastocytoma). Furthermore, the sCM but not the nsCM increased the bactericidal (against Staphylococcus aureus and Streptococcus pneumoniae) and fungicidal (against Torulopsis glabrata) activity of the neutrophil. The sCM but not the nsCM contained activities which inhibited neutrophil migration and stimulated a respiratory burst in these leukocytes. These results suggest that the neutrophil antimicrobial power can be increased by exposing the leukocytes to MNL mediators. Images PMID:3943902

  11. [Acanthamoeba, naturally intracellularly infected with Pseudomonas aeruginosa, after their isolation from a microbiologically contaminated drinking water system in a hospital].

    PubMed

    Michel, R; Burghardt, H; Bergmann, H

    1995-03-01

    The drinking water system of a new hospital building that was highly contaminated with bacteria before opening was investigated too for the prevalence of small free living amoebae. Germ counts resulted in > 100 CFU/ml in 100% of the cold water samples, that showed also growth of P. aeruginosa, whereas E. coli and coliforme bacteria could not be identified. The investigation of 37 water samples for protozoa revealed growth of small freeliving amoebae in 20 samples (54%) belonging to 10 species of the genus Acanthamoeba, Naegleria, Hartmannella, Echinamoeba among others. In addition 2 Ciliate- and 2 Microflagellate-species could be observed. While all Naegleria strains isolated belonged to the N. gruberi-complex two of 16 Acanthamoeba-isolates proved to be pathogenic for laboratory mice. From 7 watersamples positive with P. aeruginosa 5 Acanthamoeba- and 2 Echinamoeba strains could be isolated which revealed intracellular multiplication of P. aeruginosa. Because of their well known resistances against chlorine, the amoebae and their cysts are considered to be vectors for these intracellular bacteria. A complete sanitation of the incriminated drinking water system was accomplished by combined chemical and thermic disinfection measures.

  12. Sequences, structural models, and cellular localization of the actin- related proteins Arp2 and Arp3 from Acanthamoeba

    PubMed Central

    1995-01-01

    We cloned and sequenced the two actin-related proteins (Arps) present in the profilin-binding complex of Acanthamoeba (Machesky, L. M., S. J. Atkinson, C. Ampe, J. Vandekerckhove, and T. D. Pollard. 1994, J. Cell Biol. 127:107-115). The sequence of Arp2 is more similar to other Arp2s than to actin, while the sequence of Arp3 is more similar to other Arp3s than to actin. Phylogenetic analysis of all known Arps demonstrates that most group into three major families, which are likely to be shared across all eukaryotic phyla. Together with conventional actins, the Arps form a larger family distinct from structurally related ATPases such as Hsp70's and sugar kinases. Atomic models of the Arps based on their sequences and the structure of actin provide some clues about function. Both Arps have atoms appropriately placed to bind ATP and divalent cation. Arp2, but not Arp3, has a conserved profilin-binding site. Neither Arp has the residues required to copolymerize with actin, but an Arp heterodimer present in the profilin-binding complex might serve as a pointed end nucleus for actin polymerization. Both Acanthamoeba Arps are soluble in cell homogenates, and both are concentrated in the cortex of Acanthamoeba. The cellular concentrations are 1.9 microM Arp2 and 5.1 microM Arp3, substoichiometric to actin (200 microM) but comparable to many actin- binding proteins. PMID:7593166

  13. Hard X-ray Spectroscopy and Imaging by a Reflection Zone Plate in the Presence of Astigmatism

    SciTech Connect

    Braig, Christoph; Lochel, Heike; Hafner, Aljosa; Firsov, Alexander; Rehanek, Jens; Brzhezinskaya, Maria; Wojcik, Michael; Macrander, Albert; Assoufid, Lahsen; Erko, Alexei

    2016-01-01

    The feasibility of an off-axis x-ray reflection zone plate to perform wavelength-dispersive spectroscopy, on-axis point focusing, and two-dimensional imaging is demonstrated by means of one and the same diffractive optical element (DOE) at a synchrotron radiation facility. The resolving power varies between 3×101 and 4×102 in the range of 7.6 keV to 9.0 keV, with its maximum at the design energy of 8.3 keV. This result is verified using an adjustable entrance slit, by which horizontal (H) and vertical (V) focusing to 0.85 μm(H) and 1.29 μm(V) is obtained near the sagittal focal plane of the astigmatic configuration. An angular and axial scan proves an accessible field of view of at least 0.6 arcmin × 0.8 arcmin and a focal depth of ±0.86 mm. Supported by the grating efficiency of around 17.5% and a very short pulse elongation, future precision x-ray fluorescence and absorption studies of transition metals at their K-edge on an ultrashort timescale could benefit from our findings.

  14. Q-value customized ablation (custom-Q) versus wavefront optimized ablation for primary myopia and myopic astigmatism.

    PubMed

    Tawfik, Ahmed; Eid, Ahmed Mostafa; Hasanen, Rabei; Moftah, Ismail A N

    2014-04-01

    Comparison between treatment with wavefront optimized and custom-Q laser-assisted in situ keratomileusis (LASIK) ablations. Our study included 400 eyes of 200 patients divided into two equal groups. All patients were treated for myopia and myopic astigmatism with LASIK. The first group was treated with wavefront optimized ablation and the second group with custom-Q ablation. They were examined preoperatively and postoperatively to assess asphericity, image quality, and other classical outcome parameters. The wavefront optimized ablation group comprised 200 eyes with a mean spherical equivalent refraction (SE) of -5.2188 diopters (D) (range: -1.15 to -10.50 D); the mean Q-value changed from 0.30 preoperatively to 0.06 postoperatively. The custom-Q ablation group also comprised 200 eyes with a mean SE of -5.1575 D (range: -1.35 to -9.00 D); the mean Q-value changed from 0.32 preoperatively to 0.03 postoperatively. A statistically significant difference in postoperative change in Q-values (P = 0.02) and in postoperative visual acuity (P = 0.42) between the two groups was noted. There was no difference between the two groups regarding refractive correction. There was a marginally significant change in BSCVA (best spectacle-corrected visual acuity) between the two groups, and less impairment in the corneal asphericity in the custom-Q group.

  15. Genome-wide association study for refractive astigmatism reveals genetic co-determination with spherical equivalent refractive error: the CREAM consortium.

    PubMed

    Li, Qing; Wojciechowski, Robert; Simpson, Claire L; Hysi, Pirro G; Verhoeven, Virginie J M; Ikram, Mohammad Kamran; Höhn, René; Vitart, Veronique; Hewitt, Alex W; Oexle, Konrad; Mäkelä, Kari-Matti; MacGregor, Stuart; Pirastu, Mario; Fan, Qiao; Cheng, Ching-Yu; St Pourcain, Beaté; McMahon, George; Kemp, John P; Northstone, Kate; Rahi, Jugnoo S; Cumberland, Phillippa M; Martin, Nicholas G; Sanfilippo, Paul G; Lu, Yi; Wang, Ya Xing; Hayward, Caroline; Polašek, Ozren; Campbell, Harry; Bencic, Goran; Wright, Alan F; Wedenoja, Juho; Zeller, Tanja; Schillert, Arne; Mirshahi, Alireza; Lackner, Karl; Yip, Shea Ping; Yap, Maurice K H; Ried, Janina S; Gieger, Christian; Murgia, Federico; Wilson, James F; Fleck, Brian; Yazar, Seyhan; Vingerling, Johannes R; Hofman, Albert; Uitterlinden, André; Rivadeneira, Fernando; Amin, Najaf; Karssen, Lennart; Oostra, Ben A; Zhou, Xin; Teo, Yik-Ying; Tai, E Shyong; Vithana, Eranga; Barathi, Veluchamy; Zheng, Yingfeng; Siantar, Rosalynn Grace; Neelam, Kumari; Shin, Youchan; Lam, Janice; Yonova-Doing, Ekaterina; Venturini, Cristina; Hosseini, S Mohsen; Wong, Hoi-Suen; Lehtimäki, Terho; Kähönen, Mika; Raitakari, Olli; Timpson, Nicholas J; Evans, David M; Khor, Chiea-Chuen; Aung, Tin; Young, Terri L; Mitchell, Paul; Klein, Barbara; van Duijn, Cornelia M; Meitinger, Thomas; Jonas, Jost B; Baird, Paul N; Mackey, David A; Wong, Tien Yin; Saw, Seang-Mei; Pärssinen, Olavi; Stambolian, Dwight; Hammond, Christopher J; Klaver, Caroline C W; Williams, Cathy; Paterson, Andrew D; Bailey-Wilson, Joan E; Guggenheim, Jeremy A

    2015-02-01

    To identify genetic variants associated with refractive astigmatism in the general population, meta-analyses of genome-wide association studies were performed for: White Europeans aged at least 25 years (20 cohorts, N = 31,968); Asian subjects aged at least 25 years (7 cohorts, N = 9,295); White Europeans aged <25 years (4 cohorts, N = 5,640); and all independent individuals from the above three samples combined with a sample of Chinese subjects aged <25 years (N = 45,931). Participants were classified as cases with refractive astigmatism if the average cylinder power in their two eyes was at least 1.00 diopter and as controls otherwise. Genome-wide association analysis was carried out for each cohort separately using logistic regression. Meta-analysis was conducted using a fixed effects model. In the older European group the most strongly associated marker was downstream of the neurexin-1 (NRXN1) gene (rs1401327, P = 3.92E-8). No other region reached genome-wide significance, and association signals were lower for the younger European group and Asian group. In the meta-analysis of all cohorts, no marker reached genome-wide significance: The most strongly associated regions were, NRXN1 (rs1401327, P = 2.93E-07), TOX (rs7823467, P = 3.47E-07) and LINC00340 (rs12212674, P = 1.49E-06). For 34 markers identified in prior GWAS for spherical equivalent refractive error, the beta coefficients for genotype versus spherical equivalent, and genotype versus refractive astigmatism, were highly correlated (r = -0.59, P = 2.10E-04). This work revealed no consistent or strong genetic signals for refractive astigmatism; however, the TOX gene region previously identified in GWAS for spherical equivalent refractive error was the second most strongly associated region. Analysis of additional markers provided evidence supporting widespread genetic co-susceptibility for spherical and astigmatic refractive errors.

  16. Comparison of specific activity and cytopathic effects of purified 33 kDa serine proteinase from Acanthamoeba strains with different degree of virulence

    PubMed Central

    Kim, Won-Tae; Kong, Hyun-Hee; Ha, Young-Ran; Hong, Yeon-Chul; Jeong, Hae Jin; Yu, Hak Sun

    2006-01-01

    The pathogenic mechanism of granulomatous amebic encephalitis (GAE) and amebic keratitis (AK) by Acanthamoeba has yet to be clarified. Protease has been recognized to play an important role in the pathogenesis of GAE and AK. In the present study, we have compared specific activity and cytopathic effects (CPE) of purified 33 kDa serine proteinases from Acanthamoeba strains with different degree of virulence (A. healyi OC-3A, A. lugdunensis KA/E2, and A. castellanii Neff). Trophozoites of the 3 strains revealed different degrees of CPE on human corneal epithelial (HCE) cells. The effect was remarkably reduced by adding phenylmethylsulfonylfluoride (PMSF), a serine proteinase inhibitor. This result indicated that PMSF-susceptible proteinase is the main component causing cytopathy to HCE cells by Acanthamoeba. The purified 33 kDa serine proteinase showed strong activity toward HCE cells and extracellular matrix proteins. The purified proteinase from OC-3A, the most virulent strain, demonstrated the highest enzyme activity compared to KA/E2, an ocular isolate, and Neff, a soil isolate. Polyclonal antibodies against the purified 33 kDa serine proteinase inhibit almost completely the proteolytic activity of culture supernatant of Acanthamoeba. In line with these results, the 33 kDa serine proteinase is suggested to play an important role in pathogenesis and to be the main component of virulence factor of Acanthamoeba. PMID:17170574

  17. Ultra-high-speed 3D astigmatic particle tracking velocimetry: application to particle-laden supersonic impinging jets

    NASA Astrophysics Data System (ADS)

    Buchmann, N. A.; Cierpka, C.; Kähler, C. J.; Soria, J.

    2014-11-01

    The paper demonstrates ultra-high-speed three-component, three-dimensional (3C3D) velocity measurements of micron-sized particles suspended in a supersonic impinging jet flow. Understanding the dynamics of individual particles in such flows is important for the design of particle impactors for drug delivery or cold gas dynamic spray processing. The underexpanded jet flow is produced via a converging nozzle, and micron-sized particles ( d p = 110 μm) are introduced into the gas flow. The supersonic jet impinges onto a flat surface, and the particle impact velocity and particle impact angle are studied for a range of flow conditions and impingement distances. The imaging system consists of an ultra-high-speed digital camera (Shimadzu HPV-1) capable of recording rates of up to 1 Mfps. Astigmatism particle tracking velocimetry (APTV) is used to measure the 3D particle position (Cierpka et al., Meas Sci Technol 21(045401):13, 2010) by coding the particle depth location in the 2D images by adding a cylindrical lens to the high-speed imaging system. Based on the reconstructed 3D particle positions, the particle trajectories are obtained via a higher-order tracking scheme that takes advantage of the high temporal resolution to increase robustness and accuracy of the measurement. It is shown that the particle velocity and impingement angle are affected by the gas flow in a manner depending on the nozzle pressure ratio and stand-off distance where higher pressure ratios and stand-off distances lead to higher impact velocities and larger impact angles.

  18. Atomic force microscopic imaging of Acanthamoeba castellanii and Balamuthia mandrillaris trophozoites and cysts.

    PubMed

    Aqeel, Yousuf; Siddiqui, Ruqaiyyah; Ateeq, Muhammad; Raza Shah, Muhammad; Kulsoom, Huma; Khan, Naveed Ahmed

    2015-01-01

    Light microscopy and electron microscopy have been successfully used in the study of microbes, as well as free-living protists. Unlike light microscopy, which enables us to observe living organisms or the electron microscope which provides a two-dimensional image, atomic force microscopy provides a three-dimensional surface profile. Here, we observed two free-living amoebae, Acanthamoeba castellanii and Balamuthia mandrillaris under the phase contrast inverted microscope, transmission electron microscope and atomic force microscope. Although light microscopy was of lower magnification, it revealed functional biology of live amoebae such as motility and osmoregulation using contractile vacuoles of the trophozoite stage, but it is of limited value in defining the cyst stage. In contrast, transmission electron microscopy showed significantly greater magnification and resolution to reveal the ultra-structural features of trophozoites and cysts including intracellular organelles and cyst wall characteristics but it only produced a snapshot in time of a dead amoeba cell. Atomic force microscopy produced three-dimensional images providing detailed topographic description of shape and surface, phase imaging measuring boundary stiffness, and amplitude measurements including width, height and length of A. castellanii and B. mandrillaris trophozoites and cysts. These results demonstrate the importance of the application of various microscopic methods in the biological and structural characterization of the whole cell, ultra-structural features, as well as surface components and cytoskeleton of protist pathogens.

  19. Co-incubation of Acanthamoeba castellanii with strains of Pseudomonas aeruginosa alters the survival of amoeba.

    PubMed

    Cengiz, A M; Harmis, N; Stapleton, F

    2000-06-01

    Enhanced survival of Acanthamoeba castellanii has previously been reported following co-incubation with a single strain of Pseudomonas aeruginosa. The aim of this study was to evaluate the impact of different strains of P. aeruginosa on amoebae survival. Four contact lens solutions were challenged with A. castellanii for between 6 and 24 h, and survival rates of amoeba were calculated. Subsequently, A. castellanii was co-incubated with different strains of P. aeruginosa (strain 6294, an invasive isolate; 6206, a cytotoxic isolate; and Paer 001, a null isolate). Differences in amoeba survival over time between solutions for each bacterial strain were analysed. Non-neutralized hydrogen peroxide was the most effective system against A. castellani at all time points (P<0.05). Survival rates were not different between multipurpose solutions and neutralized hydrogen peroxide. Co-incubation with P. aeruginosa altered amoeba survival, and maximum survival occurred in the presence of the invasive strain of P. aeruginosa. Enhanced amoeba survival may occur in the presence of certain strains of Gram-negative bacteria, and with certain types of contact lens disinfection systems.

  20. Acanthamoeba and other free-living amoebae in bat guano, an extreme habitat.

    PubMed

    Mulec, Janez; Dietersdorfer, Elisabeth; Üstüntürk-Onan, Miray; Walochnik, Julia

    2016-04-01

    Several representatives of the so-called free-living amoebae (FLA) are of medical relevance, not only as facultative pathogens but also as vehicles for pathogenic bacteria. Some FLA can survive and even grow under extreme environmental conditions. Bat guano is an exceptional habitat, the conditions becoming gradually more extreme with aging. In the current study, samples of bat guano of different ages from five caves in Slovenia were screened for the presence of FLA. FLA were isolated from almost all guano samples, including guano with a pH of 3.5. Only the two samples that had been drawn from >20-year-old guano were negative for FLA. Generally, FLA diversity correlated to high concentrations of cultivable bacteria (∼10(8) CFU/g) and fungi (∼10(5) CFU/g). Interestingly, the absence of FLA in seasoned guanos was mirrored by the presence of dictyostelid slime moulds. The isolated amoebae were identified as belonging to the genera Acanthamoeba, Copromyxa, Naegleria, Sappinia, Tetramitus, Thecamoeba, Vahlkampfia, Vannella and Vermamoeba. To the best of our knowledge, this is the first study on the diversity of FLA in guano.

  1. Transcription and processing of mitochondrial RNA in the human pathogen Acanthamoeba castellanii.

    PubMed

    Accari, Jessica; Barth, Christian

    2015-07-01

    The size, structure, gene content and organisation of mitochondrial genomes can be highly diverse especially amongst the protists. We investigated the transcription and processing of the mitochondrial genome of the opportunistic pathogen Acanthamoeba castellanii and here we present a detailed transcription map of the 41.6 kb genome that encodes 33 proteins, 16 tRNAs and 2 rRNAs. Northern hybridisation studies identified six major polycistronic transcripts, most of which are co-transcriptionally processed into smaller mono-, di- and tricistronic RNAs. The maturation of the polycistronic transcripts is likely to involve endonucleolytic cleavage where tRNAs serve as processing signals. Reverse transcription polymerase chain reactions across the intervening regions between the six major polycistronic transcripts suggest that these transcripts were once part of an even larger transcript. Our findings indicate that the mitochondrial genome of A. castellanii is transcribed from only one or two promoters, very similar to the mode of transcription in the mitochondria of its close relative Dictyostelium discoideum, where transcription is known to occur from only a single transcription initiation site. Transcription initiation from a minimal number of promoters despite a large genome size may be an emerging trend in the mitochondria of protists.

  2. Swedish isolates of Vibrio cholerae enhance their survival when interacted intracellularly with Acanthamoeba castellanii.

    PubMed

    Shanan, Salah; Bayoumi, Magdi; Saeed, Amir; Sandström, Gunnar; Abd, Hadi

    2016-01-01

    Vibrio cholerae is a Gram-negative bacterium that occurs naturally in aquatic environment. Only V. cholerae O1 and V. cholerae O139 produce cholera toxin and cause cholera, other serogroups can cause gastroenteritis, open wounds infection, and septicaemia. V. cholerae O1 and V. cholerae O139 grow and survive inside Acanthamoeba castellanii. The aim of this study is to investigate the interactions of the Swedish clinical isolates V. cholerae O3, V. cholerae O4, V. cholerae O5, V. cholerae O11, and V. cholerae O160 with A. castellanii. The interaction between A. castellanii and V. cholerae strains was studied by means of amoeba cell counts, viable counts of the bacteria in the absence or presence of amoebae, and of the intracellularly growing bacteria, visualised by electron microscopy. These results show that all V. cholerae can grow and survive outside and inside the amoebae, disclosing that V. cholerae O3, V. cholerae O4, V. cholerae O5, V. cholerae O11, and V. cholerae O160 all can be considered as facultative intracellular bacteria. PMID:27118300

  3. Relationship between Legionella pneumophila and Acanthamoeba polyphaga: Physiological status and susceptibility to chemical inactivation

    SciTech Connect

    Barker, J.; Farrell, I. ); Brown, M.R.W.; Collier, P.J.; Gilbert, P. )

    1992-08-01

    Survival studies were conducted on Legionella pneumophila cells that had been grown intracellulary in Acanthamoeba polyphaga and then exposed to polyhexamethylene biguanide (PHMB), benzisothiazolone (BIT), and 5-chloro-N-methylisothiazolone (CMIT). Susceptibilities were also determined for L. pneumophila grown under iron-sufficient and iron-depleted conditions. BIT was relatively ineffective against cells to PHMB and CMIT. The activities of all three biocides were greatly reduced against L. pneumophila grown in amoebae. PHMB (1 [times] MIC) gave 99.99% reductions in viability for cultures grown in broth within 6 h and no detectable survivors at 24 h but only 90 and 99.9% killing at 6 h and 24 h, respectively, for cells grown in amoebae. The antimicrobial properties of the three biocides against A. polyphaga were also determined. The majority of amoebae recovered from BIT treatment, but few, if any, survived CMIT treatment or exposure of PHMB. This study not only shows the profound effect that intra-amoebal growth has on the physiological status and antimicrobial susceptibility of L. pneumophila but also reveals PHMB to be a potential biocide for effective water treatment. In this respect, PHMB has significant activity, below its recommended use concentrations, against both the host amoeba and L. pneumophila.

  4. Relationship between Legionella pneumophila and Acanthamoeba polyphaga: physiological status and susceptibility to chemical inactivation.

    PubMed Central

    Barker, J; Brown, M R; Collier, P J; Farrell, I; Gilbert, P

    1992-01-01

    Survival studies were conducted on Legionella pneumophila cells that had been grown intracellularly in Acanthamoeba polyphaga and then exposed to polyhexamethylene biguanide (PHMB), benzisothiazolone (BIT), and 5-chloro-N-methylisothiazolone (CMIT). Susceptibilities were also determined for L. pneumophila grown under iron-sufficient and iron-depleted conditions. BIT was relatively ineffective against cells grown under iron depletion; in contrast, iron-depleted conditions increased the susceptibilities of cells to PHMB and CMIT. The activities of all three biocides were greatly reduced against L. pneumophila grown in amoebae. PHMB (1 x MIC) gave 99.99% reductions in viability for cultures grown in broth within 6 h and no detectable survivors at 24 h but only 90 and 99.9% killing at 6 h and 24 h, respectively, for cells grown in amoebae. The antimicrobial properties of the three biocides against A. polyphaga were also determined. The majority of amoebae recovered from BIT treatment, but few, if any, survived CMIT treatment or exposure to PHMB. This study not only shows the profound effect that intra-amoebal growth has on the physiological status and antimicrobial susceptibility of L. pneumophila but also reveals PHMB to be a potential biocide for effective water treatment. In this respect, PHMB has significant activity, below its recommended use concentrations, against both the host amoeba and L. pneumophila. PMID:1514790

  5. Molecular and biochemical characterization of a novel actin bundling protein in Acanthamoeba

    PubMed Central

    Alafag, Joanna It-itan; Moon, Eun-Kyung; Hong, Yeon-Chul; Chung, Dong-Il

    2006-01-01

    Actin binding proteins play key roles in cell structure and movement particularly as regulators of the assembly, stability and localization of actin filaments in the cytoplasm. In the present study, a cDNA clone encoding an actin bundling protein named as AhABP was isolated from Acanthamoeba healyi, a causative agent of granulomatous amebic encephalitis. This clone exhibited high similarity with genes of Physarum polycephalum and Dictyostelium discoideum, which encode actin bundling proteins. Domain search analysis revealed the presence of essential conserved regions, i.e., an active actin binding site and 2 putative calcium binding EF-hands. Transfected amoeba cells demonstrated that AhABP is primarily localized in phagocytic cups, peripheral edges, pseudopods, and in cortical cytoplasm where actins are most abundant. Moreover, AhABP after the deletion of essential regions formed ellipsoidal inclusions within transfected cells. High-speed co-sedimentation assays revealed that AhABP directly interacted with actin in the presence of up to 10 µM of calcium. Under the electron microscope, thick parallel bundles were formed by full length AhABP, in contrast to the thin actin bundles formed by constructs with deletion sites. In the light of these results, we conclude that AhABP is a novel actin bundling protein that is importantly associated with actin filaments in the cytoplasm. PMID:17170575

  6. Yersinia pseudotuberculosis IP32953 survives and replicates in trophozoites and persists in cysts of Acanthamoeba castellanii.

    PubMed

    Santos-Montañez, Jennifer; Benavides-Montaño, Javier A; Hinz, Angela K; Vadyvaloo, Viveka

    2015-07-01

    Yersinia pseudotuberculosis is a foodborne enteric pathogen that causes a mild self-limiting diarrhea in humans. Yersinia pseudotuberculosis is able to persist in soil and water and in association with fresh produce, but the mechanism by which it persists is unknown. It has been shown that Y. pseudotuberculosis co-occurs with protozoans in these environments; therefore, this study investigates if bacterivorous free-living amoeba (FLA) are able to support persistence of Y. pseudotuberculosis. Coculture studies of Y. pseudotuberculosis and the prototype FLA, Acanthamoeba castellanii revealed that bacteria had an enhanced capacity to survive in association with amoeba and in the absence of any cytotoxic effects. Yersinia pseudotuberculosis is able to survive and replicate in trophozoites specifically localized within vacuoles, and persists within cysts over a period of at least a week. These data present the first evidence that Y. pseudotuberculosis is able to resist the bacterivorous nature of FLA and instead exhibits an enhanced ability to replicate and persist in coculture with amoeba. This study sheds light on the potential role of FLA in the ecology of Y. pseudotuberculosis which may have implications for food safety. PMID:26025069

  7. Mass spectrometry characterization of trypanothione and novel peptides of medical importance isolated from Acanthamoeba polyphaga.

    PubMed

    Ondarza, Raul N; Hernandez, Eva; Hurtado, Gerardo; Woolery, Mathew; Hernandez-Sandoval, Francisco

    2013-04-01

    This paper presents unequivocal results about the presence of trypanothione and its precursor glutathionespermidine from the opportunistic human pathogen Acanthamoeba polyphaga. They were isolated by RP-HPLC as thiolbimane derivatives and characterized using matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF/TOF). Additionally RP-HPLC demonstrated that thiol-bimane compounds corresponding to cysteine and glutathione were also present in A. polyphaga. Besides trypanothione, we want to report four new peptides in trophozoites, a tetrapeptide, a hexapeptide, a heptapeptide and a nonapeptide. Trypanothione and two of the thiol peptides, the hexapeptide and heptapeptide, are oxidized since the reduced forms increase in amount when the normal extract is treated by DTT or by electrolytic reduction that convert the oxidized forms to reduced ones. On the other hand, they disappear when the amoeba extract is treated with NEM or when the amoeba culture is treated with various inhibitors of NADPH-dependent disulfidereducing enzymes. Comparison of the thiol peptides, including trypanothione from A. polyphaga with extracts from human lymphocytes showed that they are not present in the latter. Therefore, some of the peptides here reported could be used as antigens for rapid detection of these parasites. In regard to the presence of the enzymes that synthesize and reduce trypanothione in A. polyphaga we suggest that they can be used as drug targets. PMID:23808873

  8. Interaction of Aspergillus fumigatus conidia with Acanthamoeba castellanii parallels macrophage-fungus interactions.

    PubMed

    Van Waeyenberghe, Lieven; Baré, Julie; Pasmans, Frank; Claeys, Myriam; Bert, Wim; Haesebrouck, Freddy; Houf, Kurt; Martel, An

    2013-12-01

    Aspergillus fumigatus and free-living amoebae are common inhabitants of soil. Mechanisms of A. fumigatus to circumvent the amoeba's digestion may facilitate overcoming the vertebrate macrophage defence mechanisms. We performed co-culture experiments using A. fumigatus conidia and the amoeba Acanthamoeba castellanii. Approximately 25% of the amoebae ingested A. fumigatus conidia after 1 h of contact. During intra-amoebal passage, part of the ingested conidia was able to escape the food vacuole and to germinate inside the cytoplasm of A. castellanii. Fungal release into the extra-protozoan environment by exocytosis of conidia or by germination was observed with light and transmission electron microscopy. These processes resulted in structural changes in A. castellanii, leading to amoebal permeabilization without cell lysis. In conclusion, A. castellanii internalizes A. fumigatus conidia, resulting in fungal intracellular germination and subsequent amoebal death. As such, this interaction highly resembles that of A. fumigatus with mammalian and avian macrophages. This suggests that A. fumigatus virulence mechanisms to evade macrophage killing may be acquired by co-evolutionary interactions among A. fumigatus and environmental amoebae. PMID:24249290

  9. Axenic mass cultivation of the free-living soil amoeba, Acanthamoeba castellanii in a laboratory fermentor.

    PubMed

    Weekers, P H; Wijen, J P; Lomans, B P; Vogels, G D

    1996-05-01

    Axenic mass cultivation of Acanthamoeba castellanii in laboratory fermentors (141) yielded after 20 days approximately 3 g cells (wet weight). After a short lag phase amoebal cell numbers increased exponentially to a maximum of 3.5 x 10(5) cells per ml until cell death occurred after 20 days. Optical density and protein concentrations revealed identical patterns. During amoebal growth only 12-19% of the initially added glucose (100 mM) as sole carbon source was used. Large amounts of ammonia (1 g in 10.51 culture volume) were excreted into the medium which subsequently raised the pH from 6.6 to 7.7, and from 6.6 to 6.8 in 2 and 20 mM buffered media, respectively. Growth inhibition and cell death could not be explained by a depletion of glucose or oxygen limitations during growth. The production of ammonia had a growth inhibitory effect, however, the sudden termination of the exponential growth phase and cell death could not be explained by the toxic influence of ammonia only. PMID:8836429

  10. Interaction of Acinetobacter baumannii 19606 and 1656-2 with Acanthamoeba castellanii.

    PubMed

    Tamang, Migma Dorji; Kim, Shukho; Kim, Sung-Min; Kong, Hyun-Hee; Kim, Jungmin

    2011-10-01

    Acinetobacter baumannii is virtually avirulent for healthy people but maintains a high virulence among critically ill patients or immuno-compromised individuals. The ability of A. baumannii to adhere to cells and persist on surfaces as biofilms could be central to its pathogenicity. In the present study, we compared the virulence of the A. baumannii 1656-2 clinical strain, which is able to form a thick biofilm, with the virulence of the A. baumannii type strain (ATCC 19606(T)). Acanthamoeba castellanii, a single-celled organism, was used as the host model system to study the virulence of A. baumannii. Compared to A. baumannii ATCC 19606(T), A. baumannii 1656-2 exhibited a higher ability to adhere and invade A. castellanii cells and had a higher killing rate of A. castellanii cells. Furthermore, co-incubation of the amoeba cells and the cell-free supernatant of A. baumannii resulted in the cell death of the amoebae. Heat inactivation or proteinase K treatment of the supernatant did not eliminate its cytotoxicity, suggesting heat stable non-protein factors are responsible for its cytotoxicity to A. castellanii cells. In conclusion, this study for the first time has revealed the capacity of the A. baumannii strain and/or its metabolic products to induce cytotoxicity in A. castellanii cells. PMID:22068504

  11. Swedish isolates of Vibrio cholerae enhance their survival when interacted intracellularly with Acanthamoeba castellanii

    PubMed Central

    Shanan, Salah; Bayoumi, Magdi; Saeed, Amir; Sandström, Gunnar; Abd, Hadi

    2016-01-01

    Vibrio cholerae is a Gram-negative bacterium that occurs naturally in aquatic environment. Only V. cholerae O1 and V. cholerae O139 produce cholera toxin and cause cholera, other serogroups can cause gastroenteritis, open wounds infection, and septicaemia. V. cholerae O1 and V. cholerae O139 grow and survive inside Acanthamoeba castellanii. The aim of this study is to investigate the interactions of the Swedish clinical isolates V. cholerae O3, V. cholerae O4, V. cholerae O5, V. cholerae O11, and V. cholerae O160 with A. castellanii. The interaction between A. castellanii and V. cholerae strains was studied by means of amoeba cell counts, viable counts of the bacteria in the absence or presence of amoebae, and of the intracellularly growing bacteria, visualised by electron microscopy. These results show that all V. cholerae can grow and survive outside and inside the amoebae, disclosing that V. cholerae O3, V. cholerae O4, V. cholerae O5, V. cholerae O11, and V. cholerae O160 all can be considered as facultative intracellular bacteria. PMID:27118300

  12. Apoptosis-like cell death induced by Salmonella in Acanthamoeba rhysodes.

    PubMed

    Feng, Ye; Hsiao, Yi-Hsing; Chen, Hsiu-Ling; Chu, Chishih; Tang, Petrus; Chiu, Cheng-Hsun

    2009-08-01

    Free-living amoebae act as environmental hosts of several intracellular pathogens. We examined the interaction between Acanthamoeba rhysodes and Salmonella, a human intracellular pathogen. There was no difference among three different serovars of Salmonella in terms of their growth within A. rhysodes over time. The number of intracellular bacteria increased at 6 h post-infection, and the viability of A. rhysodes was significantly reduced at 24 h post-infection. Amoebic cell death was characterized by TUNEL and Annexin V assay, without DNA ladder identified, indicating an apoptosis-like cell death in Salmonella-infected A. rhysodes. Global gene expression screening between intracellular and extracellular Salmonella by microarray and quantitative PCR showed that genes from Salmonella pathogenicity islands and virulence plasmid were up-regulated within A. rhysodes. The phase-dependent expression pattern suggests their distinct roles in the pathogenesis. A. rhysodes and Salmonella provide a model to study transient symbiosis between bacterial pathogens and protozoa in an aquatic ecosystem. PMID:19446019

  13. Yersinia pseudotuberculosis IP32953 survives and replicates in trophozoites and persists in cysts of Acanthamoeba castellanii

    PubMed Central

    Santos-Montañez, Jennifer; Benavides-Montaño, Javier A.; Hinz, Angela K.; Vadyvaloo, Viveka

    2015-01-01

    Yersinia pseudotuberculosis is a foodborne enteric pathogen that causes a mild self-limiting diarrhea in humans. Yersinia pseudotuberculosis is able to persist in soil and water and in association with fresh produce, but the mechanism by which it persists is unknown. It has been shown that Y. pseudotuberculosis co-occurs with protozoans in these environments; therefore, this study investigates if bacterivorous free-living amoeba (FLA) are able to support persistence of Y. pseudotuberculosis. Coculture studies of Y. pseudotuberculosis and the prototype FLA, Acanthamoeba castellanii revealed that bacteria had an enhanced capacity to survive in association with amoeba and in the absence of any cytotoxic effects. Yersinia pseudotuberculosis is able to survive and replicate in trophozoites specifically localized within vacuoles, and persists within cysts over a period of at least a week. These data present the first evidence that Y. pseudotuberculosis is able to resist the bacterivorous nature of FLA and instead exhibits an enhanced ability to replicate and persist in coculture with amoeba. This study sheds light on the potential role of FLA in the ecology of Y. pseudotuberculosis which may have implications for food safety. PMID:26025069

  14. Increased Persistence of Salmonella enterica Serovar Typhi in the Presence of Acanthamoeba castellanii▿

    PubMed Central

    Douesnard-Malo, Frédéric; Daigle, France

    2011-01-01

    Salmonella enterica serovar Typhi (S. Typhi) is the etiological agent of the systemic disease typhoid fever. Transmission occurs via ingestion of contaminated food or water. S. Typhi is specific to humans, and no animal or environmental reservoirs are known. As the free-living amoeba Acanthamoeba castellanii is an environmental host for many pathogenic bacteria, this study investigates interactions between S. Typhi and A. castellanii by using cocultures. Growth of both organisms was estimated by cell count, viable count, flow cytometry, and fluorescence microscopy. Results indicate that S. Typhi can survive at least 3 weeks when grown with A. castellanii, as opposed to less than 10 days when grown as singly cultured bacteria under the same conditions. Interestingly, growth rates of amoebae after 14 days were similar in cocultures or when amoebae were singly cultured, suggesting that S. Typhi is not cytotoxic to A. castellanii. Bacteria surviving in coculture were not intracellular and did not require a physical contact with amoebae for their survival. These results suggest that S. Typhi may have a selective advantage when it is associated with A. castellanii and that amoebae may contribute to S. Typhi persistence in the environment. PMID:21926221

  15. Discovery and characterization of Acanthamoeba castellanii mitochondrial 5S rRNA.

    PubMed

    Bullerwell, Charles E; Schnare, Murray N; Gray, Michael W

    2003-03-01

    Although 5S rRNA is a highly conserved and universal component of eubacterial, archaeal, chloroplast, and eukaryotic cytoplasmic ribosomes, a mitochondrial DNA-encoded 5S rRNA has so far been identified only in land plants and certain protists. This raises the question of whether 5S rRNA is actually required for and used in mitochondrial translation. In the protist Acanthamoeba castellanii, BLAST searches fail to reveal a 5S rRNA gene in the complete mitochondrial genome sequence, nor is a 5S-sized RNA species detectable in ethidium bromide-stained gels of highly purified mitochondrial RNA preparations. Here we show that an alternative visualization technique, UV shadowing, readily detects a novel, mitochondrion-specific small RNA in A. castellanii mitochondrial RNA preparations, and that this RNA species is, in fact, a 5S rRNA encoded by the A. castellanii mitochondrial genome. These results emphasize the need for caution when interpreting negative results that suggest the absence of 5S rRNA and/or a mitochondrial DNA-encoded 5S rRNA sequence in other (particularly protist) mitochondrial systems.

  16. Composition of the mitochondrial electron transport chain in acanthamoeba castellanii: structural and evolutionary insights.

    PubMed

    Gawryluk, Ryan M R; Chisholm, Kenneth A; Pinto, Devanand M; Gray, Michael W

    2012-11-01

    The mitochondrion, derived in evolution from an α-proteobacterial progenitor, plays a key metabolic role in eukaryotes. Mitochondria house the electron transport chain (ETC) that couples oxidation of organic substrates and electron transfer to proton pumping and synthesis of ATP. The ETC comprises several multiprotein enzyme complexes, all of which have counterparts in bacteria. However, mitochondrial ETC assemblies from animals, plants and fungi are generally more complex than their bacterial counterparts, with a number of 'supernumerary' subunits appearing early in eukaryotic evolution. Little is known, however, about the ETC of unicellular eukaryotes (protists), which are key to understanding the evolution of mitochondria and the ETC. We present an analysis of the ETC proteome from Acanthamoeba castellanii, an ecologically, medically and evolutionarily important member of Amoebozoa (sister to Opisthokonta). Data obtained from tandem mass spectrometric (MS/MS) analyses of purified mitochondria as well as ETC complexes isolated via blue native polyacrylamide gel electrophoresis are combined with the results of bioinformatic queries of sequence databases. Our bioinformatic analyses have identified most of the ETC subunits found in other eukaryotes, confirming and extending previous observations. The assignment of proteins as ETC subunits by MS/MS provides important insights into the primary structures of ETC proteins and makes possible, through the use of sensitive profile-based similarity searches, the identification of novel constituents of the ETC along with the annotation of highly divergent but phylogenetically conserved ETC subunits.

  17. Acanthamoeba and other free-living amoebae in bat guano, an extreme habitat.

    PubMed

    Mulec, Janez; Dietersdorfer, Elisabeth; Üstüntürk-Onan, Miray; Walochnik, Julia

    2016-04-01

    Several representatives of the so-called free-living amoebae (FLA) are of medical relevance, not only as facultative pathogens but also as vehicles for pathogenic bacteria. Some FLA can survive and even grow under extreme environmental conditions. Bat guano is an exceptional habitat, the conditions becoming gradually more extreme with aging. In the current study, samples of bat guano of different ages from five caves in Slovenia were screened for the presence of FLA. FLA were isolated from almost all guano samples, including guano with a pH of 3.5. Only the two samples that had been drawn from >20-year-old guano were negative for FLA. Generally, FLA diversity correlated to high concentrations of cultivable bacteria (∼10(8) CFU/g) and fungi (∼10(5) CFU/g). Interestingly, the absence of FLA in seasoned guanos was mirrored by the presence of dictyostelid slime moulds. The isolated amoebae were identified as belonging to the genera Acanthamoeba, Copromyxa, Naegleria, Sappinia, Tetramitus, Thecamoeba, Vahlkampfia, Vannella and Vermamoeba. To the best of our knowledge, this is the first study on the diversity of FLA in guano. PMID:26678653

  18. Inhibition of Acanthamoeba myosin I heavy chain kinase by Ca(2+)-calmodulin.

    PubMed

    Brzeska, H; Kulesza-Lipka, D; Korn, E D

    1992-11-25

    The actin-activated Mg(2+)-ATPase activity of Acanthamoeba myosins I depends on phosphorylation of their single heavy chains by myosin I heavy chain kinase. Kinase activity is enhanced > 50-fold by autophosphorylation at multiple sites. The rate of kinase autophosphorylation is increased approximately 20-fold by acidic phospholipids independent of the presence of Ca2+ and diglycerides. We show in this paper that Ca(2+)-calmodulin inhibits phospholipid-stimulated autophosphorylation of myosin I heavy chain kinase and hence also inhibits the catalytic activity of unphosphorylated kinase in the presence of phospholipid. Ca(2+)-calmodulin does not inhibit kinase activity in the absence of phospholipid. Micromolar Ca(2+)-calmodulin also inhibits binding of myosin I heavy chain kinase to phospholipid vesicles and purified plasma membranes. Proteolytic removal of a 7-kDa NH2-terminal segment from the 97-kDa kinase prevents binding of both calmodulin and phospholipid; therefore, we propose that they bind to the same or overlapping sites. These data provide a mechanism by which Ca2+ could inhibit the actin-activated Mg(2+)-ATPase activity of the myosin I isozymes in vivo and thus regulate myosin I-dependent motile activities. PMID:1331103

  19. Apoptosis-like cell death induced by Salmonella in Acanthamoeba rhysodes.

    PubMed

    Feng, Ye; Hsiao, Yi-Hsing; Chen, Hsiu-Ling; Chu, Chishih; Tang, Petrus; Chiu, Cheng-Hsun

    2009-08-01

    Free-living amoebae act as environmental hosts of several intracellular pathogens. We examined the interaction between Acanthamoeba rhysodes and Salmonella, a human intracellular pathogen. There was no difference among three different serovars of Salmonella in terms of their growth within A. rhysodes over time. The number of intracellular bacteria increased at 6 h post-infection, and the viability of A. rhysodes was significantly reduced at 24 h post-infection. Amoebic cell death was characterized by TUNEL and Annexin V assay, without DNA ladder identified, indicating an apoptosis-like cell death in Salmonella-infected A. rhysodes. Global gene expression screening between intracellular and extracellular Salmonella by microarray and quantitative PCR showed that genes from Salmonella pathogenicity islands and virulence plasmid were up-regulated within A. rhysodes. The phase-dependent expression pattern suggests their distinct roles in the pathogenesis. A. rhysodes and Salmonella provide a model to study transient symbiosis between bacterial pathogens and protozoa in an aquatic ecosystem.

  20. Ultrastructural Characterization of the Giant Volcano-like Virus Factory of Acanthamoeba polyphaga Mimivirus

    PubMed Central

    Suzan-Monti, Marie; Scola, Bernard La; Barrassi, Lina; Espinosa, Leon; Raoult, Didier

    2007-01-01

    Acanthamoeba polyphaga Mimivirus is a giant double-stranded DNA virus defining a new genus, the Mimiviridae, among the Nucleo-Cytoplasmic Large DNA Viruses (NCLDV). We used utrastructural studies to shed light on the different steps of the Mimivirus replication cycle: entry via phagocytosis, release of viral DNA into the cell cytoplasm through fusion of viral and vacuolar membranes, and finally viral morphogenesis in an extraordinary giant cytoplasmic virus factory (VF). Fluorescent staining of the AT-rich Mimivirus DNA showed that it enters the host nucleus prior to the generation of a cytoplasmic independent replication centre that forms the core of the VF. Assembly and filling of viral capsids were observed within the replication centre, before release into the cell cytoplasm where progeny virions accumulated. 3D reconstruction from fluorescent and differential contrast interference images revealed the VF emerging from the cell surface as a volcano-like structure. Its size dramatically grew during the 24 h infectious lytic cycle. Our results showed that Mimivirus replication is an extremely efficient process that results from a rapid takeover of cellular machinery, and takes place in a unique and autonomous giant assembly centre, leading to the release of a large number of complex virions through amoebal lysis. PMID:17389919

  1. Use of Subgenic 18S Ribosomal DNA PCR and Sequencing for Genus and Genotype Identification of Acanthamoebae from Humans with Keratitis and from Sewage Sludge

    PubMed Central

    Schroeder, Jill M.; Booton, Gregory C.; Hay, John; Niszl, Ingrid A.; Seal, David V.; Markus, Miles B.; Fuerst, Paul A.; Byers, Thomas J.

    2001-01-01

    This study identified subgenic PCR amplimers from 18S rDNA that were (i) highly specific for the genus Acanthamoeba, (ii) obtainable from all known genotypes, and (iii) useful for identification of individual genotypes. A 423- to 551-bp Acanthamoeba-specific amplimer ASA.S1 obtained with primers JDP1 and JDP2 was the most reliable for purposes i and ii. A variable region within this amplimer also identified genotype clusters, but purpose iii was best achieved with sequencing of the genotype-specific amplimer GTSA.B1. Because this amplimer could be obtained from any eukaryote, axenic Acanthamoeba cultures were required for its study. GTSA.B1, produced with primers CRN5 and 1137, extended between reference bp 1 and 1475. Genotypic identification relied on three segments: bp 178 to 355, 705 to 926, and 1175 to 1379. ASA.S1 was obtained from single amoeba, from cultures of all known 18S rDNA genotypes, and from corneal scrapings of Scottish patients with suspected Acanthamoeba keratitis (AK). The AK PCR findings were consistent with culture results for 11 of 15 culture-positive specimens and detected Acanthamoeba in one of nine culture-negative specimens. ASA.S1 sequences were examined for 6 of the 11 culture-positive isolates and were most closely associated with genotypic cluster T3-T4-T11. A similar distance analysis using GTSA.B1 sequences identified nine South African AK-associated isolates as genotype T4 and three isolates from sewage sludge as genotype T5. Our results demonstrate the usefulness of 18S ribosomal DNA PCR amplimers ASA.S1 and GTSA.B1 for Acanthamoeba-specific detection and reliable genotyping, respectively, and provide further evidence that T4 is the predominant genotype in AK. PMID:11326011

  2. Contact lens care solution killing efficacy against Acanthamoeba castellanii by in vitro testing and live-imaging.

    PubMed

    Kolar, Satya Sree N; Manarang, Joseph C; Burns, Alan R; Miller, William L; McDermott, Alison M; Bergmanson, Jan P G

    2015-12-01

    In the past decade there has been an increased incidence of Acanthamoeba keratitis, particularly in contact lens wearers. The aim of this study was to utilize in vitro killing assays and to establish a novel, time-lapse, live-cell imaging methodology to demonstrate the efficacy of contact lens care solutions in eradicating Acanthamoeba castellanii (A. castellanii) trophozoites and cysts. Standard qualitative and quantitative in vitro assays were performed along with novel time-lapse imaging coupled with fluorescent dye staining that signals cell death. Quantitative data obtained demonstrated that 3% non-ophthalmic hydrogen peroxide demonstrated the highest percent killing at 87.4% corresponding to a 4.4 log kill. The other contact lens care solutions which showed a 72.9 to 29.2% killing which was consistent with 4.3-2.8 log reduction in trophozoite viability. Both analytical approaches revealed that polyquaternium/PHMB-based was the least efficacious in terms of trophicidal activity. The cysticidal activity of the solutions was much less than activity against trophozoites and frequently was not detected. Live-imaging provided a novel visual endpoint for characterizing the trophocidal activity of the care solutions. All solutions caused rapid rounding or pseudocyst formation of the trophozoites, reduced motility and the appearance of different morphotypes. Polyquaternium/alexidine-based and peroxide-based lens care system induced the most visible damage indicated by significant accumulation of debris from ruptured cells. Polyquaternium/PHMB-based was the least effective showing rounding of the cells but minimal death. These observations are in keeping with care solution biocides having prominent activity at the plasma membrane of Acanthamoeba.

  3. Contact lens care solution killing efficacy against Acanthamoeba castellanii by in vitro testing and live-imaging.

    PubMed

    Kolar, Satya Sree N; Manarang, Joseph C; Burns, Alan R; Miller, William L; McDermott, Alison M; Bergmanson, Jan P G

    2015-12-01

    In the past decade there has been an increased incidence of Acanthamoeba keratitis, particularly in contact lens wearers. The aim of this study was to utilize in vitro killing assays and to establish a novel, time-lapse, live-cell imaging methodology to demonstrate the efficacy of contact lens care solutions in eradicating Acanthamoeba castellanii (A. castellanii) trophozoites and cysts. Standard qualitative and quantitative in vitro assays were performed along with novel time-lapse imaging coupled with fluorescent dye staining that signals cell death. Quantitative data obtained demonstrated that 3% non-ophthalmic hydrogen peroxide demonstrated the highest percent killing at 87.4% corresponding to a 4.4 log kill. The other contact lens care solutions which showed a 72.9 to 29.2% killing which was consistent with 4.3-2.8 log reduction in trophozoite viability. Both analytical approaches revealed that polyquaternium/PHMB-based was the least efficacious in terms of trophicidal activity. The cysticidal activity of the solutions was much less than activity against trophozoites and frequently was not detected. Live-imaging provided a novel visual endpoint for characterizing the trophocidal activity of the care solutions. All solutions caused rapid rounding or pseudocyst formation of the trophozoites, reduced motility and the appearance of different morphotypes. Polyquaternium/alexidine-based and peroxide-based lens care system induced the most visible damage indicated by significant accumulation of debris from ruptured cells. Polyquaternium/PHMB-based was the least effective showing rounding of the cells but minimal death. These observations are in keeping with care solution biocides having prominent activity at the plasma membrane of Acanthamoeba. PMID:26208952

  4. Free-living Acanthamoeba and Naegleria spp. amebae in water sources of León, Nicaragua.

    PubMed

    Leiva, Byron; Clasdotter, Emma; Linder, Ewert; Winiecka-Krusnell, Jadwiga

    2008-06-01

    Free-living amebae (FLA) are known to occur worldwide in water-related biotopes, but only limited information is available on these organisms in developing countries and so far no information on their presence is available from Nicaragua. The aims of this study were to evaluate the prevalence of potentially pathogenic Acanthamoeba spp. and Naegleria spp. in different water sources to which the population of Le6n municipality is exposed. Since pathogenic amebae are thermotolerant, we were especially interested in the occurrence of FLA in geothermal areas. Water samples were collected from Le6n area in Nicaragua: 88 samples were from rivers and springs, 111 from wells, 74 from water taps and 21 from water tanks in urban and suburban Le6n and from three nearby geothermal areas of San Jacinto, Posoltega and Tipitapa. Amebae were identified using morphological and physiological criteria, immunohistochemical staining procedures and molecular methods. Indirect immunofluorescent test was performed on cysts and trophozoites fixed on microscopical slides and incubated for 30 min at room temperature in separate experiments with the following antibodies: rabbit-anti N fowleri/N lovanensis (Nf-Pab), mouse monoclonal antibody anti N. fowleri (Nf-5D12u), rabbit antibodies against Acanthamoeba spp. And fluorescent in situ hybridization (FISH) was performed using 18S rRNA-targeted fluorescent oligonucleotide probes. Probes: GSP for the detection of Acanthamoeba and NAEG1088 for the detection of Naegleria. Free-living amebae were recovered from approximately 43 % of the samples. Acanthamoeba spp was found in 21% of samples from León municipality and in 2% of samples from geothermal areas. Amoeboflagellates were found in 10 % of samples from Le6n and in 19% in geothermal areas. Fifty three percent of tested wells in the geothermal area contained thermotolerant amoeboflagellates. Naegleria spp. was identified in 24 out of 39 (61.5 %) of isolated amoeboflagellates. Twelve of them were

  5. Quantification and Characterization of Phagocytosis in the Soil Amoeba Acanthamoeba castellanii by Flow Cytometry

    PubMed Central

    Avery, S. V.; Harwood, J. L.; Lloyd, D.

    1995-01-01

    Phagocytosis in the common grazing soil amoeba Acanthamoeba castellanii was characterized by flow cytometry. Uptake of fluorescently labelled latex microbeads by cells was quantified by appropriate setting of thresholds on light scatter channels and, subsequently, on fluorescence histograms. Confocal laser scanning microscopy was used to verify the effectiveness of sodium azide as a control for distinguishing between cell surface binding and internalization of beads. It was found that binding of beads at the cell surface was complete within 5 min and 80% of cells had beads associated with them after 10 min. However, the total number of phagocytosed beads continued to rise up to 2 h. The prolonged increase in numbers of beads phagocytosed was due to cell populations containing increasing numbers of beads peaking at increasing time intervals from the onset of phagocytosis. Fine adjustment of thresholds on light scatter channels was used to fractionate cells according to cell volume (cell cycle stage). Phagocytotic activity was approximately threefold higher in the largest (oldest) than in the smallest (newly divided) cells of A. castellanii and showed some evidence of periodicity. At no stage in the cell cycle did phagocytosis cease. Binding and phagocytosis of beads were also markedly influenced by culture age and rate of rotary agitation of cell suspensions. Saturation of phagocytosis (per cell) at increasing bead or decreasing cell concentrations occurred at bead/cell ratios exceeding 10:1. This was probably a result of a limitation of the vacuolar uptake system of A. castellanii, as no saturation of bead binding was evident. The advantages of flow cytometry for characterization of phagocytosis at the single-cell level in heterogeneous protozoal populations and the significance of the present results are discussed. PMID:16534962

  6. The efficacy of simulated solar disinfection (SODIS) against Ascaris, Giardia, Acanthamoeba, Naegleria, Entamoeba and Cryptosporidium.

    PubMed

    Heaselgrave, Wayne; Kilvington, Simon

    2011-08-01

    The antimicrobial activity of simulated solar disinfection (SODIS) in the presence and absence of riboflavin against various protozoa and helminth organisms was investigated in this study. Assays were conducted in transparent 12 well microtitre plates containing a suspension of test organisms in the presence or absence of 250 μM riboflavin. Plates were exposed to simulated sunlight at an optical irradiance of 550 Wm(-2) (watts per square metre) delivered from a SUNTEST™ CPS+ solar simulator. Aliquots of the test suspensions were taken at set time points and the viability of the test organisms was determined by either culture, microscopy or flow cytometry where applicable. With Acanthamoeba, Naegleria, Entamoeba and Giardia exposure to SODIS at an optical irradiance of 550 Wm(-2) for up to 6h resulted in significant inactivation of these organisms. The addition of riboflavin to this system significantly increased the level of inactivation observed with cysts of A. castellanii. With Cryptosporidium oocysts and Ascaris ova exposure to SODIS in the presence and absence of riboflavin for 6-8h resulted in a negligible reduction in viability of both organisms. In this present study we have been able to show that SODIS is effective against a variety of previously untested waterborne organisms and with A. castellanii cysts the addition of micro-molar concentrations of riboflavin can enhance cyst inactivation. However, care must be taken as Ascaris larvae continue to develop inside the ova after exposure to SODIS and Cryptosporidium remain impermeable to propidium iodide staining indicating they may still be infectious.

  7. Genome Segregation and Packaging Machinery in Acanthamoeba polyphaga Mimivirus Is Reminiscent of Bacterial Apparatus

    PubMed Central

    Chelikani, Venkata; Ranjan, Tushar; Zade, Amrutraj; Shukla, Avi

    2014-01-01

    ABSTRACT Genome packaging is a critical step in the virion assembly process. The putative ATP-driven genome packaging motor of Acanthamoeba polyphaga mimivirus (APMV) and other nucleocytoplasmic large DNA viruses (NCLDVs) is a distant ortholog of prokaryotic chromosome segregation motors, such as FtsK and HerA, rather than other viral packaging motors, such as large terminase. Intriguingly, APMV also encodes other components, i.e., three putative serine recombinases and a putative type II topoisomerase, all of which are essential for chromosome segregation in prokaryotes. Based on our analyses of these components and taking the limited available literature into account, here we propose for the first time a model for genome segregation and packaging in APMV that can possibly be extended to NCLDV subfamilies, except perhaps Poxviridae and Ascoviridae. This model might represent a unique variation of the prokaryotic system acquired and contrived by the large DNA viruses of eukaryotes. It is also consistent with previous observations that unicellular eukaryotes, such as amoebae, are melting pots for the advent of chimeric organisms with novel mechanisms. IMPORTANCE Extremely large viruses with DNA genomes infect a wide range of eukaryotes, from human beings to amoebae and from crocodiles to algae. These large DNA viruses, unlike their much smaller cousins, have the capability of making most of the protein components required for their multiplication. Once they infect the cell, these viruses set up viral replication centers, known as viral factories, to carry out their multiplication with very little help from the host. Our sequence analyses show that there is remarkable similarity between prokaryotes (bacteria and archaea) and large DNA viruses, such as mimivirus, vaccinia virus, and pandoravirus, in the way that they process their newly synthesized genetic material to make sure that only one copy of the complete genome is generated and is meticulously placed inside

  8. Draft Genome Sequence of High-Temperature-Adapted Protochlamydia sp. HS-T3, an Amoebal Endosymbiotic Bacterium Found in Acanthamoeba Isolated from a Hot Spring in Japan.

    PubMed

    Yamaguchi, Hiroyuki; Matsuo, Junji; Yamazaki, Tomohiro; Ishida, Kasumi; Yagita, Kenji

    2015-02-05

    Here, we report the draft genome sequence of high-temperature-adapted Protochlamydia sp. strain HS-T3, an environmental chlamydia. This bacterium is an amoebal endosymbiont, found in Acanthamoeba isolated from a hot spring in Japan. Strain HS-T3 readily grew in mammalian cells at 37°C, a characteristic not previously reported for environmental chlamydiae.

  9. The fate of Helicobacter pylori phagocytized by Acanthamoeba polyphaga demonstrated by fluorescent in situ hybridization and quantitative polymerization chain reaction tests

    EPA Science Inventory

    Helicobacter pylori able to express green fluorescent protein, as well as an ATCC strain, and a clinical isolate of this pathogen were evaluated for their ability to survive predation by Acanthamoeba polyphaga. Ingestion was evaluated by microscopic observation of the GFP-H. pyl...

  10. In-depth study of Mollivirus sibericum, a new 30,000-y-old giant virus infecting Acanthamoeba.

    PubMed

    Legendre, Matthieu; Lartigue, Audrey; Bertaux, Lionel; Jeudy, Sandra; Bartoli, Julia; Lescot, Magali; Alempic, Jean-Marie; Ramus, Claire; Bruley, Christophe; Labadie, Karine; Shmakova, Lyubov; Rivkina, Elizaveta; Couté, Yohann; Abergel, Chantal; Claverie, Jean-Michel

    2015-09-22

    Acanthamoeba species are infected by the largest known DNA viruses. These include icosahedral Mimiviruses, amphora-shaped Pandoraviruses, and Pithovirus sibericum, the latter one isolated from 30,000-y-old permafrost. Mollivirus sibericum, a fourth type of giant virus, was isolated from the same permafrost sample. Its approximately spherical virion (0.6-µm diameter) encloses a 651-kb GC-rich genome encoding 523 proteins of which 64% are ORFans; 16% have their closest homolog in Pandoraviruses and 10% in Acanthamoeba castellanii probably through horizontal gene transfer. The Mollivirus nucleocytoplasmic replication cycle was analyzed using a combination of "omic" approaches that revealed how the virus highjacks its host machinery to actively replicate. Surprisingly, the host's ribosomal proteins are packaged in the virion. Metagenomic analysis of the permafrost sample uncovered the presence of both viruses, yet in very low amount. The fact that two different viruses retain their infectivity in prehistorical permafrost layers should be of concern in a context of global warming. Giant viruses' diversity remains to be fully explored. PMID:26351664

  11. In-depth study of Mollivirus sibericum, a new 30,000-y-old giant virus infecting Acanthamoeba.

    PubMed

    Legendre, Matthieu; Lartigue, Audrey; Bertaux, Lionel; Jeudy, Sandra; Bartoli, Julia; Lescot, Magali; Alempic, Jean-Marie; Ramus, Claire; Bruley, Christophe; Labadie, Karine; Shmakova, Lyubov; Rivkina, Elizaveta; Couté, Yohann; Abergel, Chantal; Claverie, Jean-Michel

    2015-09-22

    Acanthamoeba species are infected by the largest known DNA viruses. These include icosahedral Mimiviruses, amphora-shaped Pandoraviruses, and Pithovirus sibericum, the latter one isolated from 30,000-y-old permafrost. Mollivirus sibericum, a fourth type of giant virus, was isolated from the same permafrost sample. Its approximately spherical virion (0.6-µm diameter) encloses a 651-kb GC-rich genome encoding 523 proteins of which 64% are ORFans; 16% have their closest homolog in Pandoraviruses and 10% in Acanthamoeba castellanii probably through horizontal gene transfer. The Mollivirus nucleocytoplasmic replication cycle was analyzed using a combination of "omic" approaches that revealed how the virus highjacks its host machinery to actively replicate. Surprisingly, the host's ribosomal proteins are packaged in the virion. Metagenomic analysis of the permafrost sample uncovered the presence of both viruses, yet in very low amount. The fact that two different viruses retain their infectivity in prehistorical permafrost layers should be of concern in a context of global warming. Giant viruses' diversity remains to be fully explored.

  12. [The effect of silica on the development of experimental Acanthamoeba meningoencephalitis with reference to the macrophage role in mice].

    PubMed

    Lee, H S; Shin, H J; La, M S; Im, K

    1994-12-01

    The role of macrophages was observed in intranasally infected C3H/HeJ mice with trophozoites (3 x 10(5)) of Acanthamoeba culbertsoni which was a kind of free-living amoebae inducing meningoencephalitis in human and experimental animals. The mortality was 60% in the group of intraperitoneally injected mice with silica (0.5 mg/0.5 ml). It was much higher than that of 10% in the group of amoeba infected mice without silica administration. The phagocytic index of peritoneal macrophages co-cultured with Toxoplasma gondii was estimated daily. In contrast to the control and amoeba infected group which didn't show significant fluctuation of the phagocytic indices, the silica administrated group revealed under 3% until day 3, and gradual increase up to 24.7% in day 5 which was same level of amoeba infected group without silica administration. The level of interleukin-1b (IL-1b) measured by ELISA was the highest in the amoeba infected group without silica injection and the lowest in the amoeba infected group with silica administration. In the test of the amoebicidal activity of mice peritoneal macrophages in vitro, silica administration revealed reducing effect on amoebicidal activity of macrophages. In conclusion, macrophages were proven to play a significant role in defense mechanism against the development of experimentally induced Acanthamoeba meningoencephalitis. PMID:7834243

  13. Morphological characteristics of developmental stages of Acanthamoeba and Naegleria species before and after staining by various techniques.

    PubMed

    Ithoi, Init; Ahmad, Arine-Fadzlun; Mak, J W; Nissapatorn, Veeranoot; Lau, Yee-Ling; Mahmud, Rohela

    2011-11-01

    Seven stains were studied to determine the best color and contrast for staining the developmental stages of free living pathogenic Acanthamoeba and Naegleria species. The acid-fast bacilli stain (AFB) produced a blue color without contrast; trichrome-eosin and modified Field's showed various color contrasts; Giemsa, iron-hematoxylin, modified AFB and Gram produced only one color which distinguished the nucleus, nucleolus, cytoplasm, food- and water-vacuoles. The motile organs (acanthopodia, pseudopodia, lobopodia and flagella) were also clearly differentiated but produced a similar color as the cytoplasm. These motile organelles were first induced by incubating at 37 degrees C for at least 15 minutes and then fixing with methanol in order to preserve the protruding morphology prior to staining. The trichrome-eosin and iron-hematoxylin stains showed good color contrast for detecting all three stages, the trophozoite, cyst and flagellate; Giemsa and Gram stained the trophozoite and flagellate stages; the modified Field's and modified AFB stains stained only the trophozoite stage. Depending on the purpose, all these stains (except the AFB stain) can be used to identify the developmental stages of Acanthamoeba and Naegleria for clinical, epidemiological or public health use.

  14. In-depth study of Mollivirus sibericum, a new 30,000-y-old giant virus infecting Acanthamoeba

    PubMed Central

    Legendre, Matthieu; Lartigue, Audrey; Bertaux, Lionel; Jeudy, Sandra; Bartoli, Julia; Lescot, Magali; Alempic, Jean-Marie; Ramus, Claire; Bruley, Christophe; Labadie, Karine; Shmakova, Lyubov; Rivkina, Elizaveta; Couté, Yohann; Abergel, Chantal; Claverie, Jean-Michel

    2015-01-01

    Acanthamoeba species are infected by the largest known DNA viruses. These include icosahedral Mimiviruses, amphora-shaped Pandoraviruses, and Pithovirus sibericum, the latter one isolated from 30,000-y-old permafrost. Mollivirus sibericum, a fourth type of giant virus, was isolated from the same permafrost sample. Its approximately spherical virion (0.6-µm diameter) encloses a 651-kb GC-rich genome encoding 523 proteins of which 64% are ORFans; 16% have their closest homolog in Pandoraviruses and 10% in Acanthamoeba castellanii probably through horizontal gene transfer. The Mollivirus nucleocytoplasmic replication cycle was analyzed using a combination of “omic” approaches that revealed how the virus highjacks its host machinery to actively replicate. Surprisingly, the host’s ribosomal proteins are packaged in the virion. Metagenomic analysis of the permafrost sample uncovered the presence of both viruses, yet in very low amount. The fact that two different viruses retain their infectivity in prehistorical permafrost layers should be of concern in a context of global warming. Giant viruses’ diversity remains to be fully explored. PMID:26351664

  15. Multiplex real-time PCR assay for simultaneous detection of Acanthamoeba spp., Balamuthia mandrillaris, and Naegleria fowleri.

    PubMed

    Qvarnstrom, Yvonne; Visvesvara, Govinda S; Sriram, Rama; da Silva, Alexandre J

    2006-10-01

    Infections caused by Naegleria fowleri, Acanthamoeba spp., and Balamuthia mandrillaris occur throughout the world and pose many diagnostic challenges. To date, at least 440 cases of severe central nervous system infections caused by these amebas have been documented worldwide. Rapid and specific identification of these free-living amebas in clinical samples is of crucial importance for efficient case management. We have developed a triplex real-time TaqMan PCR assay that can simultaneously identify Acanthamoeba spp., B. mandrillaris, and N. fowleri in the same PCR vessel. The assay was validated with 22 well-characterized amebic strains harvested from cultures and nine clinical specimens that were previously characterized by in vitro culture and/or immunofluorescence assay. The triplex assay demonstrated high specificity and a rapid test completion time of less than 5 h from the reception of the specimen in the laboratory. This assay was able to detect one single ameba per sample analyzed, as determined with cerebrospinal fluid spiked with diluted cultured amebas. This assay could become useful for fast laboratory diagnostic assessment of amebic infections (caused by free-living amebas) in laboratories with adequate infrastructure to perform real-time PCR testing.

  16. Acanthamoeba castellanii Genotype T4 Stimulates the Production of Interleukin-10 as Well as Proinflammatory Cytokines in THP-1 Cells, Human Peripheral Blood Mononuclear Cells, and Human Monocyte-Derived Macrophages.

    PubMed

    Mattana, Antonella; Sanna, Manuela; Cano, Antonella; Delogu, Giuseppe; Erre, Giuseppe; Roberts, Craig W; Henriquez, Fiona L; Fiori, Pier Luigi; Cappuccinelli, Piero

    2016-10-01

    Free-living amoebae of the genus Acanthamoeba can cause severe and chronic infections in humans, mainly localized in immune privileged sites, such as the brain and the eye. Monocytes/macrophages are thought to be involved in Acanthamoeba infections, but little is known about how these facultative parasites influence their functions. The aim of this work was to investigate the effects of Acanthamoeba on human monocytes/macrophages during the early phase of infection. Here, THP-1 cells, primary human monocytes isolated from peripheral blood, and human monocyte-derived macrophages were either coincubated with trophozoites of a clinical isolate of Acanthamoeba (genotype T4) or stimulated with amoeba-derived cell-free conditioned medium. Production of proinflammatory cytokines (tumor necrosis factor alpha [TNF-α], interleukin-6 [IL-6], and IL-12), anti-inflammatory cytokine (IL-10), and chemokine (IL-8) was evaluated at specific hours poststimulation (ranging from 1.5 h to 23 h). We showed that both Acanthamoeba trophozoites and soluble amoebic products induce an early anti-inflammatory monocyte-macrophage phenotype, characterized by significant production of IL-10; furthermore, challenge with either trophozoites or their soluble metabolites stimulate both proinflammatory cytokines and chemokine production, suggesting that this protozoan infection results from the early induction of coexisting, opposed immune responses. Results reported in this paper confirm that the production of proinflammatory cytokines and chemokines by monocytes and macrophages can play a role in the development of the inflammatory response during Acanthamoeba infections. Furthermore, we demonstrate for the first time that Acanthamoeba stimulates IL-10 production in human innate immune cells, which might both promote the immune evasion of Acanthamoeba and limit the induced inflammatory response. PMID:27481240

  17. Acanthamoeba castellanii Genotype T4 Stimulates the Production of Interleukin-10 as Well as Proinflammatory Cytokines in THP-1 Cells, Human Peripheral Blood Mononuclear Cells, and Human Monocyte-Derived Macrophages

    PubMed Central

    Sanna, Manuela; Cano, Antonella; Delogu, Giuseppe; Erre, Giuseppe; Roberts, Craig W.; Henriquez, Fiona L.; Fiori, Pier Luigi; Cappuccinelli, Piero

    2016-01-01

    Free-living amoebae of the genus Acanthamoeba can cause severe and chronic infections in humans, mainly localized in immune privileged sites, such as the brain and the eye. Monocytes/macrophages are thought to be involved in Acanthamoeba infections, but little is known about how these facultative parasites influence their functions. The aim of this work was to investigate the effects of Acanthamoeba on human monocytes/macrophages during the early phase of infection. Here, THP-1 cells, primary human monocytes isolated from peripheral blood, and human monocyte-derived macrophages were either coincubated with trophozoites of a clinical isolate of Acanthamoeba (genotype T4) or stimulated with amoeba-derived cell-free conditioned medium. Production of proinflammatory cytokines (tumor necrosis factor alpha [TNF-α], interleukin-6 [IL-6], and IL-12), anti-inflammatory cytokine (IL-10), and chemokine (IL-8) was evaluated at specific hours poststimulation (ranging from 1.5 h to 23 h). We showed that both Acanthamoeba trophozoites and soluble amoebic products induce an early anti-inflammatory monocyte-macrophage phenotype, characterized by significant production of IL-10; furthermore, challenge with either trophozoites or their soluble metabolites stimulate both proinflammatory cytokines and chemokine production, suggesting that this protozoan infection results from the early induction of coexisting, opposed immune responses. Results reported in this paper confirm that the production of proinflammatory cytokines and chemokines by monocytes and macrophages can play a role in the development of the inflammatory response during Acanthamoeba infections. Furthermore, we demonstrate for the first time that Acanthamoeba stimulates IL-10 production in human innate immune cells, which might both promote the immune evasion of Acanthamoeba and limit the induced inflammatory response. PMID:27481240

  18. Effects of harmful cyanobacteria on the freshwater pathogenic free-living amoeba Acanthamoeba castellanii.

    PubMed

    Urrutia-Cordero, Pablo; Agha, Ramsy; Cirés, Samuel; Lezcano, María Ángeles; Sánchez-Contreras, María; Waara, Karl-Otto; Utkilen, Hans; Quesada, Antonio

    2013-04-15

    Grazing is a major regulating factor in cyanobacterial population dynamics and, subsequently, considerable effort has been spent on investigating the effects of cyanotoxins on major metazoan grazers. However, protozoan grazers such as free-living amoebae can also feed efficiently on cyanobacteria, while simultaneously posing a major threat for public health as parasites of humans and potential reservoirs of opportunistic pathogens. In this study, we conducted several experiments in which the freshwater amoeba Acanthamoeba castellanii was exposed to pure microcystin-LR (MC-LR) and six cyanobacterial strains, three MC-producing strains (MC-LR, MC-RR, MC-YR, MC-WR, [Dha7] MC-RR) and three strains containing other oligopeptides such as anabaenopeptins and cyanopeptolins. Although the exposure to high concentrations of pure MC-LR yielded no effects on amoeba, all MC-producing strains inflicted high mortality rates on amoeba populations, suggesting that toxic effects must be mediated through the ingestion of toxic cells. Interestingly, an anabaenopeptin-producing strain caused the greatest inhibition of amoeba growth, indicating that toxic bioactive compounds other than MCs are of great importance for amoebae grazers. Confocal scanning microscopy revealed different alterations in amoeba cytoskeleton integrity and as such, the observed declines in amoeba densities could have indeed been caused via a cascade of cellular events primarily triggered by oligopeptides with protein-phosphatase inhibition capabilities such as MCs or anabaenopeptins. Moreover, inducible-defense mechanisms such as the egestion of toxic, MC-producing cyanobacterial cells and the increase of resting stages (encystation) in amoebae co-cultivated with all cyanobacterial strains were observed in our experiments. Consequently, cyanobacterial strains showed different susceptibilities to amoeba grazing which were possibly influenced by the potentiality of their toxic secondary metabolites. Hence, this

  19. Multiplication of different Legionella species in Mono Mac 6 cells and in Acanthamoeba castellanii.

    PubMed Central

    Neumeister, B; Schöniger, S; Faigle, M; Eichner, M; Dietz, K

    1997-01-01

    Survival and distribution of legionellae in the environment are assumed to be associated with their multiplication in amoebae, whereas the ability to multiply in macrophages is usually regarded to correspond to pathogenicity. Since most investigations focused on Legionella pneumophila serogroup 1, we examined the intracellular multiplication of different Legionella species in Mono Mac 6 cells, which express phenotypic and functional features of mature monocytes, and in Acanthamoeba castellanii, an environmental host of Legionella spp. According to the bacterial doubling time in Mono Mac 6 cells and in A. castellanii, seven clusters of legionellae could be defined which could be split further with regard to finer differences. L. longbeachae serogroup 1, L. jordanis, and L. anisa were not able to multiply in either A. castellanii or Mono Mac 6 cells and are members of the first cluster. L. dumoffi did not multiply in Mono Mac 6 cells but showed a delayed multiplication in A. castellanii 72 h after infection and is the only member of the second cluster. L. steigerwaltii, L. gormanii, L. pneumophila serogroup 6 ATCC 33215, L. bozemanii, and L. micdadei showed a stable bacterial count in Mono Mac 6 cells after infection but a decreasing count in amoebae. They can be regarded as members of the third cluster. As the only member of the fourth cluster, L. oakridgensis was able to multiply slight in Mono Mac 6 cells but was killed within amoebae. A strain of L. pneumophila serogroup 1 Philadelphia obtained after 30 passages on SMH agar and a strain of L. pneumophila serogroup 1 Philadelphia obtained after intraperitoneal growth in guinea pigs are members of the fifth cluster, which showed multiplication in Mono Mac 6 cells but a decrease of bacterial counts in A. castellanii. The sixth cluster is characterized by intracellular multiplication in both host cell systems and consists of several strains of L. pneumophila serogroup 1 Philadelphia, a strain of L. pneumophila

  20. Acanthamoeba castellanii of the T4 genotype is a potential environmental host for Enterobacter aerogenes and Aeromonas hydrophila

    PubMed Central

    2013-01-01

    Background Acanthamoeba can interact with a wide range of microorganisms such as viruses, algae, yeasts, protists and bacteria including Legionella pneumophila, Pseudomonas aeruginosa, Vibrio cholerae, Helicobacter pylori, Listeria monocytogenes, Mycobacterium spp., and Escherichia coli. In this capacity, Acanthamoeba has been suggested as a vector in the transmission of bacterial pathogens to the susceptible hosts. Methods Here, we used a keratitis isolate of A. castellanii of the T4 genotype and studied its interactions with two bacterial genera which have not been tested before, Enterobacter aerogenes, and Aeromonas hydrophila, as well as E. coli. Assays were performed to determine bacterial association with and invasion of A. castellanii. Additionally, bacterial survival intracellular of A. castellanii trophozoites as well as cysts was determined. Results All three bacterial isolates tested, associated, invaded, and survived inside A. castellanii trophozoites as well as A. castellanii cysts. However, E. aerogenes and E. coli exhibited significantly reduced association with and invasion of A. castellanii as compared with A. hydrophila (P < 0.01 using paired T-test, one tail distribution). In the long term survival assays, all three bacterial isolates tested remained viable inside A. castellanii trophozoites, while amoeba remained intact; however A. hydrophila exhibited higher survival inside amoebae (14.54 ± 3.3 bacteria:amoeba ratio) compared with E. aerogenes (3.96 ± 0.7 bacteria:amoeba ratio) and E. coli (5.85 ± 1.1 bacteria:amoeba ratio). A. hydrophila, E. coli, and E. aerogenes remained viable during the encystment process and exhibited higher levels of recovery from mature cysts (14.13 ± 0.89 A. hydrophila:amoeba ratio, 10.13 ± 1.17 E. aerogenes:amoeba ratio, and 11.95 ± 0.7 E. coli:amoeba ratio). Conclusions A. hydrophila and E. aerogenes also joined the ranks of other bacteria that could benefit from A. castellanii