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J. Howe - One of the best experts on this subject based on the ideXlab platform.

  • Scanning electron microscopy of the surface coat of Blastocystis Hominis.
    Parasitology research, 1999
    Co-Authors: V. Zaman, J. Howe, T. K. Goh
    Abstract:

    Scanning electron microscopy of Blastocystis Hominis showed that its outer coat has a fibrillar structure and individual fibrils may extend up to 5 μm from the periphery of the parasite. The surface coat remains intact during cell division. Bacteria are often seen adhering to it, but for the first time a trophozoite of Chilomastix mesnili was also seen in this position. It is postulated that breakdown of attached organisms may provide nutrients for Blastocystis.

  • Postcystic development of Blastocystis Hominis.
    Parasitology research, 1999
    Co-Authors: V. Zaman, Mehreen Zaki, M. Manzoor, J. Howe
    Abstract:

    A concentrated suspension of Blastocystis Hominis cysts was inoculated into Jones' medium and removed after 24 h for study of their development at the ultrastructural level. The parasite divides in the cyst, and up to three daughter cells can be seen. During this process the cyst wall dissolves, leaving behind thin membranous remnants. Excystation occurs mostly by the emergence of the daughter cells through an aperture in the outer fibrillar coat. Before excystation the vacuolar and the granular stages form and the daughter cells develop their own fibrillar layer.

  • Development of Blastocystis Hominis cysts into vacuolar forms in vitro.
    Parasitology research, 1999
    Co-Authors: K. T. Moe, J. Howe, Mulkit Singh, S. W. Tan, X. Q. Chen, Eu-hian Yap
    Abstract:

    The development of cysts of Blastocystis Hominis isolated from human feces by the Ficoll-Paque concentration method and cultured in Jones' medium containing 10% horse serum is described. The morphological changes were studied by light and transmission electron microscopy at different intervals for up to 48 h. The cysts developed into a large number of vacuolar forms within 24 h, and binary fission was the only mode of reproduction observed.

  • Scanning electron microscopy of Blastocystis Hominis cysts
    Parasitology research, 1998
    Co-Authors: V. Zaman, J. Howe
    Abstract:

    Scanning electron microscopy of Blastocystis Hominis cysts reveals that some cysts have an outer coat, whereas others are naked. If intact, the outer coat forms a fan-like structure around the cyst and its surface is granular. The fragmented outer coat adheres to other cysts and bacteria, forming irregular clumps.

  • experimental Blastocystis Hominis infection in laboratory mice
    Parasitology Research, 1997
    Co-Authors: K. T. Moe, J. Howe, S. W. Tan, X. Q. Chen, M Singh, E H Yap
    Abstract:

    Young (less than 8 weeks old) immunocompetent BALB/c mice became infected with Blastocystis Hominis after inoculation of fecal cysts orally and of in vitro axenic-culture forms intracecally. This study confirmed that the fecal cyst was the form responsible for external transmission and that the mode of transmission was by the fecal-oral route. The infection was self-limiting and the infected BALB/c mice appeared normal except that some of them showed weight loss and lethargy. Both vacuolar and granular forms were found in the cecum, but only cyst forms were observed in the colon. Histological examination of the cecum and colon showed intense inflammatory-cell infiltration, edematous lamina propria, and mucosal sloughing. It is apparent that although B. Hominis is not invasive, it is capable of causing pathogenesis in BALB/c mice.

V. Zaman - One of the best experts on this subject based on the ideXlab platform.

  • Resistance of Blastocystis Hominis cysts to metronidazole.
    Tropical medicine & international health : TM & IH, 2007
    Co-Authors: V. Zaman, M. Zaki
    Abstract:

    Blastocystis Hominis cysts concentrated from faeces were resistant to metronidazole up to a concentration of 5 mg/ml. A cysticidal drug is therefore needed for radical treatment, to avoid relapse and to prevent transmission.

  • Scanning electron microscopy of the surface coat of Blastocystis Hominis.
    Parasitology research, 1999
    Co-Authors: V. Zaman, J. Howe, T. K. Goh
    Abstract:

    Scanning electron microscopy of Blastocystis Hominis showed that its outer coat has a fibrillar structure and individual fibrils may extend up to 5 μm from the periphery of the parasite. The surface coat remains intact during cell division. Bacteria are often seen adhering to it, but for the first time a trophozoite of Chilomastix mesnili was also seen in this position. It is postulated that breakdown of attached organisms may provide nutrients for Blastocystis.

  • Postcystic development of Blastocystis Hominis.
    Parasitology research, 1999
    Co-Authors: V. Zaman, Mehreen Zaki, M. Manzoor, J. Howe
    Abstract:

    A concentrated suspension of Blastocystis Hominis cysts was inoculated into Jones' medium and removed after 24 h for study of their development at the ultrastructural level. The parasite divides in the cyst, and up to three daughter cells can be seen. During this process the cyst wall dissolves, leaving behind thin membranous remnants. Excystation occurs mostly by the emergence of the daughter cells through an aperture in the outer fibrillar coat. Before excystation the vacuolar and the granular stages form and the daughter cells develop their own fibrillar layer.

  • Scanning electron microscopy of Blastocystis Hominis cysts
    Parasitology research, 1998
    Co-Authors: V. Zaman, J. Howe
    Abstract:

    Scanning electron microscopy of Blastocystis Hominis cysts reveals that some cysts have an outer coat, whereas others are naked. If intact, the outer coat forms a fan-like structure around the cyst and its surface is granular. The fragmented outer coat adheres to other cysts and bacteria, forming irregular clumps.

  • The diagnosis of Blastocystis Hominis cysts in human faeces.
    The Journal of infection, 1996
    Co-Authors: V. Zaman
    Abstract:

    Blastocystis Hominis cysts in faeces can be concentrated on Ficoll column. They are pleomorphic in shape having a mean diameter of 6.65 μm (s.d. = 2.32). They may or may not have a membranous layer surrounding them. The membranous layer tends to come off with pressure or dying of the specimen and corresponds to the fibrillar layer observed under the electron microscope. The Ficoll concentration technique is also useful for concentrating other protozoan cysts.

P. F. L. Boreham - One of the best experts on this subject based on the ideXlab platform.

  • Blastocystis Hominis revisited.
    Clinical microbiology reviews, 1996
    Co-Authors: D.j. Stenzel, P. F. L. Boreham
    Abstract:

    Blastocystis Hominis is a unicellular organism found commonly in the intestinal tract of humans and many other animals. Very little is known of the basic biology of the organism, and controversy surrounds its taxonomy and pathogenicity. There morphological forms (vacuolar, granular, and ameboid) have been recognized, but recent studies have revealed several additional forms (cyst, avacuolar, and multivacuolar). The biochemistry of the organism has not been studied to any extent, and organelles and structures of unknown function and composition are present in the cells. Several life cycles have been proposed but not experimentally validated. The form used for transmission has not been defined. Infections with the organism are worldwide and appear in both immunocompetent and immunodeficient individuals. Symptoms generally attributed to B. Hominis infection are nonspecific, and the need for treatment is debated. If treatment appears warranted, metronidazole is suggested as the drug of choice, although failures of this drug in eradicating the organism have been reported. Infection is diagnosed by light microscopic examination of stained smears or wet mounts of fecal material. Most laboratories identify B. Hominis by observing the vacuolar form, although morphological studies indicate that other forms, such as the cyst form and multivacuolar form, also should be sought for diagnosis.

  • protein and dna evidence for two demes of Blastocystis Hominis from humans
    International Journal for Parasitology, 1992
    Co-Authors: P. F. L. Boreham, J.a. Upcroft, Linda A. Dunn
    Abstract:

    Analysis of 10 stocks of Blastocystis Hominis isolated from human stools revealed two discrete groups of organisms. Proteins of the two groups were immunologically distinct and hybridization with random probes generated from the DNA of one stock showed that the DNA content of the two groups was different. Further studies are required to determine whether these should be classified as discrete species or whether these groups are epidemiologically significant.

  • The in-vitro activity of drugs against Blastocystis Hominis
    Journal of Antimicrobial Chemotherapy, 1991
    Co-Authors: Linda A. Dunn, P. F. L. Boreham
    Abstract:

    : The development of an assay to measure the sensitivity of drugs against Blastocystis Hominis using the incorporation of 3H-hypoxanthine is described. The activity of 42 compounds have been measured. Four of the 5-nitroimidazoles tested (satranidazole, S75 0400 A, flunidazole and ronidazole) were found to be more active than metronidazole, the drug commonly used to treat infections caused by B. Hominis in humans. Other potentially useful compounds include emetine, furazolidone and quinacrine. Ketoconazole and iodoquinol reported to have therapeutic activity in infections caused by this parasite were found to be significantly less active than metronidazole.

Giorgio Scalise - One of the best experts on this subject based on the ideXlab platform.

  • Irritable Bowel Syndrome in Patients with Blastocystis Hominis Infection
    European Journal of Clinical Microbiology & Infectious Diseases, 1999
    Co-Authors: Andrea Giacometti, Marek Fortuna, Adriana Fiorentini, Oscar Cirioni, Giorgio Scalise
    Abstract:

    The prevalence of Blastocystis Hominis in stool specimens of individuals with gastrointestinal symptoms was evaluated to study a possible link between the protozoan and the irritable bowel syndrome. According to the Rome diagnostic criteria, 388 patients were evaluated. Altogether, 81 patients were classified as affected by irritable bowel syndrome. Blastocystis Hominis was recovered from the stools of 38 subjects, 15 of whom belonged to the group with irritable bowel syndrome (P=0.006). In addition, patients with irritable bowel syndrome were significantly more likely to have five or more Blastocystis Hominis organisms per field (P=0.031). In conclusion, there was a set of patients with irritable bowel syndrome in whom the presence of Blastocystis Hominis may not be incidental.

Mulkit Singh - One of the best experts on this subject based on the ideXlab platform.

  • Development of Blastocystis Hominis cysts into vacuolar forms in vitro.
    Parasitology research, 1999
    Co-Authors: K. T. Moe, J. Howe, Mulkit Singh, S. W. Tan, X. Q. Chen, Eu-hian Yap
    Abstract:

    The development of cysts of Blastocystis Hominis isolated from human feces by the Ficoll-Paque concentration method and cultured in Jones' medium containing 10% horse serum is described. The morphological changes were studied by light and transmission electron microscopy at different intervals for up to 48 h. The cysts developed into a large number of vacuolar forms within 24 h, and binary fission was the only mode of reproduction observed.

  • Colony formation of Blastocystis Hominis in soft agar
    Parasitology research, 1996
    Co-Authors: S. W. Tan, Mulkit Singh, Eu-hian Yap, K. T. Moe, J. Howe
    Abstract:

    This is the first description of a method for growing axenized Blastocystis Hominis as colonies in petri dishes containing soft agar. Blastocystis cells cultured in two types of agar appeared to show different colonial morphologies as well as differing colony yields. Microscopic examination of the colonies revealed many amoeboid and giant cells. Many cells were also shown to possess thin filament-like structures that appeared to stretch across the central vacuole.

  • Tubulovesicular elements in Blastocystis Hominis from the caecum of experimentally-infected rats
    International journal for parasitology, 1995
    Co-Authors: K. Suresh, J. Howe, Eu-hian Yap, S. Y. Chong, Mulkit Singh
    Abstract:

    By transmission electron microscopy (TEM), tubulovesicular elements were seen in Blastocystis Hominis obtained from the caecum of experimentally-infected rats. These appeared to arise from the peripheral cytoplasm and were rounded, oval or elongate in sections. It is suggested that these elements form a network for transfer of nutrients to the periphery during the process of encystation.

  • A multiple fission-like mode of asexual reproduction in Blastocystis Hominis
    Parasitology research, 1994
    Co-Authors: K. Suresh, J. Howe, N. P. Ramachandran, A. K. Loh, Eu-hian Yap, Mulkit Singh
    Abstract:

    A non-axenic and an axenic isolate of Blastocystis Hominis have been induced to form cysts in vitro using an encystation medium. The morphology of the parasite at different time points was observed by scanning electron microscopy. In day-2 cultures the cysts were spherical and had a non-uniform, coarse outer surface around the body. A deep, pore-like opening was seen in some of the parasites. Most of the cysts from day-4 and day-6 cultures ruptured, revealing small, uniformly sized spherical bodies occurring in grape-like clusters. Acridine orange staining confirmed that these bodies were the progeny of Blastocystis Hominis. A multiple fission-like reproduction process giving rise to many daughter Blastocystis occurs within the cyst.