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Biomedical subjects

E U Canning

Publications and source records attributed to E U Canning.

At least 37 records · Page 2Linked to original sources
PubMed1997

Monoclonal antibodies against Babesia caballi and Babesia equi and their application in serodiagnosis.

The production of monoclonal antibodies to the bloodstages of the haemoprotozoan parasites Babesia caballi and Babesia equi and the characterization of their corresponding antigens are described. Species specific and immunogenic proteins of both parasites were identified using SDS-PAGE, Western blotting and ELISA. These proteins were then electroeluted from SDS-PAGE gels and used to immunize BALB/c mice for hybridoma production. One monoclonal antibody (Mab), designated BC5.37.70.27 (BC5), recognized a 70 kDa protein of B. caballi as demonstrated by Western blotting under reducing conditions. Another Mab, BE1.24/2.95 (BEI), recognized a 34 kDa protein of B. equi. Both Mabs reacted specifically in indirect ELISA when isolated whole merozoites were used as antigen. Preliminary studies using the two Mabs in a competitive ELISA (cELISA) suggest that the cELISA for the detection of B. caballi infection is more sensitive than the commonly used complement fixation test but that refinement is necessary for the B. equi system.

Animals↗
PubMed1996

Development and ultrastructure of Trachipleistophora hominis n.g., n.sp. after in vitro isolation from an AIDS patient and inoculation into athymic mice.

Continuous culture was achieved in several cell lines of a microsporidium obtained from the skeletal muscle of an AIDS patient. Development in COS-1 and RK13 cells was prolific. Spores from the original biopsy were also inoculated into athymic mice by i.m. and i.p. routes. Infection was found in several organs as well as in skeletal muscle after a few weeks. All stages were surrounded by an electron-dense surface coat. Meronts had 2-4 nuclei and divided by binary fission. In sporogony the surface coat became separated from the plasma membrane to form a sporophorous vesicle, within which division into sporoblasts was effected by repeated binary fissions. The number of sporoblasts (and later spores) within the sporophorous vesicles varied from 2 to > 32 and the sizes of the vesicles varied, according to the number of spores contained therein, from 5 microns diameter to 14.0 x 11.0 microns. Spores measured 4.0 x 2.4 microns and had a prominent posterior vacuole. The parasite differs from the genus Pleistophora in that it does not form multinucleate sporogonial plasmodia and that the sporophorous vesicle enlarges during sporogony and its wall is not a multilayered structure. It is proposed to place it in a new genus and species Trachipleistophora hominis n.g., n.sp.

AIDS-Related Opportunistic Infections↗
PubMed1996

Myositis associated with a newly described microsporidian, Trachipleistophora hominis, in a patient with AIDS.

Microsporidia are zoonotic protozoa which were rare human pathogens prior to 1985, when Enterocytozoon bieneusi was described in human immunodeficiency virus-infected patients with chronic diarrhea. Another species, Encephalitozoon (Septata) intestinalis, is associated with diarrhea and chronic sinusitis, and approximately 25 cases have been reported in the literature. However, other microsporidial infections in human immunodeficiency virus-infected patients remain extremely rare. We report the first case of a Pleistophora sp.-like microsporidian infection presenting as a progressive severe myosotis associated with fever and weight loss. The organism was demonstrated by light microscopy and electron microscopy in corneal scrapings, skeletal muscle, and nasal discharge. Electron microscopy showed an electron-dense surface coat with "sunflare"-like projections surrounding all stages of development of meronts (two to four nuclei, dividing by binary fission), sporonts, and sporoblasts. Division of sporonts, in which sporonts separate from the thick outer coat, creating a sporophorous vesicle, is by binary fission, differentiating this organism from Pleistophora sp. The spore measures 4.0 by 2.5 microns and has a rugose exospore. A new genus and species, Trachipleistophora hominis, has been established for this parasite. The patient was treated with albendazole, sulfadiazine, and pyrimethamine, and the clinical symptoms resolved.

AIDS-Related Opportunistic Infections↗
PubMed1995

In vitro cultivation of the human microsporidium Vittaforma corneae: development and effect of albendazole.

When in vitro growth of Vittaforma corneae was tested using MDCK, MRC-5, XEN, L-929 and FHM cell lines, propagation occurred only in MDCK, MRC-5 and XEN cells. The intervals required for the various stages of the life cycle to develop were the same in all the cell lines tested. The MDCK cell line was selected to support the growth of V. corneae in vitro and provide the system for in vitro testing of drugs. The weekly output of V. corneae spores from the MDCK cell monolayer was monitored over a 61-week period during which there were fluctuations but no definite increase or decrease in output. Albendazole at 2.1 or 4.2 micrograms/ml in MEM was tested against V. corneae in MDCK cell monolayers and showed antimicrosporidial activity. The percentage of infected cells was reduced in the presence of the drug and there were ultrastructural abnormalities in all stages of the life cycle. The drug prevents parasite division.

Albendazole↗
PubMed1994

Septata intestinalis frequently isolated from stool of AIDS patients with a new cultivation method.

Two species of microsporidia, Enterocytozoon bieneusi and Septata intestinalis have been reported as intestinal parasites of AIDS patients. In attempts to establish E. bieneusi in vitro, spores were concentrated from stool samples from 4 AIDS patients with biopsy-proven E. bieneusi infections. After sterilization of the concentrate in antibiotic solution, the spores were added to monolayers of RK13 cells grown on the membranes of Transwells. Cultures were established from 7 stool samples from the 4 patients but in every case the species established was S. intestinalis not E. bieneusi. On retrospective examination of the stools, a very small number of spores of a size comparable to that of S. intestinalis was found but this species was not detected in biopsies. Typical septate vacuoles containing Type I tubules were observed in vitro but in contrast to the original description, meronts were intravacuolar and sporogony was mainly disporoblastic. The cultivation system, used for the first time for microsporidia, revealed the presence of unsuspected S. intestinalis infections and indicates that this species may be much more common than hitherto suspected. S. intestinalis has not previously been cultured.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Reversible renal failure caused by a microsporidian infection.

OBJECTIVE: To report a case of renal failure associated with microsporidian infection in an HIV-seropositive patient. DESIGN: Case report. SETTING: Chelsea and Westminster Hospital, London, England, UK. PATIENT: An HIV-seropositive patient presented febrile with abdominal pain who developed renal failure. Renal biopsy and urinalysis showed infection with a microsporidian of the genus Encephalitozoon. INTERVENTION: Treatment with albendazole (400 mg) twice daily was associated with disappearance of infection from the urine, clinical improvement and return of renal function virtually to normal. CONCLUSION: HIV-seropositive individuals with renal failure should have urine screened for microsporidia. The administration of albendazole in such cases may reverse renal failure.

AIDS-Related Opportunistic Infections↗
PubMed1993

The antimicrosporidial activity of albendazole.

The antimicrosporidial activity of albendazole was tested on Nosema bombycis in vitro in Spodoptera frugiperda cells and in vivo in Heliocoverpa zea larvae and pupae. Significant reductions in the percentage of infected S. frugiperda cells were obtained using a concentration of 5.3 micrograms/ml albendazole in tissue culture medium but recrudescence occurred after the drug was withdrawn from the cultures. Significant reductions in the number of spores harvested from 6th-instar larvae or pupae were obtained when doses of 0.2 to 4.0 mg were incorporated into the diet but, with the lower doses, some resurgence of infection occurred in pupae after cessation of drug intake. Established infections were almost eliminated from 6th-instar larvae and pupae after consumption of 2 or 4 mg albendazole and infections were not established at all when 4 mg was consumed concurrently with the infective spores. Even at the highest dose albendazole had no deleterious effect on the growth and viability of H. zea. Clumped chromatin in the nuclei of meronts, revealed by electron microscopy, reflected the selective anti-tubulin activity of albendazole and there was massive disorganization of sporogonic development.

Albendazole↗
PubMed1993

Human microsporidiosis.

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AIDS-Related Opportunistic Infections↗
PubMed1993

Characterization of Encephalitozoon hellem (Microspora) isolated from the nasal mucosa of a patient with AIDS.

A microsporidium of the genus Encephalitozoon was isolated into culture from the nasal epithelium of a patient with AIDS. It was compared with in vitro isolates of Encephalitozoon cuniculi and the type isolate of Encephalitozoon hellem by SDS-PAGE and by Western blotting with murine antisera raised to E. cuniculi, E. hellem and the nasal isolate, monoclonal antibodies raised to E. cuniculi and sequential sera from the patient. All tests showed similarities between E. hellem and the nasal isolate but differences between these two isolates and E. cuniculi. Minor protein differences between E. hellem and the nasal isolate were not considered sufficient to separate them at the specific level. The new isolate is named the Wainwright isolate of E. hellem. The ultrastructure of the Wainwright isolate in vitro was similar to that of the parasite in vivo but there was a greater tendency for disruption of the parasitophorous vacuoles. The deposition of the electron-dense surface coat on the sporogonic stages of E. hellem, as a uniform layer which later thickens, is in contrast to its deposition as broad bands, which later join up, in E. cuniculi. This may be a useful character in distinguishing the species without recourse to analysis of protein profiles.

AIDS-Related Opportunistic Infections↗
PubMed1993

Experimental infection of athymic mice with the human microsporidian Nosema corneum.

Athymic mice (BALB/c nu/nu/Ola/Hsd) were experimentally infected intraperitoneally with Nosema corneum spores. Infection was monitored in the first and second weeks post-infection. The liver, spleen, kidney, intestine, lung, heart, brain and eye were collected. Quantification of infection in each organ using three different techniques gave approximately the same pattern of infection. Infection increased with time. Histological observations were made on the sites of infection in each organ. All organs were infected, the liver being the most heavily infected. The eye was infected in the retina in contrast to the cornea which was the site of infection in the original host. The present study of N. corneum in athymic mice has shown that this system could also be used to study host-parasite relationships and serve as a model for testing therapeutic agents. Previously the only microsporidian serving as a suitable model for human microsporidiosis was Encephalitozoon cuniculi.

Animals↗
PubMed1993

Diagnosis of intestinal and disseminated microsporidial infections in patients with HIV by a new rapid fluorescence technique.

AIMS: To assess the value of a new rapid fluorescence method for the diagnosis of microsporidiosis in HIV seropositive patients. METHODS: Microsporidian spores in stools were demonstrated by using the fluorochrome stain Uvitex 2B. The new technique was evaluated in three groups of HIV seropositive patients with diarrhoea. Group 1: 19 patients with biopsy confirmed E bieneusi infection (186 stool samples); group 2: 143 consecutive patients from whom faeces were submitted for routine investigation of diarrhoea (318 samples); group 3: 16 patients with small intestinal biopsy specimens negative for microsporidia (55 samples). The new method was used to monitor spore shedding during experimental treatment with paromomycin and albendazole in four patients. RESULTS: Brightly fluorescent spores were detected in all stool samples of patients in group 1. In group 2 16 (11%) patients had spores in their stool samples. E bieneusi was found in 11 patients; in the other five another genus of microsporidia, Encephalitozoon, was recognised. Encephalitozoon spores were also found in the urine of three of these patients and in the maxillary sinus aspirate of two of them, suggesting disseminated infection. The results were confirmed by electron microscopic examination. In group 3 negative biopsy specimens were confirmed by negative stool samples in all cases. Treatment with albendazole and paromomycin did not affect the spore shedding in three patients with E bieneusi infection. By contrast, in a patient with Encephalitozoon sp infection albendazole treatment resulted in clinical improvement together with complete cessation of spore excretion in the stool. CONCLUSION: The Uvitex 2B fluorescence method combines speed, sensitivity, and specificity for the diagnosis and treatment evaluation of intestinal and disseminated microsporidiosis.

Albendazole↗
PubMed1993

Staining of microsporidian spores by optical brighteners with remarks on the use of brighteners for the diagnosis of AIDS associated human microsporidioses.

Conditions for the effective fluorescence labelling of microsporidian spores by optical brighteners, based on the presence of chitin in the spore wall, are described. Spores of Vairimorpha ephestiae, V. necatrix, V. plodiae, Nosema bombycis, N. apis, N. algerae, Encephalitozoon cuniculi and Enterocytozoon bieneusi were examined. The degree of binding of Calcofluor White M2R (CFW) to untreated spores depends on the conditions and time of storage and the degree of bacterial contamination of the spore sample. Unpurified spores, stored in water are unreliable as control material for the estimation of CFW labelling. However, spores subjected to alkaline treatment by NaOH before CFW application are visualized with ease under all experimental conditions by their bright, not quenching fluorescence in shortwave light (approximately 350 nm) in CFW dilutions of 10(-4) or even lower. Similar improvement in labelling is achieved by exposing spores to CFW dissolved in 0.5-1N NaOH. As well as Calcofluor White M2R other optical brighteners (e.g. Uvitex 2B, Ciba-Geigy or Rylux BA, Ostacolor) can be used for labelling of spores.

AIDS-Related Opportunistic Infections↗
PubMed1991

Amblyospora sp. (Microspora, Amblyosporidae) infecting nerve ganglia of Culex pipiens (Diptera, Culicidae) from Egypt.

A species of Amblyospora-infecting neurones of Culex pipiens is described. Diplokaryotic meronts, which divided by binary fission, were distinguished at the electron microscope level by their unthickened plasma membranes. Sporonts with an electron-dense surface coat gave rise to eight uninucleate sporoblasts within a sporophorous vesicle, cytoplasmic division occurring at the quadrinucleate or octonucleate stages. Indications that nuclear fusion and chromosome reorganization occurred in merogony and sporogony were obtained by light microscopy but meiosis was not detected at the ultrastructural level. Spores were typical of Amblyospora, being ovoid when fresh, truncate when stained, and having an exospore of two membranous layers subtended by a thick amorphous layer, an electron-lucent endospore, an anisofilar polar filament, and a polaroplast comprised of an anterior region of close-packed lamellae and a posterior region of expanded sacs. The metabolic products in the sporophorous vesicle took the form of large globules, small globules with electron-dense borders, and fine granules. These were depleted in mature sporophorous vesicles, though a surface layer of fine granules on the spores may have been derived from them. Many stages were degenerate and it is suggested that C. pipiens may be an accidental host in which the parasite could develop suboptimally in nervous tissue only. Infections in larvae hatched from eggs in the laboratory indicate that vertical transmission occurs.

Animals↗
PubMed1991

Evidence for widespread occurrence of antibodies to Encephalitozoon cuniculi (Microspora) in man provided by ELISA and other serological tests.

The enzyme-linked immunosorbent assay (ELISA) was used to survey human sera for antibodies to Encephalitozoon cuniculi using spores obtained from in vitro cultures as antigen. Sera were obtained from patients with tropical diseases, neurological and renal disorders, patients who were HIV positive and those who had been tested for HIV but found to be negative. Sera from inhabitants of the village of Jali, The Gambia and from healthy blood donors were also examined. Numerous sera from all groups except the blood donors gave positive ELISA reactions at dilutions of 1:400. On titration, those with titres of 1:400 were reclassified as negative. Antibody titres of 1:800 and above were considered to be indicative of past or present infections with E. cuniculi. Many of these ELISA seropositives were also positive by IFAT or PAP. When examined by Western blotting of SDS-PAGE protein profiles of E. cuniculi spores, sera from many patients who had a tropical association reacted with the characteristic profiles shown by known positive mouse and rabbit sera. Others in the tropical group showed antibody binding to some but not all of the immunodominant polypeptides and yet others were negative in spite of their reactivity in the ELISA, IFAT or PAP test. Less agreement between ELISA and Western blotting results was obtained with the other groups of patients, although reactivity with one or more of the major polypeptide bands was sometimes seen. Serum from one blood donor, examined by ELISA and Western blotting, was positive. Differences in the methods of antigen preparation and of epitopes recognized by individuals may account for different reactivities in the tests. It is concluded that infections of E. cuniculi are common in the tropics and that reactivations of these infections might be a hazard to AIDS patients.

Adult↗