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Biomedical subjects

S M Eades

Publications and source records attributed to S M Eades.

17 recordsLinked to original sources
PubMed1980

Infection with Absidia corymbifera in bank voles (Clethrionomys glariolus).

Bank voles, Clethrionomys glariolus, kept under laboratory conditions were highly susceptible to both naturally-acquired and experimental infection with the phycomycete Absidia corymbifera. The infection was manifested as an acute lethal disease characterized by fungal invasion of the kidneys, central nervous system and, less frequently, other tissues. Natural infection was probably acquired via the respiratory route.

Acute Disease↗
PubMed1978

Observations on the localization of Absidia corymbifera in vivo.

The role of spore distribution and the presence of tissue-specific fungal growth stimulants and inhibitors in determining the in vivo localization of Absidia corymbifera were examined in experimentally infected mice. Intravenous inoculation resulted in generalized distribution of spores, with the highest concentrations accumulating in the liver and spleen. Active lesions containing developing mycelium were confined to the brain, kidneys and occasionally the myocardium. Fungal growth stimulating activity was present in all tissue examined, the liver and spleen being the most active. However at concentrations approaching those of whole tissues, the stimulatory activity of liver and spleen extracts drastically declined whereas that of brain and kidney preparations continued to increase. These effects, in conjunction with local variations in immune processes, were probably responsible for determining the distribution of A. corymbifera mycelial development in vivo.

Animals↗
PubMed1977

Experimental mucormycosis in congenitally athymic (nude) mice.

Athymic nude (nu/nu) mice and their phenotypically normal (nu/+) littermates displayed a similar susceptibility to acute lethal infection with Absidia corymbifera. Although the clinical manifestations of acute infection were also similar in both groups, the nude mice tended to develop more extensive lesions and were less effective in eliminating viable A. corymbifera spores than their heterozygous littermates. The results suggested that thymus-dependent processes did not play an essential role in primary resistance to mucormycosis.

Animals↗
PubMed1977

Cerebral mucormycosis following experimental inoculation with Mortierella wolfii.

A strain of Mortierella wolfii isolated from a case of bovine mycotic abortion in the United Kingdom did not produce disease in mice when inoculated by the intraperitoneal, intramuscular, intravenous or subcutaneous routes. When injected by the intracerebral route, it induced a chronic granulomatous infection of the brain resulting in hydrocephalus and eventually death.

Animals↗
PubMed1977

Examination of the effect of age and acquired immunity on the susceptibility of mice to infection with Aspergillus fumigatus.

Adult CBA mice showed considerably greater resistance to experimental infection with Aspergillus fumigatus than young animals of the same strain (P less than 0.01). Furthermore, in contrast with the young mice, the susceptibility of the adults was only moderately increased by treatment with cortico-steroids. On the other hand, immunosuppressive treatments producing severe depression of lymphocyte function greatly increased susceptibility to lethal infection and promoted fungal growth in a wide range of tissues. These observations suggested a role for specific acquired immunity in the relatively high resistance to experimental aspergillosis shown by older mice.

Age Factors↗
PubMed1976

Experimental phycomycosis in mice; examination of the role of acquired immunity in resistance to Absidia ramosa.

Attempts were made to stimulate acquired immunity to experimental Absidia ramosa infection in mice. Unprotected animals inoculated with large doses of A. ramosa spores frequently developed acute phycomycosis of the central nervous system. Mice previously exposed to sub-lethal doses of spores showed a high resistance to subsequent challenge with A. ramosa. No consistent increase in resistance was observed in mice vaccinated with killed A. ramosa spores, hyphal walls, intracellular mycelial antigens or various combinations of these, with Freund's incomplete adjuvant. Antibodies to soluble mycelial antigens were inconsistently present in the sera of mice vaccinated with sub-lethal doses of viable spores. They were generally present in the sera of animals vaccinated with mycelial extracts of hyphal walls but not killed spores. Delayed hypersensitivity reactions to A. ramosa mycelial antigens could usually be elicited by intradermal tests in mice exposed to viable spores but irregularly in those vaccinated with non-viable preparations. Positive reactions were also frequently given by older mice not deliberately exposed to A. ramosa. Although mice previously exposed to viable A. ramosa spores were highly resistant to intravenous or intracerebral challenge with this fungus, they were more likely to develop persistent local granulomata on subcutaneous injection of spores than were unvaccinated animals.

Animals↗
PubMed1976

The relative susceptibility of New Zealand black and CBA mice to infection with opportunistic fungal pathogens.

The susceptibility of ageing New Zealand Black (NZB) mice to infection with a number of opportunistic fungi and yeasts wsd compared with that of similarly aged mice of the CBA strain. The NZB mice showed a greater susceptibility to lethal infection with Aspergillus fumigatus, Candida albicans and Cryptococcus neoformans than did those of the CBA strain. Both mouse strains showed similar susceptibility to lethal infection by Allescheria boydii, Absidia corymbifera, Mucor pusillus and Rhizopus oryzae. The clinical and histopathological characteristics of the infections produced by Allesch boydii, Asp. fumigatus, Abs. corymbifera, M. pusillus and R. oryzae were similar for both mouse strains. In contrast C. albicans and Crypto. neoformans produced much more severe infections in NZB mice than in CBA mice. These results suggested that T-lymphocyte dependent immune processes played a major role in resistance to C. albicans and Crypto. neoformans but not to Abs. corymbifera, Allesch. boydii, Asp. fumigatus, M. pusillus or R. oryzae.

Animals↗
PubMed1975

Factors determining the susceptibility of mice to experimental phycomycosis.

Various factors influencing the susceptibility of C3H mice to lethal infection by the phycomycete Absidia ramosa were examined. Mice 19-21 days old were exposed to graded doses of A. ramosa spores by various routes. After intravenous inoculation with doses in excess of 10(3) viable units, a variable proportion of mice developed lethal phycomycosis of the central nervous system within 2-8 days. The proportion of mice affected was related to the inoculum size, doses of 5 X 10(7) spores producing lethal infection in 90-100% of the mice. The disease was characterised by signs of involvement of the central nervous system appearing 8-12 h before death. At necropsy, fungal hyphae, frequently surrounded by infiltrations of mononuclear cells, could be demonstrated in the brain. Lesions were also often present in the kidneys; in other organs they were rare, but the presence of viable fungal spores could be detected by cultural procedures. Subcutaneous inoculation of A. ramosa spores did not produce lethal infection but intraperitoneal inoculation occasionally did so. Direct intracerebral inoculation invariably produced lethal infection even with very small doses of spores. The clinical and histopathological features of the disease were almost identical with those resulting from intravenous inoculation. Pre-inoculation treatment with azathioprine, cyclophosphamide and antithymocyte serum did not increase susceptibility. Susceptibility was increased by injections of zymosan, aggregared gamma-globulin, cortisone acetate and Fe(II) salts and by reticuloendothelial blockade. These treatments increased the proportion of mice developing lethal phycomycosis of the central nervous system, and in the case of cortisone acetate, also promoted disseminated infection. It was concluded that the natural resistance of mice to A. ramosa infection was probably dependent upon the activity of phagocytic cells, possibly acting in conjunction with complement and other non-specific serum factors.

Age Factors↗
PubMed1975

Metastatic subcutaneous zygomycosis following intravenous and intracerebral inoculation of Absidia corymbifera spores.

A subcutaneous granuloma developed in a C3H mouse ca. 5 months after sequential intravenous and intracerebral inoculation of Absidia corymbifera spores. A. corymbifera was demonstrated microscopically and culturally in the lesion. Infection is believed to have been secondary to fungal infection of the kidney. The histopathological features of the lesion are described.

Animals↗
PubMed1968

Perforation of the bowel in the newborn as a complication of exchange transfusion.

Spontaneous perforation of the bowel without evidence of intestinal obstruction is reported in six infants who had exchange transfusions for rhesus incompatibility, and in a seventh who had prolonged intravenous fluids via the umbilical vein. The pathological findings resemble those found in acute necrotizing enterocolitis in adults, which is known to be associated with arterial hypotension. The cause in these infants may also be due to a period of hypotension during the transfusion, and hypoxia and superimposed infection may also play an important part.

Enterocolitis, Pseudomembranous↗
PubMedDate not supplied

Observations on the experimental pathogenicity and toxigenicity of Mortierella wolfii strains of bovine origin.

Four strains of Mortierella wolfii isolated from cattle in Britain were compared in pathogenicity and toxigenicity with a strain isolated from a cow with the mycotic abortion-pneumonia syndrome in New Zealand. All strains produced acute lethal infection in rabbits after intravenous inoculation of mycelial suspensions and all produced subacute mycotic encephalitis in mice after intracerebral injection. They also produced an acid-stable, heat- and trypsin-labile toxin in vitro. The action of the toxin was exerted mainly on the kidneys in rabbits and mice and produced effects distinct from those resulting from infection with M. wolfii.

Abortion, Veterinary↗