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Biomedical subjects

D H Ellis

Publications and source records attributed to D H Ellis.

At least 37 records · Page 2Linked to original sources
PubMed1993

Complete eradication of Aspergillus fumigatus from the lung in an immunocompromised patient by oral itraconazole.

Itraconazole is a new orally active antifungal agent shown to have in vitro and experimental activity against Aspergillus spp. This case report documents the successful eradication of biopsy-proven invasive pulmonary aspergillosis in a 17 year old boy with acute lymphocytic leukaemia. Cerebral involvement by the fungal infection was suspected clinically but was not biopsy proven. Although the patient subsequently died following bone marrow transplant and Escherichia coli septicaemia there was no evidence of residual Aspergillus at autopsy.

Administration, Oral↗
PubMed1993

Two fatal infections in immunocompromised patients caused by Scedosporium inflatum.

Two fatal infections caused by Scedosporium inflatum in immunocompromised patients are described. One patient developed peritonitis with this fungus 3 mths post renal transplantation. After a stormy course in the intensive care unit he eventually died. The other patient was suffering from non-Hodgkin's lymphoma and showed persistent neutropenia. Progressive deterioration occurred, and disseminated fungal infection was found at post mortem. Both isolates were resistant to all commonly available antifungal agents.

Aged↗
PubMed1992

Fatal disseminated Scedosporium inflatum infection in a neutropenic immunocompromised patient.

Disseminated infection with the fungus Scedosporium inflatum in a neutropenic patient with non-Hodgkins lymphoma presented with the triad of muscle tenderness, papular skin lesions and fever, and progressed rapidly to a fatal outcome. This represents the first reported instance of fatal widely disseminated infection with this organism, and demonstrates that the triad of presenting clinical features, formerly reported to be pathognomic of systemic candidiasis, can no longer be regarded as specific for infection with a particular species of yeast or fungus.

Aged↗
PubMed1992

Clinical features of human infection with Scedosporium inflatum.

We report on 17 Australian cases of human infection or colonization with Scedosporium inflatum. The spectrum of clinical manifestations was similar to that in infection caused by Scedosporium apiospermum. The patients were classified into three groups. Four immunocompetent patients who presented with localized infections of a joint, nail bed, eye, or sphenoidal sinus made up the first group. Our first case, in a boy with posttraumatic septic arthritis, responded to surgical drainage with amphotericin B followed by treatment with itraconazole. The other three cases were cured by surgery alone. The second group consisted of five immunocompromised patients who presented with disseminated infections in a variety of sites. Four of these patients did not respond to antifungal therapy and died. The fifth apparently responded to antifungal drugs after correction of his neutropenia. The third group included eight patients with asymptomatic colonization in the external ear (five cases) or respiratory secretions (three cases). The nine isolates of S. inflatum tested by both disk and agar dilution methods were resistant to antifungal drugs. In our first case, which responded clinically to itraconazole, the MIC of this drug for the fungal isolate was 25 micrograms/mL. Thus S. inflatum can cause a broad spectrum of human infections whose severity and prognosis depend largely on the host's immune status.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Environmental isolation of Cryptococcus neoformans var. gattii from Eucalyptus tereticornis.

As an extension of the previously established association between Cryptococcus neoformans var. gattii and Eucalyptus camaldulensis (River red gum) we have now found a similar relationship between C. neoformans var. gattii and the closely related Eucalyptus tereticornis (Forest red gum). The global distribution of E. tereticornis is similar to that of E. camaldulensis.

Cryptococcus neoformans↗
PubMed1991

Raptor responses to low-level jet aircraft and sonic booms.

We estimated effects of low-level military jet aircraft and mid- to high-altitude sonic booms (actual and simulated) on nesting peregrine falcons (Falco peregrinus) and seven other raptors by observing their responses to test stimuli, determining nesting success for the test year, and evaluating site reoccupancy rates for the year following the tests. Frequent and nearby jet aircraft passes: (1) sometimes noticeably alarmed birds, (2) occasionally caused birds to fly from perches or eyries, (3) most often evoked only minimal responses, and (4) were never associated with reproductive failure. Similarly, responses to real and simulated mid- to high-altitude sonic booms were often minimal and never appeared productivity limiting. Eighteen (95%) of 19 nest sites subjected to low-level jet flights and/or simulated sonic booms in 1980 fledged young during that year. Eighteen (95%) of 19 sites disturbed in 1980 were reoccupied by pairs or lone birds of the same species in 1981. We subjected four pairs of prairie falcons (Falco mexicanus) to low-level aircraft at ad libitum levels during the courtship and incubation phases when adults were most likely to abandon: all four eyries fledged young. From heart rate (HR) data taken via a telemetering egg at another prairie falcon eyrie, we determined that stimulus-induced HR alterations were comparable to rate changes for birds settling to incubate following flight. While encouraging, our findings cannot be taken as conclusive evidence that jet flights and/or sonic booms will have no long-term negative effects for other raptor species or for other areas. In addition, we did not experiment with totally naive wild adults, rotary-winged aircraft, or low-level sonic booms.

Journal Article↗
PubMed1990

Ecology, life cycle, and infectious propagule of Cryptococcus neoformans.

Cryptococcus neoformans is a biotrophic smut-like fungus, and the epidemiology of cryptococcosis can mainly be explained by exposure to an infective aerosolised inoculum. For C neoformans var gattii it is postulated that the principal infectious propagule is the basidiospore and that exposure to Eucalyptus camaldulensis, the host tree, is required to initiate infection in man and animals. C neoformans var gattii may have been exported from Australia by infected seeds of E camaldulensis containing dormant dikaryotic mycelium of the fungus. For C neoformans var neoformans both the basidiospore and desiccated encapsulated yeast cells are postulated to act as infectious propagules, the basidiospores showing a seasonal distribution in association with an as yet unidentified host plant, and the encapsulated yeast cells dispersed from accumulations of dried bird (mainly pigeon) droppings which act as a year-round vector.

Algorithms↗
PubMed1990

Natural habitat of Cryptococcus neoformans var. gattii.

Environmental isolations have established that Cryptococcus neoformans var. gattii appears to have a specific ecological association with Eucalyptus camaldulensis. So far, we have isolated C. neoformans var. gattii on 35 separate occasions, all from samples associated with E. camaldulensis. The global distribution of E. camaldulensis appears to correspond to the epidemiologic distribution of cryptococcosis caused by C. neoformans var. gattii. No other environmental source for the fungus has yet been detected, and no other eucalypt has the distribution pattern corresponding to reported cases caused by this fungus. These findings may provided an explanation for the high incidence of infections caused by C. neoformans var. gattii in Australian aborigines living in the Northern Territory and for its low worldwide incidence in acquired immunodeficiency syndrome patients.

Australia↗
PubMed1990

Burn wound zygomycosis caused by Apophysomyces elegans.

A case of zygomycosis caused by Apophysomyces elegans in a patient having 25% full-thickness burns is described. Amputation of the leg was necessary to control rapid tissue invasion. The fungus was isolated from soil in the burn environment.

Amputation, Surgical↗
PubMed1987

Mycetoma associated with Acremonium falciforme infection.

A patient from Vanuatu with a mycetoma of the foot of 25 years' duration is described. Culture of a biopsy specimen from the foot grew a fungus which was identified as Acremonium falciforme. This agent has not been described previously in association with mycetomas in the Pacific region.

Acremonium↗
PubMed1987

Enzyme-amplified immunoassays.

The sensitivity of enzyme immunoassays may be enhanced by the use of enzyme-amplification. This technique uses the enzyme label in the immunoassay to provide a trigger substance for a secondary system that can generate a large quantity of coloured product. Two examples of enzyme amplifiers are described, using either a substrate cycle with phosphorylated hexose sugars, or a redox cycle involving the coenzyme NAD(+). The redox enzyme-amplifier has a detection limit of less than one attomole for the enzyme label, alkaline phosphatase. The limited dynamic range of enzyme-amplified immunoassays may be overcome by kinetic analysis of the colour development in the enzyme-amplifier, to add at least a further order of magnitude to the range of directly measured analyte concentrations in the immunoassay. This is illustrated in an enzyme-amplified immunoassay for human thyroid stimulating hormone. Amperometric measurement of the enzyme-amplifier provides a method to extend the dynamic range still further and compares favourably with the performance of a gamma counter, a luminometer or a fluorimeter.

Journal Article↗
PubMed1987

Cryptococcus neoformans var. gattii in Australia.

An examination of 45 clinical isolates of Cryptococcus neoformans revealed an unusually high incidence of C. neoformans var. gattii in South Australia (65%) and in the Northern Territory (95%). In assessing all the available data from Australian isolates of C. neoformans, there appeared to be an endemic focus for the incidence of C. neoformans var. gattii in the rural aboriginal population of the Northern Territory.

Australia↗
PubMed1986

Enzyme amplification for immunoassays. Detection limit of one hundredth of an attomole.

A method is described for increasing the response of enzyme immunoassays employing alkaline phosphatase as the label initiating 2 sequential catalytic reactions. First, NADP is dephosphorylated to produce NAD, which catalytically activates a specific redox-cycle involving the enzymes alcohol dehydrogenase and diaphorase. During each turn of the cycle 1 molecule of a tetrazolium salt is reduced to an intensely coloured formazan. The method is capable of detecting as little as 0.01 amol alkaline phosphatase, and when applied to an immunoassay for TSH a sensitivity (zero + 2.5 standard deviations) of 0.0013 mIU/l was obtained.

Alkaline Phosphatase↗
PubMed1985

Maturation and function of the hamster spermatozoon probed with monoclonal antibodies.

To investigate the surface of the mammalian spermatozoon during its maturation in the epididymis, seven monoclonal antibodies were raised in mice against intact spermatozoa (and isolated sperm heads) recovered from the cauda epididymis of the golden hamster. These antibodies, which with one exception were species specific, recognized various membrane components over restricted regions of the sperm head and tail. During epididymal transit the localisation of four antigens bound by these antibodies was considerably altered. In two cases, antigens were first detected on spermatozoa in the distal corpus epididymis where sperm fertilising capacity is initially acquired. A monoclonal antibody which bound to the acrosome and midpiece specifically blocked fertilisation of intact oocytes of the hamster in vitro. Preliminary characterisation of the antigens was undertaken.

Animals↗