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Biomedical subjects

N E Davis

Publications and source records attributed to N E Davis.

14 recordsLinked to original sources
PubMed2006

A survey of waterfowl for echinostomes and schistosomes from Lake Wanaka and the Waitaki River watershed, New Zealand.

Waterfowl from Lake Wanaka and the Waitaki Lakes watershed of New Zealand's South Island were surveyed to find natural hosts with adult echinostomes and schistosomes to provide sufficient numbers of eggs for laboratory studies. The Canada goose (Branta canadensis) was found to host an echinostome determined to be a New Zealand strain of Echinostoma revolutum. The New Zealand scaup (Aythya novaeseelandia) concurrently hosts three species of echinostomes (E. revolutum, Echinoparyphium cinctum and E. recurvatum) plus two species of avian schistosomes (Trichobilharzia sp. and Dendritobilharzia pulverulenta). In the Canada goose and the New Zealand scaup, adult gravid echinostomes predominated over juveniles. In other waterfowl surveyed, very few echinostomes were found, with juveniles predominating.

Animals↗
PubMed2006

Identification of an avian schistosome recovered from Aythya novaeseelandia and infectivity of its miracidia to Lymnaea tomentosa snails.

A partial life cycle involving miracidia hatched from the eggs of Trichobilharzia sp. recovered from New Zealand scaup (Aythya novaeseelandia) to the release of furcocercariae by laboratory snails (Lymnaea tomentosa) was accomplished. Challenges with five and ten miracidia per snail were lethal. Challenge with three miracidia resulted in development to the daughter sporocyst stage and death in five, development to furcocercarial stage and death in one, and shedding of furcocercariae in one of seven snails. Observed lethality of schistosome miracidia to L. tomentosa may explain the low infection prevalence observed in the wild. Future work should plan challenge exposures of three or fewer miracidia to ensure snail survival and successful recovery of furcocercariae. The Trichobilharzia sp. found in the New Zealand scaup does not key morphologically to the literature. It may be a new species and further work is needed.

Animals↗
PubMed2005

Endemic echinostome infections of candidate hosts.

Wild Lymnaea tomentosa snails, recovered from Lake Wanaka, New Zealand, were established in the laboratory. Wild snails, naturally infected with echinostomes, provided metacercariae for infection of laboratory maintained snails. Metacercarial cysts from wild and laboratory snails were then used to attempt infection of definitive host candidates. Laboratory snails provided convenient packaging of known numbers of cysts. Metacercariae excysted in the small intestines of ducklings to mature in 6 days. Worms were expelled as they became gravid. Attempts to establish infections in experimental hosts other than ducklings were not successful. No worms were recovered from mice, white rats, guinea pigs, hamsters or immunosuppressed white rats.

Animals↗
PubMed2005

Storage and incubation of Echinostoma revolutum eggs recovered from wild Branta canadensis, and their infectivity to Lymnaea tomentosa snails.

Echinostoma revolutum eggs recovered from naturally infected wild Canada geese (Branta canadensis) were cold stored (4-6 degrees C) for up to 72 weeks. Successful hatching followed incubation for from 6 to 8 days at an optimum temperature of between 25 and 30 degrees C. A partial life cycle from adult worm to metacercarial encystment in Lymnaea tomentosa snails was completed in the laboratory. Snails were infected both by free miracidia and by ingestment of unhatched embryonated eggs. Infection was equally successful in environmental temperature ranges from 10 to 25 degrees C, and at challenge levels of 2, 5 or 10 embryonated eggs per snail. Exposure to 10 eggs was lethal. Ingestion by snails of embryonated eggs with successful infection at 10 degrees C suggests that embryonated eggs may be used to infect wild snails when the environmental water temperature has reached 10 degrees C.

Animals↗
PubMed1998

Population dynamics of and larval trematode interactions with Lymnaea tomentosa and the potential for biological control of schistosome dermatitis in Bremner Bay, Lake Wanaka, New Zealand.

Lymnaea tomentosa, the intermediate host of a schistosome which causes schistosome dermatitis in Lake Wanaka, was found to depths of 16 m. The snail recruits in January, lives for up to 21 months, is associated with all water plant species and is found in areas devoid of macroscopic plants. It is host to several trematode species. Avian schistosome infections appear in the spring when echinostome prevalence is low, and a decrease in schistosome prevalence may be correlated with an increase in echinostome prevalence during the summer. A multiple-kind lottery model analysis of parasite species richness implies that interspecific interactions may be occurring in the host snail during the months of December and January.

Animals↗
PubMed1984

Developmentally disabled infants can be hard to trace.

The purpose of this study was to determine how well the existing medical care system in a large geographic region communicates about and keeps track of the developmental problems of infants receiving tertiary inpatient care. Two hundred thirty-seven infants hospitalized in the first months of life were tracked, using a postal questionnaire at a mean age of 20 months. A discharge summary was present in 98 percent of charts, and a follow-up physician was identified in 95%. Questionnaires were returned by 116 physicians about 182 infants (77%). Seventy-one physicians had received a discharge summary. Current developmental information was obtained for 111 infants: 44 normal, 52 with known disabilities, and 15 with developmental delays. One hundred twenty-six infants could not be located at the time of the study. We conclude that many infants likely to have major disabilities are hard to track using simple retrospective techniques.

Continuity of Patient Care↗
PubMed1974

The hyperthermic effect of intracerebroventricular cholera enterotoxin in the unanaesthetized cat.

1. Cholera enterotoxin was used to evaluate a possible role of endogenous cyclic AMP in production of hyperthermia. Injection of purified toxin (0.10-1.0 mug in 0.10 ml.) into the lateral cerebral ventricle of unanaesthetized cats caused dose-related hyperthermic responses. Heating the toxin for 40 min at 90 degrees C abolished its hyperthermic activity.2. Intraventricular administration of dibutyryl cyclic AMP (250-1000 mug) also caused hyperthermia which, however, was preceded by transient periods of hypothermia and/or excitation in about half of the tests.3. Paracetamol, indomethacin and sodium salicylate inhibited hyperthermic responses to cholera enterotoxin. Paracetamol and indomethacin also inhibited hyperthermia induced by dibutyryl cyclic AMP (sodium salicylate was not tested).4. It is likely that the hyperthermic effect of cholera enterotoxin in the cat is mediated via endogenous cyclic AMP and that the antipyretics inhibit this effect by an action subsequent to the increase in cyclic AMP.5. It is unlikely that prostaglandin-induced hyperthermia in the cat is mediated via cyclic AMP since these antipyretics do not inhibit this response to prostaglandin E(1).

Acetaminophen↗
PubMed1970

Paper chromatographic techniques for the determination of cephalothin and desacetylcephalothin in body fluids.

Paper chromatographic procedures may be used to detect cephalothin and its metabolite desacetylcephalothin in urine, plasma, synovial fluid, and cerebrospinal fluid. Protein-bound antibiotics are released from plasma, cerebrospinal fluid, and synovial fluid by dilution with an equal volume of dimethylformamide. Data are presented on the sample preparation, paper chromatographic system, and other specific techniques.

Bacillus subtilis↗
PubMedDate not supplied

Recurring digital fibrous tumor of childhood: case report with long-term follow-up and review of the literature.

A case report and literature review of recurring digital fibrous tumors of childhood are presented. Of 92 reported cases, 78 patients were treated surgically. Tumor excision ultimately was curative in 85%, with 64% having recurrences and 10% needing amputation. Our patient, the first with follow-up of greater than 10 years, had extensive tumors of the hands and feet and eventually required partial amputation of many digits. At 19 1/2 years of age, no recurrences were noted. Recurring digital fibrous tumors of childhood should be treated with early surgical excision, with amputation reserved for cases of severe and progressive lesions.

Amputation, Surgical↗