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D C Sutherland

Publications and source records attributed to D C Sutherland.

At least 19 recordsLinked to original sources
PubMed1996

Development of the Drosophila tracheal system occurs by a series of morphologically distinct but genetically coupled branching events.

The tracheal (respiratory) system of Drosophila melanogaster is a branched network of epithelial tubes that ramifies throughout the body and transports oxygen to the tissues. It forms by a series of sequential branching events in each hemisegment from T2 to A8. Here we present a cellular and initial genetic analysis of the branching process. We show that although branching is sequential it is not iterative. The three levels of branching that we distinguish involve different cellular mechanisms of tube formation. Primary branches are multicellular tubes that arise by cell migration and intercalation; secondary branches are unicellular tubes formed by individual tracheal cells; terminal branches are subcellular tubes formed within long cytoplasmic extensions. Each level of branching is accompanied by expression of a different set of enhancer trap markers. These sets of markers are sequentially activated in progressively restricted domains and ultimately individual tracheal cells that are actively forming new branches. A clonal analysis demonstrates that branching fates are not assigned to tracheal cells until after cell division ceases and branching begins. We further show that the breathless FGF receptor, a tracheal gene required for primary branching, is also required to activate expression of markers involved in secondary branching and that the pointed ETS-domain transcription factor is required for secondary branching and also to activate expression of terminal branch markers. The combined morphological, marker expression and genetic data support a model in which successive branching events are mechanistically and genetically distinct but coupled through the action of a tracheal gene regulatory hierarchy.

Animals↗
PubMed1994

Hospital administrators' tolerance of staff needlestick injuries.

OBJECTIVE: To survey hospital administrators regarding their opinions of an acceptable frequency of staff needlestick injury and the frequency that would prompt additional preventive action. DESIGN: A simple anonymous questionnaire sent to 960 administrators with one reminder. Data were collected regarding hospital size and community role, whether human immunodeficiency virus (HIV)-infected patients had ever been treated, presence of an infection control practitioner, estimation of the proportion of staff vaccinated against hepatitis B, and opinions as to the acceptable frequency of needlestick accidents and the accident frequency, requiring additional action. SETTING: 240 public hospitals in New South Wales, Australia. PARTICIPANTS: The executive officers, directors of medical services, directors of nursing, and safety officers of the hospitals surveyed. RESULTS: The response rate was 50%. Administrators' opinions of acceptable accident frequency increased with hospital size and (independently of size) with experience with HIV-infected patients, and with the presence of a full-time infection control practitioner. Accident frequencies judged to require additional preventive action were higher than injury frequencies regarded as acceptable. CONCLUSIONS: The hospital administrators surveyed accept staff needlestick injuries as inevitable, the more so in hospitals that have treated known HIV-infected patients and that have full-time infection control practitioners.

Accidents, Occupational↗
PubMed1994

HIV--Australasian experience. Current status of HIV infection in Australasia.

The HIV/AIDS pandemic continues to evolve in a volatile and heterogeneous fashion and is now best described as a series of different but related epidemics, all posing their own particular problems. The response to the first decade of the epidemic in Australasia has been effective in a number of ways, but much remains to be done. The problems raised by recent cases of transmission of HIV in a health care setting have yet to be resolved. The characteristics of the local epidemic are increasingly divergent from the overseas models used to date, necessitating a flexible and creative approach tailored to the particular characteristics and needs of the local communities.

Australia↗
PubMed1993

A 19F-NMR study of the membrane-binding region of D-lactate dehydrogenase of Escherichia coli.

D-Lactate dehydrogenase (D-LDH) is a membrane-associated respiratory enzyme of Escherichia coli. The protein is composed of 571 amino acid residues with a flavin adenine dinucleotide (FAD) cofactor, has a molecular weight of approximately 65,000, and requires lipids or detergents for full activity. We used NMR spectroscopy to investigate the structure of D-LDH and its interaction with phospholipids. We incorporated 5-fluorotryptophan (5F-Trp) into the native enzyme, which contains five tryptophan residues, and into mutant enzymes, where a sixth tryptophan is substituted into a specific site by oligonucleotide-directed mutagenesis, and studied the 5F-Trp-labeled enzymes using 19F-NMR spectroscopy. In this way, information was obtained about the local environment at each native and substituted tryptophan site. Using a nitroxide spin-labeled fatty acid, which broadens the resonance from any residue within 15 A, we have established that the membrane-binding area of the protein includes the region between Tyr 228 and Phe 369, but is not continuous within this region. This conclusion is strengthened by the results of 19F-NMR spectroscopy of wild-type enzyme labeled with fluorotyrosine or fluorophenylalanine in the presence and absence of a nitroxide spin-labeled fatty acid. These experiments indicate that 9-10 Phe and 3-4 Tyr residues are located near the lipid phase.

DNA Mutational Analysis↗
PubMed1992

Biotypes of Haemophilus parainfluenzae from the respiratory secretions in chronic bronchitis.

A total of 2401 isolates of Haemophilus parainfluenzae was isolated from respiratory secretions of 36 healthy adults and 128 patients with chronic bronchitis over a period of 1 year. The isolates were allocated to eight biotypes, by their production of indole, urease and ornithine decarboxylase. Biotypes I and II constituted most of the isolates of H. parainfluenzae from the oropharynx of controls (75%) and chronic bronchitics (c. 90%). Among the patients, there was no difference in the isolation rate between oropharyngeal swabs and sputum specimens. Biotypes III, IV, VI, VII and VIII were isolated less frequently, as was a new taxon defined here as biotype V which does not produce indole, urease or ornithine decarboxylase. Biotype III was isolated significantly less frequently from cases of chronic bronchitis than from controls, whereas biotype II was isolated somewhat more frequently from the patients, especially during acute episodes.

Adult↗
PubMed1991

HIV and nutrition.

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Acquired Immunodeficiency Syndrome↗
PubMed1991

Lessons from Oregon.

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Acquired Immunodeficiency Syndrome↗
PubMed1991

Wheat dust-associated respiratory disease in a farming community.

Sixty-six volunteers who considered themselves to have wheat dust-related respiratory disease, were reviewed from a farming community. A spectrum of disease was described ranging from a mild allergic rhinitis limited to periods of wheat dust exposure through to perennial asthma in which wheat dust was but one of several precipitating factors. Approximately half of those with asthma had symptoms limited to times of wheat dust exposure. Results of a limited survey of farmers showed patterns of symptoms similar to those in the volunteer group. Most subjects were atopic with elevated IgE levels, and had positive skin prick tests to environmental allergens. All but one of 65 subjects tested had a positive RAST test to wheat dust antigen. It is concluded that wheat dust associated respiratory tract disease is a significant problem in Australian farming communities, that a particular pattern of asthma can be described, and that IgE mediated reactions contribute to this disease pattern.

Adolescent↗
PubMed1990

Bacterial colonisation of the respiratory tract in chronic bronchitis.

One hundred and nine subjects with chronic bronchitis were studied prior to winter and without clinical infection, to determine baseline patterns of bacterial colonisation. Qualitative analysis of cultures of oropharyngeal swabs showed little difference from age matched normal controls (17) except for growth of small numbers of Gram negative coliforms in the chronic bronchitic group. Quantitation of bacteria colonising the oropharynx showed small numbers (mean of 10(5) cfu/ml), with no particular bacteria dominating. Haemophilus influenzae was present in 7.3% of throat swabs from chronic bronchitic patients, but the organism was always less than 10% of the total count. Quantitation of bacteria in sputum showed significantly higher numbers (mean 10(7) cfu/ml). H. influenzae was detected in 25.7% of available specimens, and when present constituted greater than 90% of the total count. Biotyping of H. influenzae isolates demonstrated a separate colonisation of the upper and lower respiratory tracts.

Aged↗
PubMed1990

Evaluation of a selective medium for the isolation and differentiation of Haemophilus influenzae and Haemophilus parainfluenzae from the respiratory tract of chronic bronchitics.

Respiratory tract specimens from chronic bronchitic patients were cultured for Haemophilus species on conventional chocolate agar and a modified sucrose medium in order to determine the accuracy of the new medium in differentiating Haemophilus influenzae from Haemophilus parainfluenzae strains. Haemophilus influenzae biotypes II and III and Haemophilus parainfluenzae biotypes I and II were found to be the predominant strains isolated from the respiratory tract. The modified sucrose medium was found to be a rapid and reliable means of differentiating Haemophilus influenzae from Haemophilus parainfluenzae by sucrose fermentation, on initial isolation.

Bronchitis↗