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Biomedical subjects

D Harte

Publications and source records attributed to D Harte.

6 recordsLinked to original sources
PubMed2005

Milk amyloid A: correlation with cellular indices of mammary inflammation in cows with normal and raised serum amyloid A.

This study compared concentrations of amyloid A in bovine milk with the cell-based indicators of intramammary inflammation, somatic cell count and California Mastitis Test. Mammary quarter data pertaining to 180 cows were categorised according to concentrations of serum amyloid A in the cow of origin. Ranked correlation, ranked regression and receiver operator characteristics all demonstrated acceptable agreement between milk amyloid A concentrations and cell-based indices. There were some indications of reduction in this agreement, in cows with raised concentrations of serum amyloid A. However, there were also indications that serum amyloid A did not significantly influence milk amyloid A. The results of the current study indicate that milk amyloid A exhibits good correlation with established cell-based indicators of intramammary inflammation.

Animals↗
PubMed2000

Investigation of the prevalence of Legionella species in domestic hot water systems.

AIMS: To investigate the prevalence of Legionella spp. in the hot water systems of a representative sample of Wellington domestic residences with electrically heated hot water systems, and to investigate risk factors (eg water temperature, plumbing materials) for such contamination. METHOD: 100 households with electrically heated hot water systems in the Wellington area were investigated. Samples of hot water from several hot water outlets were collected, and characteristics of the plumbing system were recorded. Water samples and swabs were cultured and further examined by polymerase chain reaction (PCR) and direct fluorescence antibody (DFA) testing to identify Legionella spp. and serogroups. RESULTS: No Legionella spp. were isolated by culture. PCR tested positive for Legionella in specimens from twelve residences. Six of these were also positive by DFA testing. The only environmental factor found to be associated with the presence of Legionella was recent plumbing work on the hot water system. Five of the twelve PCR-positive residences, and four of the six DFA-confirmed residences had hot water delivery temperatures in excess of 60 degrees C. CONCLUSIONS: The results suggest that either Legionellae colonise domestic hot water reticulation systems and/or that the organisms are killed during passage through the hot water tank. Both possibilities may be correct. Further work to characterise the microbial ecology of Legionella-positive hot water distribution systems would be useful, as would the development of improved methods for culturing the organisms from potable water.

Humans↗
PubMed2000

Cumulative incidence of hepatitis C seroconversion in a cohort of seronegative injecting drug users.

AIM: To measure the cumulative incidence of hepatitis C virus seroconversion over a two year period in a group of seronegative injecting drug users. METHODS: The study involved follow-up, in 1996, of a cohort (n=85) of injecting drug users identified as hepatitis C virus seronegative in 1994. Participants were interviewed about risk factors for hepatitis C. A blood sample was also taken for anti-hepatitis C virus antibody and hepatitis C virus RNA testing. RESULTS: Forty-four participants were interviewed and 39 gave blood for testing. Most (80%) were aged 29 years or under and two thirds (n=26) were male. Around half reported borrowing (49%) or lending (57%) needles and syringes since 1994 and both of these behaviours were associated with seroconversion. The majority (88%) also reported sharing other injecting equipment. Nine were anti-hepatitis C virus positive giving a seroconversion rate over two years of 23% (13 per 100 person years). Four out of the nine seropositive specimens tested were also hepatitis C virus RNA positive. CONCLUSIONS: This study demonstrates a high rate of recent hepatitis C virus seroconversion amongst a group of New Zealand injecting drug users. Transmission of hepatitis C virus appears to be unabated by current control measures. These findings confirm the need to develop more effective policy and practices to prevent further spread, not just of hepatitis C, but of other blood-borne viruses in injecting drug user populations.

Adolescent↗
PubMed1994

The Grand Rapids dip revisited.

This analysis addresses an issue that has concerned road safety authorities for some 28 years: the celebrated "Grand Rapids Dip." This, most readers will recognise, is the below-baseline excursion, which occurs in the blood alcohol concentration (BAC) interval of .01%-.04%, of the relative risk curve for accident risk versus blood alcohol, derived from the 1964 Grand Rapids Study data. The present analysis has its starting place in the explanation advanced by Allsop, who noted that the case/control comparisons were biased due to the disproportionate representation of demographic subgroups in different blood alcohol concentration class intervals. Indeed, when relative-risk curves are derived separately for subgroups of differing drinking habits, the resulting separate risk curves all show monotonic increases at all blood alcohol concentration ranges. Such separate relative risk curves are unpopular, and most of the road safety community pays them little heed. Thus, the original concept of the "dip" remains with us. For this reason, we have derived, using a simple but realistic statistical model, a single relative-hazard curve from the Grand Rapids data, one that is free from the distortion introduced by unequal representation of different demographic subgroups in different blood alcohol concentration class intervals. This curve indicates that accident risk increases with increased blood alcohol concentration regardless of self-reported drinking frequency. However more frequent drinkers have less risk at all blood alcohol concentration levels, including zero, than less frequent drinkers at the times and places sampled.

Accidents, Traffic↗