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Biomedical subjects

N French

Publications and source records attributed to N French.

At least 19 recordsLinked to original sources
PubMed1996

Very preterm birth--a regional study. Part 1: Maternal and obstetric factors.

OBJECTIVE: To ascertain the demographic, pregnancy and obstetric factors associated with the delivery of a liveborn very preterm infant ( < 33 weeks of gestation) and to investigate any differences in these factors between identifiable aetiological groups. DESIGN: Cohort analytical study. SETTING: King Edward Memorial Hospital for Women (KEMH), Western Australia. MAIN VARIABLES EXAMINED: Maternal demographic and obstetric history, primary complication associated with delivery, obstetric management and mode of delivery. RESULTS: Six hundred and eight women who were delivered of 693 liveborn very preterm infants in Western Australia between 1.1.90 and 31.12.91, representing 1.22% of all women who were delivered of a liveborn infant in those years. Singleton pregnancy occurred in 517 (85%) and 541 (89%) were delivered in KEMH. Mean maternal age was 28 years with an excess of mothers less than 20 years of age and older than 34 years compared with the statewide perinatal data. Pre-eclampsia (n = 128, 21.1%), preterm prelabour rupture of membranes (n = 148, 24.3%), idiopathic preterm labour (n = 195, 30.4%) and antepartum haemorrhage (n = 111, 18.3%) were associated with 94.1% of deliveries. These proportions varied with plurality and period of gestation. Demographic details, use of antenatal steroids, exposure to labour and caesarean section delivery differed between mothers depending on the primary complication. Overall 322 (53.0%) received antenatal steroids and 297 (48.8%) were delivered by caesarean section. Factors associated with decreased use of steroids were gestational age of less than 27 weeks (odds ratio (OR) 0.54; 95% CI 0.36-0.83), preterm prelabour rupture of the membranes (OR 0.48; 95% CI 0.29-0.78) and idiopathic preterm labour (OR 0.56; 95% CI 0.35-0.91). Factors associated with increased use of steroids were multiple pregnancy (OR 1.70; 95% CI 1.02-2.81) and pre-eclampsia (OR 1.87; 95% CI 1.09-3.19). CONCLUSIONS: These very preterm deliveries account for only a small proportion of all deliveries. There are differences in the mother's demographic history, obstetric management and delivery depending on the primary aetiological factor.

Adult↗
PubMed1996

Very preterm birth--a regional study. Part 2: The very preterm infant.

OBJECTIVE: To ascertain the growth characteristics, delivery room management and hospital mortality of very preterm liveborn infants (< 33 weeks of gestation) and to identify differences between infants associated with the aetiological factor related to their very preterm delivery. DESIGN: Cohort analytical study. SETTING: King Edward Memorial Hospital for Women, Western Australia. MAIN VARIABLES EXAMINED: Gestational age, birthweight, birthweight ratio, condition at birth and mortality. RESULTS: Six hundred and ninety-three liveborn very preterm infants were born to 608 mothers between 1.1.90 and 31.12.91. This was 1.37% of all liveborns in Western Australia. Three hundred and eighty-five (55.6%) were male. Growth characteristics (birthweight, birthweight ratio and proportion small for gestational age) differed between infants depending on the primary obstetric complication associated with the very preterm delivery. Overall 217 (31%) infants were small for gestational age, 34(4.9%) had a congenital anomaly, and 102 (14.7%) died. Corrected mortality, excluding major fatal congenital anomaly, was 86 (12.7%). The majority of infants died on the first day (n = 59 (57.8%)). The only factors associated with an increased or decreased mortality were decreasing gestation (adjusted odds ratio (AOR) 1.7, 95% CI 1.50-1.93), decreasing birthweight ratio (small for gestational age) (AOR 1.3, 95% CI 1.08-1.53), antepartum haemorrhage as primary complication (AOR 3.1, 95% CI 1.25-7.69) and any antenatal steroids (AOR 0.26, 95% CI 0.14-0.51). In comparison with other studies, survival in the extremely preterm group, defined as a gestational age of less than 28 weeks, is improving. CONCLUSIONS: Very preterm infants account for a large proportion of perinatal mortality. Further studies are required to explore the differences between infants on the basis of the primary obstetric complication and to ensure that increased survival is not associated with an increase in disabilities.

Abortion, Induced↗
PubMed1995

Idazoxan-induced reductions in cortical glucose use are accompanied by an increase in noradrenaline release: complementary [14C]2-deoxyglucose and microdialysis studies.

The autoradiographic [14C]2-deoxyglucose procedure was used to map function-related alterations in local cerebral glucose use following acute administration of the alpha 2-adrenoceptor antagonist, idazoxan (0.3-3 mg kg-1 s.c.). The most prominent feature of the results obtained was the significant reduction in glucose use in certain locus coeruleus projection areas. Thus, in various cortical, hippocampal and thalamic regions, as well as structures involved in auditory and visual function, idazoxan administration was associated with a 13-20% decrease in glucose use. In a complementary microdialysis study, the effect of idazoxan on extracellular noradrenaline levels in the frontal cortex of rats, manipulated in the same fashion as during the [14C]2-deoxyglucose procedure (i.e. following the application of surgery and partial restraint), was examined. Both surgery and restraint were associated with a modest but significant increase in basal noradrenaline release (+31% and +26%, respectively). Subsequent administration of idazoxan (3 mg kg-1 s.c.) evoked a further increase in noradrenaline release, the magnitude of which was the same as that observed following its administration to freely-moving rats (+113%). These combined data suggest that idazoxan-induced reductions in cerebral glucose use, at least in the frontal cortex, may occur as a consequence of the increase in noradrenaline release. In addition, it appears that surgery and partial restraint do not alter alpha 2-adrenoceptor tone in the frontal cortex.

Adrenergic alpha-Antagonists↗
PubMed1995

Alpha 2-adrenoceptors and I2 sites in the mammalian central nervous system.

The presence of alpha 2-adrenoceptors and I2 sites in the central nervous system is well established. This review provides a complete summary of this literature, commencing with the first description of alpha 2-adrenoceptors and I2 sites in the brain and covering in detail their subclassification, distribution, and function. Furthermore, it highlights some important differences between central alpha 2-adrenoceptors and I2 sites.

Animals↗
PubMed1994

Blowfly strike in England and Wales: the relationship between prevalence and farm and management factors.

In order to develop and evaluate control strategies for blowfly strike, a greater understanding of the epidemiology is essential. A postal survey of sheep farmers yielded information about ten farm and management factors and their relationship to blowfly strike prevalence. The risk of a farm reporting at least one case of blowfly strike increased as flock size and stocking density increased (adjusted odds ratio of 1.13 for an increase in flock size of 100 sheep and 1.38 for an increase in stocking density of ten sheep per hectare). As farm altitude increased, the risk of blowfly strike decreased (adjusted odds ratio 0.67 for an increase in farm altitude of 100 m). The risk of high strike prevalence (more than 2% of sheep struck) decreased as both farm altitude and flock size increased. High strike prevalence was also associated with on-farm sheep carcase disposal (odds ratio 1.35). Farmers in the south-west of England were more likely to report at least one case of blowfly strike and high strike prevalence compared to all other regions.

Agriculture↗
PubMed1992

Development of an attractive target for the sheep blowfly Lucilia sericata.

Coloured, odour-baited, sticky targets, designed to catch the sheep blowfly Lucilia sericata Meigen are described and the results of field trials are presented. The number of L. sericata caught by the targets was positively related to target surface area and was dependent on target colour. The performance of the coloured targets is described by a model in which catch is related negatively to reflectivity in the 300-450 nm (ultra-violet/blue) band of the spectrum and positively to the reflectivity in the 450-580 nm (blue-green-yellow) band. Of the Lucilia blowflies caught by the targets, 13-16% were L.sericata and 72-75% of the L.sericata were female. The number of L.sericata caught appeared to be positively related to the availability of sheep over a relatively localized area and showed a marked decline following insecticidal dipping of sheep. The further development of targets and the implications of the results for L.sericata control are discussed.

Animals↗
PubMed1990

Effects of feeding frequency and exogenous somatotropin on lipolysis, hormone profiles, and milk production in dairy cows.

Effects of feeding frequency and exogenous bovine somatotropin on lactational performance and hormone profiles were examined with 12 multiparous Holstein cows. At 45 d postpartum, cows were assigned to one of two feeding systems. Concentrates were offered in two equal portions at 0800 and 1600 h or in 12 equal portions at 2-h intervals. Chopped alfalfa hay (2.6 kg/d) and barley silage (ad libitum) were fed at 0900 and 1500 h. At 136 d postpartum, cows within each feeding frequency were assigned in a single crossover design to injection of 30 mg of bST/d or solubilization vehicle. Feeding frequency did not influence any of the parameters measured nor did bST interact with feeding frequency. Somatotropin injection increased daily milk yield of cows by 4.4 kg and concentrations of fat and lactose in milk. Protein concentration and fatty acid composition of milk were not influenced by bST injection. Average plasma somatotropin concentrations were elevated threefold, peak concentrations were increased sevenfold, and concentrations at 48 h postinjection were 1.5 times control values. Plasma insulin concentrations were decreased by bST treatment. Results indicate that responses to short-term bST injection are not influenced by feeding frequency.

Animals↗
PubMed1990

Effects of feeding frequency on ruminal parameters, plasma insulin, milk yield, and milk composition in Holstein cows.

Two experiments were conducted to determine the effects of frequency of feeding on ruminal fermentation, blood parameters, milk yield, and milk composition in cows fed a 60% pelleted concentrate and 40% chopped alfalfa hay (DM basis) diet. In Experiment 1, four ruminally cannulated cows were fed concentrates in 12 equal portions at 2-h intervals or in two equal portions at 0500 and 1500 h in a crossover design. In Experiment 2, treatments were as in Experiment 1 plus an additional treatment consisting of a total mixed diet fed at 2-h intervals in a 3 x 3 Latin square design. All treatment periods were 2 wk. In Experiment 1, increased frequency of concentrate feeding tended to result in elevated ruminal pH and increased acetate to propionate ratio. Plasma insulin concentration tended to be higher (1.54 vs. 1.04 ng/ml) and milk fat percentage increased from 2.21 to 2.60% for 2 and 12 times daily feeding, respectively. In Experiment 2, frequency of feeding concentrate or total mixed diet did not affect ruminal and blood parameters or milk yield. In both experiments, milk protein and lactose concentrations were not influenced by feeding frequency. Results suggest that where intake is kept constant, increased feeding frequency will not influence milk yield but could result in elevated milk fat percent in animals fed fat-depressing diets.

Animals↗
PubMed1977

Control of headfly on sheep.

Headfly caused irritation to sheep in Northumberland from late June of each year 1973 to 1975. Numbers of headflies caught in sweep nets declined sharply from early August 1973 and 1975 but remained fairly high in 1974 until mid September. Attacks on sheep followed a similar pattern. The effectiveness of a number of fly repellent applications was examined. Headcaps gave good and sometimes complete protection.

Animals↗