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Biomedical subjects

M E O'Neill

Publications and source records attributed to M E O'Neill.

At least 19 recordsLinked to original sources
PubMed2006

Biomonitoring for assessment of organic dust-induced lung inflammation.

Inhalation exposure to particulate matter containing endotoxin (or lipopolysaccharide (LPS)) occurs in a variety of occupations. Nasal lavage and induced sputum have been used to evaluate lung inflammation resulting from such exposures. Whole blood assay (WBA) measures cytokine production of leukocytes after ex vivo stimulation with LPS. The present study examined the effectiveness of WBA for evaluating inflammatory responses and susceptibility. C3HeB/FEJ mice were tolerised by LPS injection or sham tolerised with saline. Animals then inhaled either swine barn dust extract containing endotoxin or saline. Bronchoalveolar lavage (BAL) fluid was assayed for leukocyte counts and pro-inflammatory cytokines (interleukin-6, tumour necrosis factor-alpha). Whole blood was stimulated with 10 or 100 ng.mL(-1) of LPS, incubated for 5 or 18 h and assayed for cytokines. Barn dust-exposed groups revealed significantly higher total cells, neutrophils and cytokines in BAL compared with saline-exposed groups. Animals tolerised to LPS and exposed to barn dust demonstrated lower cellular and cytokine BAL responses. Similarly, WBA yielded significantly elevated cytokines with barn dust exposure and reduced responses with tolerisation. This study demonstrates the efficacy of whole blood assay as a biomarker of inhalation exposure to inflammatory agents and its use for assessing susceptibility to organic dust-induced lung inflammation.

Animal Husbandry↗
PubMed2001

A European carotenoid database to assess carotenoid intakes and its use in a five-country comparative study.

A food frequency questionnaire (FFQ) and carotenoid database with information on alpha- and beta-carotene, lutein, lycopene and beta-cryptoxanthin was prepared and used to compare the carotenoid intakes in five European countries: UK, Republic of Ireland, Spain, France and The Netherlands. Eighty, age- (25-45 years) and sex-matched volunteers were recruited in each of the five countries. A FFQ and carotenoid database was prepared of the most commonly consumed carotenoid rich foods in the participating countries and the information was used to calculate frequency and intake of carotenoid-rich foods. The median total carotenoid intake based on the sum of the five carotenoids, was significantly higher (P < 0.05) in France (16.1 mg/day) and lower in Spain (9.5 mg/day,) than the other countries, where the average intake was approximately 14 mg/day. Comparison of dietary source of carotenoids showed that carrots were the major source of beta-carotene in all countries except Spain where spinach was most important. Likewise, carrots were also the main source of alpha-carotene. Tomato or tomato products, were the major source of lycopene. Lutein was mainly obtained from peas in Republic of Ireland and the UK, however, spinach was found to be the major source in other countries. In all countries, beta-cryptoxanthin was primarily obtained from citrus fruit. Comparing the data with that from specific European country studies suggests that the FFQ and carotenoid database described in the present paper can be used for comparative dietary intake studies within Europe. The results show that within Europe there are differences in the specific intake of some carotenoids which are related to different foods consumed by people in different countries.

Adult↗
PubMed2001

Endotoxin responsiveness and subchronic grain dust-induced airway disease.

Endotoxin is one of the principal components of grain dust that causes acute reversible airflow obstruction and airway inflammation. To determine whether endotoxin responsiveness influences the development of chronic grain dust-induced airway disease, physiological and airway inflammation remodeling parameters were evaluated after an 8-wk exposure to corn dust extract (CDE) and again after a 4-wk recovery period in a strain of mice sensitive to (C3H/HeBFeJ) and one resistant to (C3H/HeJ) endotoxin. After the CDE exposure, both strains of mice had equal airway hyperreactivity to a methacholine challenge; however, airway hyperreactivity persisted only in the C3H/HeBFeJ mice after the recovery period. Only the C3H/HeBFeJ mice showed significant inflammation of the lower airway after the 8-wk exposure to CDE. After the recovery period, this inflammatory response completely resolved. Lung stereological measurements indicate that an 8-wk exposure to CDE resulted in persistent expansion of the airway submucosal cross-sectional area only in the C3H/HeBFeJ mice. Collagen type III and an influx of cells into the subepithelial area participated in the expansion of the submucosa. Our findings demonstrate that subchronic inhalation of grain dust extract results in the development of chronic airway disease only in mice sensitive to endotoxin but not in mice that are genetically hyporesponsive to endotoxin, suggesting that endotoxin is important in the development of chronic airway disease.

Actins↗
PubMed2000

Influence of increased fruit and vegetable intake on plasma and lipoprotein carotenoids and LDL oxidation in smokers and nonsmokers.

BACKGROUND: Epidemiological studies suggest a cardioprotective role for carotenoid-rich foods. Smokers have a high risk of cardiovascular disease and low dietary intake and plasma concentrations of carotenoids. The aim of this study was to determine the carotenoid response of smokers and nonsmokers to increased intake of 300-400 g of vegetables and its effect on LDL oxidation. METHODS: After a depletion period of 8 days, 34 healthy females (18 nonsmokers, 16 smokers) were supplemented with beta-carotene- and lutein-rich (green) and lycopene-rich (red) vegetable foods, each for 7 days. RESULTS: Baseline concentrations (mean +/- SD) of plasma beta-carotene (0.203+/-0.28 micromol/L vs. 0.412+/-0.34 micromol/L; P <0.005) and lutein (0.180 +/-0.10 vs. 0.242+/-0.11 micromol/L; P<0.05) but not lycopene (0.296+/-0.10 vs. 0.319+/-0.33 micromol/L) were significantly lower in smokers compared with nonsmokers. After supplementation, the change (supplementation minus depletion) in plasma beta-carotene (0.152+/- 0.43 vs. 0.363+/-0.29 micromol/L in smokers vs. nonsmokers; P = 0.002) and LDL lutein (0.015+/-0.03 vs. 0.029+/-0.03 micromol/mmol cholesterol; P = 0.01) was significantly lower in smokers than nonsmokers. Green-vegetable supplementation had no effect on the resistance of LDL to oxidation (lag-phase) in either group. After red-vegetable supplementation, plasma and LDL lycopene concentrations were increased in both groups, but only nonsmokers showed a significant increase in the lag-phase (44.9+/-9.5 min at baseline, 41.4+/-6.5 min after depletion, and 49.0+/-8.9 min after supplementation; P<0.01) compared with depletion. CONCLUSIONS: In this short-term intervention study, a dietary intake of >40 mg/day of lycopene by a group of nonsmoking individuals significantly reduced the susceptibility of LDL to oxidation, whereas an equivalent increase in lycopene by a group of smokers showed no such effect.

Adult↗
PubMed1998

Epidemiology of congenital cytomegalovirus infection: maternal risk factors and molecular analysis of cytomegalovirus strains.

To determine factors that influence the occurrence of congenital cytomegalovirus (CMV) infection, the authors surveyed prospectively 8,254 infants born in eastern Iowa between October 1989 and June 1994. The authors conducted a case-control study to identify maternal risk factors, matching each CMV-infected infant with three uninfected infants according to hospital and date of birth. CMV strains were compared by using the polymerase chain reaction (PCR) to identify common sources of infection. Of the 7,229 infants cultured successfully for CMV, 35 (0.48%) were congenitally infected. Mothers of CMV-infected infants were more likely to be single (odds ratio (OR) = 3.05, p = 0.016), to work in sales (OR = 4.93, p = 0.008), or to be students (OR = 5.01, p = 0.017). Conversely, women who worked in health-care professions were less likely to have a congenitally infected infant (OR = 0.14, p = 0.049). PCR analysis indicated 27 distinct strains of CMV, but two groups of infants (two infants per group) excreted strains with indistinguishable molecular patterns. One of these pairs of infants had older siblings who attended the same child-care center during their mothers' pregnancies. The authors concluded that demographic and occupational factors influenced the risk of giving birth to an infant with congenital CMV infection. Many distinct CMV strains were identified, suggesting that major point source outbreaks had not occurred. Nonetheless, point source acquisition of CMV from child-care environments did account for some cases of congenital CMV infection in eastern Iowa.

Adult↗
PubMed1998

Intestinal absorption of beta-carotene, lycopene and lutein in men and women following a standard meal: response curves in the triacylglycerol-rich lipoprotein fraction.

A high intake of fruit and vegetables is believed to be protective against heart disease and cancer. beta-Carotene has been closely examined for evidence of these protective properties but evidence is still conflicting and there are many other carotenoids in plant foods which deserve attention. This paper reports studies on the concentrations of lutein and lycopene in the triacylglycerol-rich lipoprotein (TRL) fraction of plasma in comparison with beta-carotene following a large dose of the respective carotenoids fed with a standard meal after an overnight fast. beta-Carotene (40 mg) was given to twelve volunteers (six men and six women) and six of the same volunteers (three men and three women) also received 31.2 mg lutein or 38 mg lycopene. Plasma was collected at hourly intervals for 8 h and the TRL fraction was separated and subsequently analysed for the respective carotenoids and retinyl palmitate in the case of beta-carotene. Intestinal uptake of the three carotenoids was estimated using the 'area under the curve' method and apparent absorption was calculated from these results. The response curves in the TRL fraction for beta-carotene and retinyl palmitate occurred maximally over the fourth to fifth hour postprandially. There was a correlation between the TRL concentrations of beta-carotene and retinyl palmitate (males r 0.62, P < 0.001; females r 0.52, P < 0.001) and there was no significant difference between men and women either in the total amount of beta-carotene appearing in the TRL fraction or in the amount converted to retinol. On estimation, approximately 1.4 mg of the 40 mg beta-carotene dose was absorbed and this was not significantly different from the amount of lycopene (1.0 mg) but significantly different (P < 0.05) from the amount of lutein (0.8 mg) absorbed, after correction for the smaller doses administered. There was approximately a twofold difference between subjects in the uptake of beta-carotene into the TRL fraction, a two- to threefold variation in lycopene and a two- to threefold variation in lutein. Despite these inter-subject differences, in three volunteers between whom there was a threefold difference in beta-carotene in the TRL fraction and a twofold difference in retinol formation, repeat experiments with beta-carotene 4 months later found differences of only 3-6% in the TRL beta-carotene content and 4-9% for the TRL retinol formed. In conclusion, large inter-subject variation in TRL carotene uptake precluded any differences between sexes but surprising intra-subject consistency was observed in TRL beta-carotene uptake of three subjects.

Adult↗
PubMed1996

A gene for autosomal dominant late-onset progressive non-syndromic hearing loss, DFNA10, maps to chromosome 6.

Late-onset non-syndromic hearing impairment is the most common type of neurological dysfunction in the elderly. It can be either acquired or inherited, although the relative impact of heredity on this type of loss is not known. To date, nine different genes have been localized, but none has been cloned. Using an extended American family in which a gene for autosomal dominant late-onset non-syndromic hearing impairment is segregating, we have identified a new locus, DFNA10, on chromosome 6.

Chromosome Mapping↗
PubMed1996

Rehearsal strategies and recall performance in boys with and without attention deficit hyperactivity disorder.

Examined differences in recall performance and rehearsal strategies in boys with Attention Deficit Hyperactivity Disorder (ADHD) and comparison boys using an overt rehearsal procedure on a self-paced, multitrial, free recall task. Boys with ADHD recalled fewer words, tended to spend less time rehearsing the items, and spent less time attempting to retrieve them. Although they did not rehearse items less frequently than comparison boys, they relied almost exclusively on repetition of single items. In contrast, comparison boys showed some evidence of using active, multi-item (cumulative) rehearsal. Despite their failure to use cumulative rehearsal, boys with ADHD identified it as more effective than single-item rehearsal in a subsequent forced-choice assessment of strategy knowledge.

Analysis of Variance↗
PubMed1996

Maternal rectal temperature and fetal heart rate responses to upright cycling in late pregnancy.

OBJECTIVE: To assess maternal rectal temperature and fetal heart rate responses to dynamic exercise. METHODS: 11 healthy women with low risk pregnancies completed three separate upright cycling tests at 34 to 37 weeks gestation: 15 min at 62.5 W (mean maternal heart rate [MHR] 138 beats.min-1 (test A); 15 min at 87.5 W (MHR 156 beats.min-1) (test B); and 30 min at 62.5 W (MHR 142 beats.min-1) (test C). Rectal temperature and fetal heart rate were measured. RESULTS: Mean temperature increase after tests B and C [by 0.4(SD 0.1) degrees C] was greater than after test A [0.2(0.1) degrees C] (P < 0.001). Fetal heart rate, measured in the recovery period immediately after exercise, increased significantly only after tests B and C (P < 0.01). Exercise related changes in temperature and fetal heart rate weakly correlated in tests B (P < 0.02) and C (P < 0.01). CONCLUSIONS: Temperature and fetal heart rate changes were more marked after higher intensity (test B) or longer duration exercise (test C) compared with moderate exercise, but none of the tests caused adverse fetal heart rate changes (decrease in accelerations, bradycardia, or decelerations) or individual temperatures above 38 degrees C.

Bicycling↗
PubMed1995

An autosomal recessive nonsyndromic form of sensorineural hearing loss maps to 3p-DFNB6.

Autosomal recessive nonsyndromic hearing loss (ARNSHL) is the most common form of congenitally acquired inherited hearing impairment. Although numerous loci are believed to exist, only five have been identified. Using a pooled genomic DNA screening strategy, we have identified a sixth locus, DFNB6, on 3p in the interval bounded by D3S1619 and D3S1766.

Alleles↗
PubMed1993

Intrathecal baclofen: does tolerance occur?

Concern over the development of tolerance in patients on continuous intrathecal baclofen therapy has arisen as this new form of treatment for spasticity has gained wider use. We have studied time-dose relationships in 18 spinal cord injured patients who have undergone intrathecal baclofen infusion pump implantation since February 1988 in our facility. Our data show that there was a significant increase in baclofen dosage needed to control spasticity during the first 12 months post implantation. After 12 months, however, no significant changes in dosage requirement was detected. In addition, there was no significant difference between completely and incompletely spinal cord injured patients with regard to both the initial dose and the tolerance trend.

Baclofen↗
PubMed1993

Cardiorespiratory response to walking in trained and sedentary pregnant women.

In order to test whether trained (n = 10) and sedentary (n = 29) pregnant women have different responses to weight-bearing exercise in the second trimester (range 23 to 28 weeks of gestation), subjects walked continuously on a treadmill for 26 minutes: at low intensity for 10 minutes, then an intermediate stage, followed by moderate intensity for 10 minutes. In the trained group, the mean heart rate was lower (p < 0.02) with both low [104.0 +/- 4.5 (SD) versus 117.4 +/- 2.3 bpm] and moderate intensity exercise (128.4 +/- 5.7 versus 145.2 +/- 2.9 bpm) and the associated mean stroke volume was higher (105 +/- 16 versus 84 +/- 17 ml; 103 +/- 15 versus 86 +/- 18 ml, respectively) (p < 0.02). The mean cardiac output, blood pressure and oxygen consumption were the same in the two groups (p > 0.02) at the same absolute workloads. The potential implications of these findings for exercise prescriptions for pregnant women, research evaluation and exercise testing are discussed.

Adult↗
PubMed1992

Accuracy of Borg's ratings of perceived exertion in the prediction of heart rates during pregnancy.

When using Borg's 6-20 scale during pregnancy, ratings of perceived exertion (RPE) did not significantly correlate with exercise heart rates (HR) (P greater than 0.05). The HR predicted from RPE significantly (P less than 0.05) underestimated the exercise HR in the second trimester during walking (Group 1: mean difference 16 beats min-1, n = 11), aerobics classes (Group 4: mean 15 beats min-1, n = 48) and circuit training (Group 3: mean 18 beats min-1, n = 24); and in the third trimester during cycling (Group 2: mean 16 beats min-1, n = 12) and aerobics classes (Group 5: mean 11 beats min-1, n = 29). Maximal individual HR under-estimations were large for each physical activity during pregnancy, with values up to 54 beats min-1. Consequently, exercise intensity should not be monitored solely with RPE during pregnancy.

Exercise Test↗
PubMed1991

Study strategies and story recall in attention deficit disorder and reading disability.

The role of metacognition and executive processes in mediating use of study skills was examined in groups of attention deficit disorder with hyperactivity (ADD-H), normal, and non-ADD-H reading-disabled (RD) boys, matched on age and verbal IQ. On a story recall task, ADD-H boys did not differ from normals in their immediate gist recall of a story or in their recall following a study period. RD boys demonstrated inferior recall in both conditions. Study skills of the ADD-H boys were poorer than those of normal boys on all measures. They spent less time studying, expended less effort, and employed more superficial strategies. However, their poor strategies did not appear to reflect a lack of metacognitive awareness. Results are discussed in terms of the impact of motivational variables in modulating strategy use in ADD-H boys and the impact of verbal processing problems in reading disabilities. Implications for treatment and the relationship between ADD-H and RD are discussed.

Achievement↗