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Biomedical subjects

J Hagan

Publications and source records attributed to J Hagan.

At least 19 recordsLinked to original sources
PubMed2006

Preschool healthcare utilisation related to home oxygen status.

OBJECTIVE: To determine, in prematurely born children who had bronchopulmonary dysplasia (BPD), if respiratory morbidity, healthcare utilisation, and cost of care during the preschool years were influenced by use of supplementary oxygen at home after discharge from the neonatal intensive care unit. DESIGN: Observational study. SETTING: Four tertiary neonatal intensive care units. PATIENTS: 190 children, median gestational age 27 weeks (range 22-31), 70 of whom received supplementary oxygen when discharged home. INTERVENTIONS: Review of hospital and general practitioner records together with a parent completed respiratory questionnaire. MAIN OUTCOME MEASURES: Healthcare utilisation, cost of care, cough, wheeze, and use of an inhaler. RESULTS: Seventy children had supplementary oxygen at home (home oxygen group), but only one had a continuous requirement for home oxygen beyond 2 years of age. There were no significant differences in the gestational age or birth weight of the home oxygen group compared with the rest of the cohort. However, between 2 and 4 years of age inclusive, the home oxygen group had more outpatient attendances (p = 0.0021) and specialist attendances (p = 0.0023), and, for respiratory problems, required more prescriptions (p<0.0001). Their total cost of care was higher (p<0.0001). In addition, more of the home oxygen group wheezed more than once a week (p = 0.0486) and were more likely to use an inhaler (p<0.0001). CONCLUSIONS: Children with BPD who have supplementary oxygen at home after discharge have increased respiratory morbidity and healthcare utilisation in the preschool years.

Birth Weight↗
PubMed2004

Health care utilisation of prematurely born, preschool children related to hospitalisation for RSV infection.

BACKGROUND: In prematurely born infants with chronic lung disease (CLD), RSV hospitalisation is associated with increased health service utilisation and costs in the first two years after birth. AIMS: To determine whether RSV hospitalisation in the first two years was associated with chronic respiratory morbidity during the preschool years in prematurely born children who had had CLD. METHODS: Retrospective review of readmissions, outpatient attendances, and community care in years 2-4 and, at age 5 years, assessment of the children's respiratory status and their health related quality of life. Comparison was made of the results of children who had had at least one hospitalisation in the first two years after birth for RSV infection (RSV group) to those of the rest of the cohort. Participants were 190 of an original cohort of 235 infants with CLD and a median gestational age 27 (range 22-33) weeks. RESULTS: The 33 children in the RSV group, compared to the rest of the cohort, had a greater duration of hospital stay and more outpatient appointments. The RSV group had required more prescriptions for all treatments and respiratory medications, and more had used an inhaler. The cost of care of the RSV group was higher (median 2630 pounds sterling [4000 Euros, US4800 dollars], range 124-18,091 pounds sterling versus 1360 pounds sterling [2500 Euros, US3000 dollars], range 5-18 929 pounds sterling ) and their health related quality of life was lower. CONCLUSION: In prematurely born children who had developed CLD, RSV hospitalisation in the first two years was associated with chronic respiratory morbidity and increased cost of care.

Ambulatory Care↗
PubMed2000

Implementation of a large-scale ENU mutagenesis program: towards increasing the mouse mutant resource.

Systematic approaches to mouse mutagenesis will be vital for future studies of gene function. We have begun a major ENU mutagenesis program incorporating a large genome-wide screen for dominant mutations. Progeny of ENU-mutagenized mice are screened for visible defects at birth and weaning, and at 5 weeks of age by using a systematic and semi-quantitative screening protocol-SHIRPA. Following this, mice are screened for abnormal locomotor activity and for deficits in prepulse inhibition of the acoustic startle response. Moreover, in the primary screen, blood is collected from mice and subjected to a comprehensive clinical biochemical analysis. Subsequently, secondary and tertiary screens of increasing complexity can be used on animals demonstrating deficits in the primary screen. Frozen sperm is archived from all the male mice passing through the screen. In addition, tail tips are stored for DNA. Overall, the program will provide an extensive new resource of mutant and phenotype data to the mouse and human genetics communities at large. The challenge now is to employ the expanding mouse mutant resource to improve the mutant map of the mouse. An improved mutant map of the mouse will be an important asset in exploiting the growing gene map of the mouse and assisting with the identification of genes underlying novel mutations-with consequent benefits for the analysis of gene function and the identification of novel pathways.

Animals↗
PubMed2000

A systematic, genome-wide, phenotype-driven mutagenesis programme for gene function studies in the mouse.

As the human genome project approaches completion, the challenge for mammalian geneticists is to develop approaches for the systematic determination of mammalian gene function. Mouse mutagenesis will be a key element of studies of gene function. Phenotype-driven approaches using the chemical mutagen ethylnitrosourea (ENU) represent a potentially efficient route for the generation of large numbers of mutant mice that can be screened for novel phenotypes. The advantage of this approach is that, in assessing gene function, no a priori assumptions are made about the genes involved in any pathway. Phenotype-driven mutagenesis is thus an effective method for the identification of novel genes and pathways. We have undertaken a genome-wide, phenotype-driven screen for dominant mutations in the mouse. We generated and screened over 26,000 mice, and recovered some 500 new mouse mutants. Our work, along with the programme reported in the accompanying paper, has led to a substantial increase in the mouse mutant resource and represents a first step towards systematic studies of gene function in mammalian genetics.

Animals↗
PubMed1999

Children and electronic games: a comparison of parents' and children's perceptions of children's habits and preferences in a United States sample.

Despite the popularity of violent electronic games, anecdotal evidence suggests that many parents lack even basic information about children's game-playing habits. The goal of the present study was to examine parental knowledge of children's electronic game-playing habits by assessing the congruence between children's and parents' perceptions of child's playing time, parental supervision, game preference, and reaction to actual game-playing. 35 children in Grades 3 to 5 and one parent of each child completed a background questionnaire and played either a violent or nonviolent electronic game. In paired comparisons, parents reported significantly higher estimates of supervision time than children. Most parents either named an incorrect game or were not able to guess their child's favorite game. In 70% of these incorrect matches, children described their favorite game as violent. Parents may underestimate their child's exposure to violence in electronic games. After playing the same electronic game as part of the study, parents reported significantly higher frustration than children. Higher frustration with game-playing could contribute to deficits in parental knowledge of children's playing habits.

Adult↗
PubMed1999

Death at the border.

"Debates about United States border control policies have generally ignored the human costs of undocumented migration. We focus attention on these costs by estimating the number, causes and location of migrant deaths at the southwest border of the United States between 1993 and 1997.... Deaths from hyperthermia, hypothermia and dehydration increased sharply from 1993 to 1997 as intensified border enforcement redirected undocumented migration flows from urban crossing points to more remote crossing areas where the migrants are exposed to a greater risk of death."

Americas↗
PubMed1998

5-HT4 receptor antagonism does not affect motor and reward mechanisms in the rat.

5-HT4 receptors are concentrated in areas of the brain which are rich in dopamine neuronal markers, which may suggest that they influence motor and reward processes. We tested this hypothesis by examining the effects of a 5-HT4 receptor antagonist, 8-amino-7-chloro-(N-butyl-4-piperidyl)methylbenzo-1,4-dioxan-5-car boxylate hydrochloride (SB-204070-A) on amphetamine- and nicotine-induced locomotor stimulation in intact rats. In rats with unilateral 6-hydroxydopamine-induced lesions of the ascending nigrostriatal dopaminergic projection, SB-204070-A was tested for its effects on amphetamine-induced rotation. SB-204070-A was also tested for its effects on rewarded behaviour maintained by intracranial self-stimulation. SB-204070-A did not alter behaviour under any of these conditions, suggesting a lack of involvement of the 5-HT4 receptor in motor and reward processes.

Amphetamine↗
PubMed1998

Functional characterisation of the human cloned 5-HT7 receptor (long form); antagonist profile of SB-258719.

1. The functional profile of the long form of the human cloned 5-HT7 receptor (designated h5-HT7(a)) was investigated using a number of 5-HT receptor agonists and antagonists and compared with its binding profile. Receptor function was measured using adenylyl cyclase activity in washed membranes from HEK293 cells stably expressing the recombinant h5-HT7(a) receptor. 2. The receptor binding profile, determined by competition with [3H]-5-CT, was consistent with that previously reported for the h5-HT7(a) receptor. The selective 5-HT7 receptor antagonist SB-258719 ((R)-3,N-Dimethyl-N-[1-methyl-3-(4-methylpiperidin-1-yl)propyl]ben zene sulfonamide) displayed high affinity (pKi 7.5) for the receptor. 3. In the adenylyl cyclase functional assay, 5-CT and 8-OH-DPAT were both full agonists compared to 5-HT and the rank order of potency for agonists (5-CT > 5-HT > 8-OH-DPAT) was the same in functional and binding studies. 4. Risperidone, methiothepin, mesulergine, clozapine, olanzapine, ketanserin and SB-258719 antagonised surmountably 5-CT-stimulated adenylyl cyclase activity. Schild analysis of the antagonism by SB-258719 gave a pA2 of 7.2+/-0.2 and slope not significantly different from 1, consistent with competitive antagonism. 5. The same antagonists also inhibited basal adenylyl cyclase activity with a rank order of potency in agreement with those for antagonist potency and binding affinity. Both SB-258719 and mesulergine displayed apparent partial inverse agonist profiles compared to the other antagonists tested. These inhibitory effects of antagonists appear to be 5-HT7 receptor-mediated and to reflect inverse agonism. 6. It is concluded that in this expression system, the h5-HT7(a) receptor shows the expected binding and functional profile and displays constitutive activity, revealing inverse agonist activity for a range of antagonists.

Adenylyl Cyclases↗
PubMed1997

Domain organization of calbindin D28k as determined from the association of six synthetic EF-hand fragments.

Calbindin D28k is an intracellular Ca(2+)-binding protein containing six subdomains of EF-hand type. The number and identity of the globular domains within this protein have been elucidated using six synthetic peptide fragments, each corresponding to one EF-hand subdomain. All six peptides were mixed in equimolar amounts in the presence of 10 mM Ca2+ to allow for the reconstitution of domains. The mixture was compared to native calbindin D28k and to the sum of the properties of the individual peptides using circular dichroism (CD), fluorescence, and 1H NMR spectroscopy, as well as gel filtration and ion-exchange chromatography. It was anticipated that if the peptides associate to form native-like domains, the properties would be similar to those of the intact protein, whereas if they did not interact, they would be the same as the properties of the isolated peptides. The results show that the peptides in the mixture interact with one another. For example, the CD and fluorescence spectra for the mixture are very similar to those of the intact calbindin D28k, suggesting that the mixed EF-hand fragments associate to form a native-like structure. To determine the number of domains and the subdomain composition of each domain in calbindin D28k, a variety of peptide combinations containing two to five EF-hand fragments were studied. The spectral and chromatographic properties of all the mixtures containing less than six peptides were closer to the sum of the properties of the relevant individual peptides than to the mixture of the six peptides. The results strongly suggest that all six EF-hands are packed into one globular domain. The association of the peptide fragments is observed to drive the folding of the individual subdomains. For example, one of the fragments, EF2, which is largely unstructured in isolation even in the presence of high concentrations of Ca2+, is considerably more structured in the presence of the other peptides, as judged by CD difference spectroscopy. The CD data also suggest that the packing between the individual subdomains is specific.

Amino Acid Sequence↗
PubMed1995

Adhesiveness of human ligament fibroblasts to laminin.

The adhesiveness of fibroblasts from the human anterior cruciate and medial collateral ligaments to the laminin molecule was studied, with particular emphasis on the intrinsic differences between fibroblasts from the two ligaments. Cellular adhesion strength, adhesion area, laminin concentration, and seeding time were examined. Cell adhesion to laminin anchored with poly-D-lysine to a cleaned cover glass was measured with a micropipette micromanipulation system after seeding. The adhesion strength of fibroblasts from the anterior cruciate ligament to laminin was greater than and significantly different from that of fibroblasts from the medial collateral ligament, depending on the laminin concentration. Fibroblasts from the anterior cruciate ligament also exhibited an increase in adhesion strength, dependent on laminin concentration of as much as 30 micrograms/ml, at which the laminin receptors were thought to be saturated. Fibroblasts from the medial collateral ligament did not show such an increase except at laminin concentrations of 5-10 micrograms/ml. There was no significant difference in adhesion area between fibroblasts from the two ligaments except after 45 minutes at a laminin concentration of 40 micrograms/ml. For both, the adhesion to laminin showed little correlation to seeding time during periods of as long as 60 minutes. Measurements of adhesion area also failed to show a significant correlation to seeding time for fibroblasts from either ligament at laminin concentrations of 20 and 40 micrograms/ml. Adhesion strength normalized by adhesion area had no correlation to seeding time.(ABSTRACT TRUNCATED AT 250 WORDS)

Anterior Cruciate Ligament↗
PubMed1995

Establishing partnerships with family caregivers. Local and cosmopolitan knowledge.

Families now provide most of the care received by older people in the United States. Proposed changes in the health care system will mean that families must take an even greater role in delivering health care. It is crucial that nurses practicing in a variety of settings be prepared to establish partnerships with family caregivers in order to attend to the long-term care needs of older people.

Aged↗
PubMed1994

Establishing partnerships with family caregivers. Local and cosmopolitan knowledge.

1. The concepts of local and cosmopolitan knowledge may be used by gerontological nurses in creating partnerships with family caregivers to frail older people. 2. Local knowledge is the understanding and skills that the family brings to the caregiving situation; cosmopolitan knowledge is the understanding and skills that the gerontological nurse brings to the situation. 3. Four nursing interventions are guided by the conceptualization of local and cosmopolitan knowledge: acknowledging and affirming local knowledge when it is adequate; developing or enhancing local knowledge when it is inadequate; assisting family caregivers to apply local knowledge to problem solving; and blending local and cosmopolitan knowledge.

Aged↗
PubMed1992

Behavioral screening for cognition enhancers: from indiscriminate to valid testing: Part I.

Preclinical efforts to detect and characterize potential cognition enhancers appear to have been dominated by a strategy of demonstrating a wide variety of apparently beneficial behavioral effects with little attention given to the specific psychological mechanisms underlying behavioral enhancement. In particular, the question of whether or not behavioral facilitation is based on relevant mnemonic mechanisms and is independent of the stimulus properties and/or the motivational and attentional components of a task is not often considered. As a result, an overwhelming number of compounds have failed to produce the clinical effects predicted for them on the basis of preclinical research. The available data suggest that a more successful approach requires deductive research strategies rather than the indiscriminate accumulation of apparently beneficial effects in a variety of behavioral tasks and animal models. The first step towards such an approach is a systematic and rigorous evaluation of the different aspects of validity for the models most frequently used in preclinical research. It is concluded that a combination of good construct validity and good face validity represents a necessary condition for screening tests with predictive validity, and that the most popular paradigms fail to fulfil these criteria. Future screening programs for cognition enhancers will probably be characterized by a depreciation of "fast and dirty tests" in favor of approaches focussing on the validity of the effects of potential cognition enhancers.

Animals↗
PubMed1992

Airway obstruction following transhiatal esophagogastrectomy.

A 79 year old man suffered acute respiratory distress secondary to delayed gastric emptying several months following esophagogastrostomy. No drainage procedure was performed at the time of the procedure. The need for a drainage procedure is controversial. Symptoms of gastric stasis have reportedly improved with a drainage procedure and the risk of concomitant pyloromyotomy or pyloroplasty has been shown to be minimal and may prevent a potentially catastrophic complication as described in this report.

Aged↗
PubMed1992

Streetlife and delinquency.

The correlation between class and delinquency often observed in areal studies and assumed in prominent sociological theories is elusive in studies of individuals commonly used to test these theories. A restricted conceptualization of class in terms of parental origins and the concentration of self-report survey designs on adolescents in school have removed from this area of research street youth who were once central to classic studies of delinquency. We argue that street youth experience current class conditions that cause serious delinquency, and that life on the street is an important intervening variable that transmits indirect effects of control and strain theory variables, including parental class origins. Data gathered from nearly 1000 Toronto school and street youth are analyzed with important implications for the conceptualization of class and delinquency, testing and integrating sociological theories of delinquency, the measurement of delinquency, and the use of cross-sectional and longitudinal research designs. Our findings especially encourage incorporation of street-based samples into research on class-based aspects of theories of delinquency.

Adolescent↗
PubMed1989

Lipids: impact on dietary prescription in diabetes.

The rate of death from coronary artery disease is two to three times higher among individuals with diabetes than among their age- and sex-matched peers. In diabetes, many factors may affect blood lipid levels and complicate formulating an effective dietary prescription. Both Type I and Type II diabetes may have an independent effect on lipids. This article discusses metabolic derivations in carbohydrate and lipid metabolism that contribute to lipid abnormalities. The National Cholesterol Education Program Guidelines, which include dietary recommendations for lowering blood lipid levels by modifying fat intake, are discussed in regard to their effect on blood lipids in diabetes and their effect on other variables, such as blood glucose control. Other treatment approaches common in diabetes and lipid management include low-calorie diets and weight reduction, a change in the fatty acid composition of the diet, and high-carbohydrate diets. An evaluation of the etiologies of lipid abnormalities and interventions directed toward lipid levels and other indexes of diabetes management may lead to improved lipid levels, improved blood glucose control, and avoidance of unnecessary, ineffective, or deleterious dietary prescriptions for individuals with diabetes.

Coronary Disease↗