Search PubMed⌕ Search

Biomedical subjects

A C Ferguson

Publications and source records attributed to A C Ferguson.

At least 19 recordsLinked to original sources
PubMed1995

A body-worn gait analysis system for evaluating hemiplegic gait.

This paper describes a system for measuring the temporal parameters of hemiplegic gait. This system uses shoe insoles with sensors, acting as switches, placed under the heel, head of the first metatarsal, head of the fifth metatarsal and the big toe. This system is able to monitor gait for up to 10 min and can be used by the patient over any surface. Parameters for evaluating hemiplegic gait are defined, including scuffing during swing and the degree of inversion during stance.

Cerebrovascular Disorders↗
PubMed1995

Evaluation of serum eosinophilic cationic protein as a marker of disease activity in chronic asthma.

BACKGROUND: Serum eosinophil cationic protein (ECP) has been promoted as a direct marker of eosinophilic inflammation of the bronchi, especially helpful in patients with asymptomatic asthma. OBJECTIVE: To evaluate serum ECP against indirect clinical markers of disease activity, we compared symptom score, bronchial obstruction, bronchial responsiveness, and blood eosinophil counts with serum ECP levels in children with symptomatic and asymptomatic chronic asthma and assessed ECP in others with allergic rhinitis alone. METHODS: Twenty-four children with symptomatic asthma, 10 children with asymptomatic asthma, and 16 children with allergic rhinitis were studied. Measurements were made by standardized symptom questionnaire, spirometry, inhalation challenge with histamine or methacholine, blood eosinophil counts, and radioimmunoassay of serum ECP. RESULTS: There was no difference in serum ECP levels between the symptomatic asthma, asymptomatic asthma, or rhinitis groups, and most values were within the normal range. Activated eosinophil counts were higher in subjects with symptomatic asthma than in those with asymptomatic asthma but not in subjects with rhinitis. Serum ECP correlated with eosinophil counts (p < 0.01) but not symptom score, forced expiratory volume in 1 second (FEV1), forced expiratory flow, mid-expiratory phase (FEF25-75), or provocative concentration causing a 20% fall in FEV1 (PC20). Symptom scores correlated with PC20 (p < 0.005) and FEF25-75 (p < 0.01). CONCLUSION: Serum ECP is a poor indicator of disease activity in chronic asthma and cannot differentiate bronchial from nasal inflammation.

Adolescent↗
PubMed1993

Hypersensitivity reaction to single contrast barium meal studies in children.

We report two children who developed hypersensitivity reactions of varying severity following barium meal examination, the more severe of which was associated with documented severe food allergy. For children with this risk factor, contrast studies should be performed only where facilities and personnel are available for immediate resuscitation of all sizes of child. For children such as these, consideration should be given to the use of pure barium sulphate.

Barium Sulfate↗
PubMed1992

Correlation of bronchial eosinophil and mast cell activation with bronchial hyperresponsiveness in children with asthma.

Bronchial hyperresponsiveness in asthma has been associated with increased numbers of eosinophils and mast cells in the bronchial airway. It is unclear if these cells are important in the pathogenesis of hyperresponsiveness, and the role of mast cells has been discounted because they are effectively stabilized by beta-adrenergic drugs. Because the pathogenesis of asthma in children may be different from that in adults, and to find out if cellular activation is associated with bronchial reactivity, we studied 17 children with mild to moderately severe chronic asthma who had been treated with intermittent brochodilator therapy and compared their bronchial responsiveness to histamine with the levels of eosinophil cationic protein and mast cell tryptase in broncholavage fluid. The number of eosinophils in lavage fluid was correlated with histamine responsiveness (r = -0.444, p < 0.05) but not with levels of cationic protein (r = 0.33, p = NS). Bronchial responsiveness to histamine was highly correlated with mast cell tryptase (r = -0.714, p < 0.005), but there was no correlation with eosinophil cationic protein (r = -0.355, p = NS). We conclude that in children with chronic asthma mast cells as well as eosinophils contribute to bronchial hyperresponsiveness. Activated mast cells may play a primary role, possibly by tryptase-induced upregulation of bronchial smooth muscle tone.

Adolescent↗
PubMed1992

Reduction of seating pressure using FES in patients with spinal cord injury. A preliminary report.

The aim of this study was to investigate the use of functional electrical stimulation (FES) as a means of pressure sore prevention in seated spinal cord injured (SCI) subjects. Nine SCI subjects took part in tests in which electrical stimulation was applied to the quadriceps with the lower legs restrained. Ischial pressures were measured during periods of quiet sitting and FES application. A strain gauged lever arm was used to measure the knee moment during quadriceps stimulation. The average pressure drop at the right and left buttocks was 44 mmHg and 27 mmHg respectively. In general the greatest reductions occurred in subjects with larger knee moments; however, there was no direct relationship between the pressure reduction obtained and the quadriceps strength. This form of FES may be useful as a prophylactic aid in the management of pressure sores in SCI subjects.

Adult↗
PubMed1989

Bronchial hyperresponsiveness in asthmatic children. Correlation with macrophages and eosinophils in broncholavage fluid.

Bronchial responsiveness assessed by histamine bronchial challenge testing in 22 children with chronic stable asthma was compared with the number of inflammatory cells per milliliter of broncholavage fluid obtained by fiberoptic bronchoscopy. Hyperresponsiveness was closely correlated with increased counts of eosinophils and macrophages and with the ratio of eosinophils to macrophages. There was no correlation of neutrophil or lymphocyte counts with bronchial hyperresponsiveness and none of the cell types was correlated with airway obstruction. Our findings support the hypotheses that macrophages may be important in the development of bronchial hyperresponsiveness in children with asthma and that they may modulate bronchial responsiveness both directly and by recruitment of eosinophils.

Asthma↗
PubMed1989

A comparison of chiropractic, medical and osteopathic care for work-related sprains and strains.

The cost of care and the number of days lost because of work injury were analyzed from information gathered in a postal card survey sent to all Iowa back or neck injury claimants (sprain/strain) on record for 1984. Descriptive findings for the flow of care of the respondents were evaluated and a comparison made of the benefits and costs of care received by patients treated by chiropractic doctors (DCs), medical doctors (MDs) or osteopathic doctors (DOs). The analysis focused on those workers who lost enough time from work to qualify for compensation (4 days or more), whose cases were closed and who received all their care from one health professional. For those who received care from DCs (n = 266), the mean number of compensated days lost from work was at least 2.3 days less than for those who were treated by MDs (n = 494; p less than 0.025) and at least 3.8 days less than for those who were treated by DOs (n = 102; p less than 0.025). Consequently, much less money in employment compensation was paid, on the average, to those who saw DCs. Findings on provider care costs are less clear-cut because care-cost data on only a portion of the cases was recorded on the State records used. For the data available, the median provider cost was highest for patients who saw DCs, but the mean was highest for those who saw MDs. The study showed that 38% of claimants did change doctors. When change of provider occurred, days lost from work and cost of care varied widely across the care options, but generally, fewer workdays were lost and lower amounts of disability compensation and provider cost paid when chiropractic was included in the care pattern.

Absenteeism↗
PubMed1988

Persisting airway obstruction in asymptomatic children with asthma with normal peak expiratory flow rates.

Twice-daily symptom scores and peak expiratory flow readings were compared with spirometric values (FEV1 and forced expiratory flow rate between 25% and 75% of FVC [FEF 25-75]) measured at 2-week intervals in assessing airway obstruction in 20 children with asthma studied during 16 weeks. Of 56 2-week periods during which symptoms were absent, peak flow was decreased in 30 (54%), FEV1 in 20 (36%), and FEF 25-75 in 37 periods (66%). Peak flow readings were normal in 13 of 70 periods (16%) in which FEV1 was decreased, and in 33 of 113 periods (29%), in which FEF 25-75 was decreased. Of 25 periods in which symptoms were absent and peak flow was normal, 19 (76%) were associated with decreased FEF 25-75. The results confirm previous studies that indicate peak flow readings are a useful addition to symptom diaries. More importantly, they demonstrate that airway obstruction may be present in a large proportion of asymptomatic children with asthma who have normal peak flow rates and suggest that frequent assessment of FEF 25-75 is required, as well as daily monitoring of symptoms and peak flow both in trials of drug therapy and for more optimal assessment of the effectiveness of therapy in clinical practice.

Adolescent↗
PubMed1986

Predictive value of skin prick tests and radioallergosorbent tests for clinical allergy to dogs and cats.

The predictive value and post-test probability of disease were compared for skin prick tests and radioallergosorbent tests (RASTs) in 168 children suspected of clinical allergy to dogs and cats. The skin tests included negative and positive (histamine) controls. The results of RASTs with the same allergen extracts were expressed in relation to the results with allergen-specific pooled reference serum. All the tests were performed blind. The predictive values of positive test results were comparable and low (53% to 76%), whereas the predictive values of negative test results were comparable and high (88% to 95%). The post-test probability of clinical allergy to dog or cat allergen, based on the prevalence rates in the referral population (15.1% and 22.5% respectively), increased to between 46% and 67% for positive test results and decreased to between 4% and 8% for negative results, which suggests that the primary role of skin prick tests and RASTs is in eliminating the diagnosis of clinical allergy.

Adolescent↗
PubMed1985

Sensitization to house dust mites in different climatic areas.

With the use of local meteorologic data, the mean monthly indoor relative humidity (RH) was calculated for the area of residence of each of 774 children with respiratory symptoms who were referred to our allergy clinic. Seven hundred fourteen children lived in areas in which the mean indoor RH was 50% or more for 4 or more mo per year ("humid" areas), and 60 children lived where this RH was present for no more than 2 mo per year ("dry" areas). Of those children from the "humid" areas, the skin prick test was positive to Dermatophagoides farinae in 31% and D. pteronyssinus in 40%, whereas in those children from "dry" areas, tests were positive in 3% and 2%, respectively, (p less than 0.001). There was also a marked difference in the degree of sensitivity. In those children with a positive RAST (more than 12% of binding relative to allergen-specific pooled reference sera), the mean level of binding was 51% +/- 3.5% for D. farinae and 62% +/- 4.4% for D. pteronyssinus in children from "humid" areas but never exceeded 14% for either species in those children from "dry" areas (p less than 0.001). Sensitivity to D. farinae and D. pteronyssinus is frequent in "humid" areas and seldom, if it is ever, occurs in areas that are "dry," either as a result of a semiarid climate or a prolonged heating season. These findings have implications for the etiologic diagnosis and specific treatment of atopic patients living in different climatic regions.

Child↗
PubMed1984

Elevated IgG immune complexes in children with atopic eczema.

The levels of serum IgG complement-fixing immune complexes were studied in 20 children with atopic eczema and in 10 children with allergic rhinitis as control subjects with the use of a Raji cell assay. Immune-complex levels were strikingly elevated in those with eczema, 50 +/- 10 SE micrograms/ml, compared to control subjects 11 +/- 9 micrograms/ml (p less than 0.0047), the latter falling within the range for nonallergic subjects. Levels tended to be higher in those subjects with more severe eczema, but there was no statistically significant correlation, nor were levels correlated with serum IgE. Sucrose-density gradient analysis demonstrated the immune complexes to be present in two peaks, 8 to 10S and 21S or higher. High-molecular-weight IgG immune complexes that are complement-fixing may promote the characteristic pruritus of eczema by formation of anaphylactic complement fragments and the release of inflammatory substances from cutaneous mast cells, as well as contributing to the impaired cell-mediated immunity associated with the disease.

Antigen-Antibody Complex↗
PubMed1984

Food allergy.

Adverse clinical reactions to food associated with disturbed immunologic function (food allergy) affect 1-3% of the population and vary from life-threatening to a minor inconvenience. They must be differentiated from reactions caused by toxins, pharmacologic agents, enzyme deficiences and non-specific release of inflammatory mediator substances. Enteric absorption of food protein antigens which may occur despite an array of gastrointestinal protective mechanisms normally induces both a protective immune response and immunologic tolerance. Quantitative changes in absorption related to deficient protective mechanisms or excessive antigen load may contribute to the development of an allergic immune response and explain the greater incidence of food allergy in infants and children. Important factors include immunologic immaturity, enhanced macromolecular mucosal transport, intrauterine and neonatal malnutrition, breast feeding and infection. Double-blind food challenge tests remain as the most definitive diagnostic yardstick but carefully standardized skin tests may be helpful if interpreted in the context of the clinical history. Despite the association of food allergy with food antigen specific IgE hypersensitivity, immune complex formation and lymphocyte sensitization the pathophysiological changes which result in symptoms remain obscure. Recent advances have clarified many aspects of our knowledge of food allergy but inevitably have raised many more questions for future study.

Adolescent↗
PubMed1983

The frequency and severity of cat allergy vs. dog allergy in atopic children.

Questions were put to parents accompanying 1238 children, 1 to 17 yr old, who had symptoms of respiratory tract allergy. Skin prick tests were then performed. Symptoms after exposure to cats and positive skin test results from cat hair extract were significantly more frequent than symptoms after exposure to dogs or reactions to dog hair extract. The prevalence of symptoms and positive skin test reactions to cat allergens increased with age, significantly more so than the reaction or symptoms after exposure to dog allergens. The greater frequency of sensitivity to cats was not caused by exposure to cats in more homes, since dogs significantly outnumbered cats as the household pet in both atopic and nonatopic families. However, greater intimacy of exposure to cats when they were present may have been a factor because cats, significantly more often than dogs, were inside the house and in the child's bedroom. Two subgroups were examined to determine whether those with cat sensitivity who owned cats had more severe symptoms than those with dog sensitivity who owned dogs. Numbers were small and differences not statistically significant, but those in the cat subgroup more frequently had persistent allergic nasal symptoms and abnormally low spirometric measurements than did those in the dog subgroup. Our findings indicate that children are more often allergic to cats than to dogs and suggest that the greater frequency of sensitization to cats may be due to increased intimacy of exposure to cats.

Adolescent↗
PubMed1983

Diagnosis of house dust mite allergy in asthmatic children: what constitutes a positive history?

Standardized questions were put to the parents of 530 children, referred consecutively for evaluation of asthma, to determine which features in the history were associated with house-dust mite allergy. Bronchial challenge tests performed on 19 of the children confirmed that there is a highly significant association between a positive skin prick test and a positive bronchial challenge test to Dermatophagoides farinae mite antigen. One hundred and eighteen (23%) of the children had positive prick tests to the mite. There is a highly significant association between a positive prick test to mite and a history that the subject's respiratory symptoms become worse when there is exposure to domestic activity that stirs up house dust (vacuuming, dusting, sweeping, making the bed, or shaking out blankets) or that the symptoms improve when out of doors. Seasonal variation and other features in the history are of little value in distinguishing mite-sensitive from mite-insensitive asthmatics. Although the 4% whose only positive prick test reaction was to mite had significant worsening of asthma during the colder months compared with the remainder, most mite-positive subjects had multiple allergies and had no characteristic seasonal pattern. The presence of a positive prick test to mite was not associated with aggravation of asthma either at night in bed or in the morning on awakening. A history similar to that of mite-sensitive subjects was elicited in those with a positive prick test to house dust. A positive history of house dust or house-dust mite allergy in asthmatics is one in which respiratory symptoms become worse during domestic activity that stirs up house dust or improve when outdoors.

Adolescent↗
PubMed1983

Dust-free bedrooms in the treatment of asthmatic children with house dust or house dust mite allergy: a controlled trial.

Twenty asthmatic children with prick tests positive for house dust or house dust mites were allocated to two groups that were matched for severity. One group was provided with zippered vinyl covers for pillows, mattresses, and box springs, and instructions for making the bedroom as easy to keep clean as a hospital ward; the other group was not. At the end of a 1-month study period, there was a marked and statistically significant difference in symptoms and signs of asthma between the two groups. Those with a dust-free bedroom had fewer days on which wheezing was observed, medication was given, or an abnormally low peak expiratory flow rate was recorded. Bronchial tolerance to aerosolized histamine significantly improved in the group whose bedrooms had been modified. A dust-free bedroom diminishes bronchial irritability and is a practical and effective method for decreasing asthma in children with house dust or house dust mite allergy.

Asthma↗