PubMed Health⌕ Search

Biomedical subjects

R A Wood

Publications and source records attributed to R A Wood.

At least 19 recordsLinked to original sources
PubMed2001

Food-allergic reactions in schools and preschools.

BACKGROUND: Food allergies may affect up to 6% of school-aged children. OBJECTIVES: To conduct a telephone survey to characterize food-allergic reactions in children (defined as those aged 3-19 years in this study) with known food allergies in schools and preschools and to determine mechanisms that are in place to prevent and treat those reactions. DESIGN: The parents of food-allergic children were contacted by telephone and asked about their child's history of food-allergic reactions in school. The schools the children attended were contacted, and the person responsible for the treatment of allergic reactions completed a telephone survey. RESULTS: Of 132 children in the study, 58% reported food-allergic reactions in the past 2 years. Eighteen percent experienced 1 or more reactions in school. The offending food was identified in 34 of 41 reactions, milk being the causative food in 11 (32%); peanut in 10 (29%); egg in 6 (18%); tree nuts in 2 (6%); and soy, wheat, celery, mango, or garlic in 1 (3%) each. In 24 reactions (59%), symptoms were limited to the skin; wheezing occurred in 13 (32%), vomiting and/or diarrhea in 4 (10%), and hypotension in 1 (2%). Also, 15 (36%) of the 41 reactions involved 2 or more organ systems, and 6 (15%) were treated with epinephrine. Fourteen percent of the children did not have a physician's orders for treatment, and 16% did not have any medications available. Of the 80 participating schools, 31 (39%) reported at least 1 food-allergic reaction within the past 2 years and 54 (67%) made at least 1 accommodation for children with a food allergy, such as peanut-free tables, a peanut ban from the classroom, or alternative meals. CONCLUSIONS: It is common for food-allergic children to experience allergic reactions in schools and preschools, with 18% of children having had at least 1 school reaction within the past 2 years. Thirty-six percent of the reactions involved 2 or more organ systems, and 32% involved wheezing. Every effort should be made to prevent, recognize, and appropriately treat food-allergic reactions in schools.

Adolescent↗
PubMed2001

Cockroach allergen abatement with extermination and sodium hypochlorite cleaning in inner-city homes.

BACKGROUND: Although the importance of cockroach allergen in chronic asthma has now been well defined, little progress has been made in the control of cockroach allergen in infested homes. OBJECTIVE: The objective of this study was to examine the ability of a combination of professional pest extermination and household cleaning using a solution of sodium hypochlorite to reduce cockroach infestation and allergen levels in cockroach infested homes. METHODS: Seventeen cockroach-infested homes were studied with three homes serving as controls. In the intervention homes, a professional exterminator applied 0.05% abamectin twice at 2-week intervals at study entry and a professional cleaner cleaned the homes before and after the extermination. All washable surfaces were cleaned throughout the study with a solution of 0.5% hypochlorite. Monthly home visits were conducted to inspect the home, interview the homeowner, place passive cockroach traps, and to collect settled dust samples from the kitchen, bedroom, and TV/living room. RESULTS: The number of cockroaches in the passive traps decreased rapidly after the initial intervention in most homes. Median Blatella germanica allergen 1 levels in the settled dust samples fell by 91% in the kitchen, 78% in the bedroom, and 77% in the living room over the course of the study in the intervention homes but gradually rose in the control homes. The overall reductions were very similar to those seen in a previous study with a similar protocol except for the use of the sodium hypochlorite. CONCLUSIONS: Successful extermination is possible in most inner-city homes and cockroach allergen levels can be reduced by 80% to 90%. However, 0.5% sodium hypochlorite did not seem to improve allergen reduction, and in many homes, allergen levels remained above the proposed threshold of 8 U/g of dust throughout the study.

Air Pollution, Indoor↗
PubMed2001

The natural history of peanut allergy.

BACKGROUND: It has traditionally been assumed that peanut allergy is rarely outgrown. OBJECTIVE: The goal of this study was to determine the number of children with peanut allergy who become tolerant of peanut. METHODS: Patients aged 4 to 20 years with a diagnosis of peanut allergy were evaluated by questionnaire, skin testing, and a quantitative antibody fluorescent-enzyme immunoassay. Patients who had been reaction free in the past year and had a peanut IgE (PN-IgE) level less than 20 kilounits of antibody per liter (kU(A)/L) were offered an open or double-blind, placebo-controlled peanut challenge. RESULTS: A total of 223 patients were evaluated, and of those, 85 (PN-IgE < 0.35-20.4 kU(A)/L [median 1.42 kU(A)/L]) participated in an oral peanut challenge. Forty-eight (21.5%) patients had negative challenge results and were believed to have outgrown their peanut allergy (aged 4-17.5 years [median 6 years]; PN-IgE < 0.35-20.4 kU(A)/L [median 0.69 kU(A)/L]). Thirty-seven failed the challenge (aged 4-13 years [median 6.5 years]; RAST < 0.35-18.2 kU(A)/L [median 2.06 kU(A)/L]). Forty-one patients with PN-IgE levels less than 20 kU(A)/L declined to undergo challenge, and 97 were not eligible for challenge because their PN-IgE levels were greater than 20 kU(A)/L or they had had a recent reaction. Sixty-seven percent of patients with PN-IgE levels less than 2 kU(A)/L and 61% with levels less than 5 kU(A)/L had negative challenge results. Of those who underwent challenge, PN-IgE levels for those who passed versus those who failed were different at the time of challenge (P = .009), but not at the time of diagnosis (P = .25). CONCLUSION: This study demonstrates that peanut allergy is outgrown in about 21.5% of patients. Patients with low PN-IgE levels should be offered a peanut challenge in a medical setting to demonstrate whether they can now tolerate peanuts.

Adolescent↗
PubMed2001

The role and remediation of animal allergens in allergic diseases.

Animal allergens are common causes of both acute and chronic allergic disease. The most important animal allergens are derived from mammals, principally cats, dogs, rats, mice, horses, and cows, which secrete or excrete allergens into the environment. Allergic sensitization may occur at home or in the workplace. Cat and dog allergens commonly cause allergies in the home and affect the general population. Laboratory animal handlers often have allergic reactions to rats and mice. Cow dander allergy is usually caused by occupational exposure and occurs in farmers and farm workers. Horse allergy occurs among people who regularly handle horses, either professionally or for recreational purposes. Over the past 20 years, the major animal allergens have been defined and characterized with regard to their molecular structure, immunogenicity, and environmental distribution. One remarkable finding has been the fact that most of the mammalian allergens that have thus far been cloned belong to a single family of proteins called the lipocalins. In addition to these molecular similarities, it has also been shown that most of the animal allergens are quite similar with regard to their aerodynamic properties. Although much is yet to be learned, progress is being made in our knowledge regarding the steps that may be necessary to control exposure to these allergens through environmental modifications in both homes and occupational settings. These measures include source control, air filtration devices, barrier devices, removal of carpeting and other reservoirs, and, in some cases, washing of the animal.

Allergens↗
PubMed2001

Laboratory animal allergens.

Allergic sensitivity to laboratory animals can pose a significant occupational hazard to anyone with regular animal contact. Reactions to mice and rats are most common although all furred animals produce allergens that can lead to sensitization and disease. Most of the relevant allergens of laboratory animals have been defined and characterized, which has revealed that these allergens are typically small, acidic glycoproteins and that many of them are members of a superfamily of extracellular proteins called lipocalins. In addition to understanding their molecular characteristics, the identification of these allergens has also made it possible to measure their distribution in laboratory environments and to relate exposure levels to sensitization and symptoms. These studies have shown that the major laboratory animal allergens are carried on small particles that are both capable of remaining airborne for extended periods and penetrating into the lower airways of exposed workers. These advances in the understanding of these important occupational allergens will allow for the development of better methods of diagnosis and avoidance for affected workers and others who may be at risk for future difficulties.

Air Pollutants, Occupational↗
PubMed2000

A randomized, double-blind, placebo-controlled trial of the effect of zafirlukast on upper and lower respiratory responses to cat challenge.

BACKGROUND: Zafirlukast, a leukotriene antagonist, has been shown to have protective effects against a variety of asthma triggers. OBJECTIVE: Our purpose was to evaluate zafirlukast's effects on upper and lower airway responses to cat allergen exposure with use of a well-characterized cat exposure model. METHODS: In a double-blind, placebo-controlled, cross-over trial 18 subjects with cat-induced asthma were randomly assigned to receive 1 week each of zafirlukast or placebo followed by a 1-hour cat challenge. Upper and lower respiratory symptoms were rated and spirometry and acoustic rhinometry were performed. Challenges were stopped early if the subject was too uncomfortable or had a >50% decrease in FEV(1). RESULTS: Overall changes in FEV(1) were significantly different with zafirlukast treatment (P = .02). Significant differences in FEV(1) change were detected at 15 and 30 minutes (P = .027 and .05, respectively) but not at 45 and 60 minutes. Changes in acoustic rhinometry were also significantly different at 15 and 30 minutes (P =.05 and .0005, respectively) but not at 45 and 60 minutes. Challenge length was significantly longer with zafirlukast versus placebo after adjustment for differences in allergen exposure (P = .022). Respiratory symptom scores were significantly different (lower respiratory, P < .001; upper respiratory, P = .038) through the first 30 minutes of the challenge after adjustment for allergen exposure. CONCLUSIONS: Zafirlukast was significantly more effective than placebo in preserving pulmonary function and nasal anatomy and extending challenge length when cat-sensitive asthmatic subjects were exposed to high levels of cat allergen.

Adult↗
PubMed2000

Quantitative IgE antibody assays in allergic diseases.

During the past several years, immunoassays for specific IgE antibodies have been refined to permit reporting results in mass units. Thus quantitative immunoassays for IgE antibodies may be an adjunct to skin tests. In cases of food allergy among children with atopic dermatitis, cutoff values for IgE antibody concentrations to egg, milk, peanut, and fish have been derived to provide 95% positive and 90% negative predictive values. Food-specific IgE antibody determinations can also be used to predict which food allergies are resolving spontaneously. Elevated egg-specific IgE antibody levels in infancy are associated with significantly increased risk for development of inhalant allergies later in childhood. In cases of inhalant allergy, specific IgE antibody levels correlate closely with results of inhalation challenge studies in cat-sensitive persons. Also, mite-specific IgE antibody levels correlate significantly with the mite allergen contents of reservoir dust in the homes of mite-sensitive persons. Immunoassays for quantitation of specific IgE antibodies may be used to document allergen sensitization over time and to evaluate the risk of reaction on allergen exposure. However, immunoassays and skin tests are not entirely interchangeable, and neither will replace the other in appropriate circumstances.

Antibodies, Anti-Idiotypic↗
PubMed2000

Mouse allergen. II. The relationship of mouse allergen exposure to mouse sensitization and asthma morbidity in inner-city children with asthma.

BACKGROUND: Although mouse allergen is known to cause occupational asthma in laboratory workers, its potential significance in home environments has never been studied. OBJECTIVE: This study was designed to define the prevalence of mouse sensitivity and its relationship to mouse allergen exposure and disease activity in inner-city children with asthma. METHODS: A subset of 499 subjects from the National Cooperative Inner-City Asthma Study had dust samples adequate for mouse allergen analysis, as well as valid puncture skin test (PST) results. Data were analyzed to relate mouse allergen exposure and other risk factors to mouse sensitization and asthma morbidity. RESULTS: Eighty-nine (18%) of the 499 children had a positive mouse skin test response. Children whose homes had mouse allergen levels above the median (1.60 microg/g) in the kitchen had a significantly higher rate of mouse sensitization (23% vs 11%, P =. 007). Atopy was also significantly related to mouse sensitization, with 40% of those with more than 4 positive PST responses having mouse sensitivity compared with 4% of those with no other positive PST responses (P <.0001). When atopy and exposure were considered together, 53% of those with more than 4 positive PST responses and allergen levels above the median had a positive PST response to mouse allergen compared with 22% of those with more than 4 positive PST responses and allergen levels below the median (P <.0001). The relationship among mouse allergen exposure, sensitization, and any measures of asthma morbidity was not statistically significant. CONCLUSIONS: Mouse allergen may be an important indoor allergen in inner-city children with asthma, with exposure and atopy contributing to mouse sensitization.

Allergens↗
PubMed2000

Mouse allergen. I. The prevalence of mouse allergen in inner-city homes. The National Cooperative Inner-City Asthma Study.

BACKGROUND: Although mouse allergen is a well-defined cause of IgE-mediated hypersensitivity in occupational settings, it has not been well studied in the general population. OBJECTIVE: We sought to determine the prevalence of mouse allergen in inner-city homes. METHODS: A subset of 608 homes from the National Cooperative Inner-City Asthma Study population had dust samples adequate for analysis of mouse allergen. In addition, data regarding the demographics and housing of the subjects were related to the mouse allergen levels. RESULTS: Ninety-five percent of all homes had detectable mouse allergen (Mus m 1) in at least one room, with the highest levels found in kitchens (kitchen: range, 0-618 microg/g; median, 1.60 microg/g; bedroom: range, 0-294 microg/g; median, 0.52 microg/g; television-living room: range, 0-203 microg/g; median, 0. 57 microg/g). By city, 100% of the kitchens in Baltimore had detectable mouse allergen, with the lowest percentage (74%) in Cleveland. Mouse allergen levels correlated among rooms (R = 0.65-0. 75). Forty-nine percent of the homes had reported problems with mice within the last year, and 29% of the homes had evidence of mice in one or more rooms on home inspection and had higher levels of mouse allergen (P =.0001). Higher allergen levels were also associated with evidence of cockroach infestation in any room (P =.006). None of the other subject or housing demographics evaluated were associated with a higher prevalence or level of mouse allergen. CONCLUSIONS: We conclude that mouse allergen is widely distributed in inner-city homes and that cockroach infestation is associated with high mouse allergen levels.

Allergens↗
PubMed2000

Detection of growth suppression in children during treatment with intranasal beclomethasone dipropionate.

OBJECTIVE: Intranasal beclomethasone dipropionate (BDP) has generally been considered to have no systemic activity at recommended doses, but the potential for long-term effects on growth has not previously been evaluated. This study was undertaken to assess the effects of 1 year of treatment with intranasal BDP on growth in children. STUDY DESIGN: In this double-blind, randomized, parallel-group study, 100 prepubertal children 6 to 9 years old with perennial allergic rhinitis were treated with aqueous BDP 168 microg twice daily (n = 51) or placebo (n = 49) for 1 year. Subjects' baseline heights were required to be between the 5th and 95th percentile, and skeletal age as determined by left wrist radiograph was required to be within 2 years of chronological age. Washout periods for medications known to affect growth, including other forms of corticosteroids, were established, and these medications were prohibited during the study. However, short courses of oral prednisolone lasting no more than 7 days, and short courses of dermatologic corticosteroids lasting no more than 10 days, were allowed. Height was measured with a stadiometer after 1, 2, 4, 6, 8, 10, and 12 months of treatment. The hypothalamic-pituitary-adrenocortical axis was assessed by measurements of 8 AM basal cortisol concentrations and response to. 25 mg cosyntropin stimulation. The primary safety parameter was the rate of change in standing height. Statistical analyses were based on all randomized subjects who received at least 1 dose of medication (intent-to-treat principle). The rate of change in standing height was analyzed for all subjects who entered the study and for those completing the full 12 months of treatment (n = 80). The rate of change in standing height over the 1-year study was calculated as the slope of a linear regression line fitted to each subject's height measurements over time. Because there was a statistically significant between-group difference in standing height at baseline, an analysis of covariance was performed for all analyses of standing height data. RESULTS: Of the 100 subjects enrolled, 90 completed the study. The 2 treatment groups were generally comparable at baseline; however, at baseline, mean age and mean height were significantly greater in the BDP treatment group that the in placebo treatment group. In both analyses, overall growth rate was significantly slower in BDP-treated subjects than placebo-treated subjects. The mean change in standing height after 1 year was 5.0 cm in the BDP-treated subjects compared with 5.9 cm in the placebo-treated subjects. The difference in growth rates was evident as early as the 1-month treatment visit, suggesting that the effect on growth occurred initially. The growth-suppressive effect of BDP remained consistent across all age and gender subgroups, and among subjects with and without a previous history of corticosteroid use. Use of additional exogenous corticosteroids during the study was similar in both groups and did not affect the results. Because there was a baseline imbalance in height, a supplemental analysis of the differences in prestudy growth rates was performed. This analysis found no baseline imbalance in prestudy growth rates. To determine whether the difference in growth rates during the study could be attributed to preexisting growth rates, a z score analysis was performed. The heights of both groups were normalized at baseline and at the end of the study using the US National Center for Health Statistics data for mean and standard deviations of height. This analysis confirmed that the difference in growth rates between the 2 groups was primarily attributable to the treatment rather than to any preexisting difference in growth. Additional analyses confirmed that the results were not influenced by outlier values. No significant between-group difference were found in the hypothalamic-pituitary-adrenocortical axis assessments. No unusual adverse events were observed. (ABSTRACT

Administration, Intranasal↗
PubMed1999

Removal of cockroach allergen from inner-city homes.

BACKGROUND: Allergen avoidance has been shown to improve the morbidity and physiology of asthma. Although cockroach allergen has been implicated in chronic asthma, little work has been reported on the feasibility of allergen removal from infested homes. OBJECTIVE: The objective of this study was to examine the effect of professional pest control and home cleaning on cockroach infestation and allergen concentrations in settled dust samples from the kitchens, bedrooms, and television-living rooms of inner-city homes. METHODS: Thirteen homes in inner-city Baltimore, Maryland, received a professional cleaning, with vacuuming and a thorough cleaning in the kitchen. Pest control technicians applied abamectin 0.05% gel to the kitchen and, to a limited extent, to the rest of the home and the cleaning was repeated. Technicians visited monthly from month 2 to month 8 to inspect, collect dust samples, and place passive cockroach traps. Bla g 1 concentrations in dust extract were measured by means of ELISA. RESULTS: The number of cockroaches captured in passive traps decreased rapidly in 11 homes, but complete extermination was achieved in only 7 homes. Bla g 1 concentrations were reduced by 93% in kitchens, 77% in television-living rooms, and 74% in bedrooms. The relative reduction in cockroach allergen was not related to successful extermination or to signs of poor house-cleaning. CONCLUSION: We concluded that cockroach extermination is feasible in inner-city homes but that standard house-cleaning procedures are only partially effective in removing residual allergen over 8 months.

Allergens↗
PubMed1999

Protamine allergy as a complication of insulin hypersensitivity: A case report.

BACKGROUND: Although most patients receiving insulin produce insulin-specific IgE, significant allergic symptoms develop in very few of them. Patients receiving neutral protamine Hagedorn (NPH) insulin are at increased risk for the development of protamine hypersensitivity. The case of a 19-year-old woman with insulin-dependent diabetes and regular and NPH insulin hypersensitivity is presented. OBJECTIVE: The purpose of this study was to determine whether desensitization to NPH insulin, as well as standard insulin desensitization, could control allergic symptoms in a patient allergic to both NPH and regular insulin. METHODS: The patient required insulin desensitization for severe urticaria, angioedema, and occasional wheezing resulting from her insulin dose. She underwent a standard protocol for insulin desensitization twice in a 2-month period, with persistence in her symptoms. She was found to have high protamine-specific, as well as insulin-specific, IgE levels, and because of her poor response to regular insulin desensitization, she was desensitized to both regular and NPH insulin. RESULTS: Dual desensitization resulted in marked improvement in her symptoms. The patient had recurrence of urticaria and angioedema a year and a half later, at which point the NPH was stopped and she was desensitized to regular insulin. She continued to receive regular insulin 4 times per day over the following 3 years with only occasional hives. CONCLUSION: Patients with insulin allergy may not have complete resolution of their symptoms after standard desensitization, particularly those patients with concomitant protamine allergy. These patients may require protamine/NPH desensitization, an alternative insulin preparation, or both.

Adult↗
PubMed1999

A comparison of skin prick tests, intradermal skin tests, and RASTs in the diagnosis of cat allergy.

BACKGROUND: Skin testing and RASTs are the most commonly used methods for the diagnosis of allergy. Questions remain, however, as to the accuracy of these tests, particularly with regard to the role of intradermal skin tests (IDSTs) in the evaluation of respiratory allergy. OBJECTIVE: The purpose of this study was to determine the predictive value of skin prick tests (SPTs), IDSTs, and RASTs in the diagnosis of cat allergy. METHODS: Patients were challenged with a well-characterized cat exposure model after evaluation by history, SPTs, IDSTs (if SPT results were negative), and RASTs. All patients were evaluated with respect to their upper respiratory responses, although only those patients with asthma were included in the analysis of lower airway responses. Challenge results were considered positive if the mean upper respiratory symptom score was 0.5 or more, the mean lower respiratory symptom score was 0.4 or more, or the maximum fall in FEV1 value was 15% or more. RESULTS: One hundred twenty patients were evaluated. SPT values were positive in 81 patients; of the remaining 39 patients, IDST values were positive in 26 patients. RASTs were performed in 89 patients; the values were positive in 45 of 51 patients with a positive SPT value and were negative in all patients with a negative SPT value. When any positive challenge outcome was considered, positive challenge results were seen in 38 of 41 patients with a positive SPT score, in 10 of 39 patients with a negative SPT score, in 6 of 26 patients with a positive IDST score, in 4 of 13 patients with a negative IDST score, in 27 of 27 patients with a positive RAST score, and in 12 of 44 patients with a negative RAST score. CONCLUSION: Although both SPT and RAST values exhibited excellent efficiency in the diagnosis of cat allergy, IDST scores added little to the diagnostic evaluation.

Adult↗
PubMed1998

Laboratory animal allergy.

Approximately one third of laboratory animal workers have occupational allergy to animal danders, and a third of these have symptomatic asthma. Sensitization generally occurs with the first 3 years of employment, and risk factors include atopic background, as well as job description as it relates to the intensity of exposure. A symptomatic worker can reduce allergen exposure with personal protective devices. A laboratory can further reduce exposure with generally available equipment, such as laminar flow caging, and procedures, such as frequent wet washing of vivaria and careful maintenance of ventilation systems. It is advisable to institute periodic medical screening of all laboratory animal workers with questionnaires and allergy skin testing in addition to providing them with training programs to reduce personal exposure.

Allergens↗