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Biomedical subjects

C S Hosking

Publications and source records attributed to C S Hosking.

At least 19 recordsLinked to original sources

The Melbourne House Dust Mite Study: long-term efficacy of house dust mite reduction strategies.

BACKGROUND: Asthma severity among mite-sensitized individuals appears to be related to the degree of mite allergen exposure. OBJECTIVES: The objective of this study was to assess the long-term effectiveness of mite avoidance measures in the homes of asthmatic children in Melbourne, Australia. METHODS: The concentration of house dust mite allergen (Der p 1) was measured on the child's mattress surfaces and bedroom floors in 85 homes on 10 occasions over a 16-month period. After the first three visits, all mattresses were covered with a semipermeable encasement, and carpeted bedroom floors were randomly allocated to regular applications of a placebo or an "anti-mite" shampoo. RESULTS: The concentration of Der p 1 recovered was initially high in the carpeted bedrooms (n = 66) (41.1, 95% confidence interval, 30.7 to 55.0 microg Der p 1 per gm) and mattresses (n = 85) (39.6, 27.2 to 57.7). During the initial observation period the concentration of mite allergen fell in the treatment, placebo, and parental control groups. During the seven treatment periods, no differences were seen between the Der p 1 concentrations in the groups using the "anti-mite" shampoo, placebo shampoo, or the parental control group (e.g., at visit 4; 12.6, 8.2 to 19.5; 14.8, 8.6 to 25.1; and 12.0, 8.1 to 17.7 microg/gm, respectively). In contrast, the concentration of Der p 1 in samples from uncarpeted floors and mattress encasements was low (4.1, 2.1 to 8.0 microg/gm and 4.2, 2.6 to 6.5 microg/gm, respectively) and insufficient dust for analysis was frequently obtained from these sites. CONCLUSIONS: There was no additional benefit from the use of an "anti-mite" shampoo. The absence of carpets and the use of mattress encasements was a useful long-term strategy for mite allergen avoidance.

Animals

The Melbourne house dust mite study: eliminating house dust mites in the domestic environment.

BACKGROUND: Hypersensitivity to house dust mite allergens is associated with increased asthma morbidity. Asthma severity appears to be related to the degree of mite allergen exposure. Short-term studies suggest that complete avoidance reduces disease severity. OBJECTIVE: The study was designed to assess the effect of different mattress covers and floor coverings on mite allergen concentrations in the homes of mite-sensitive children with asthma in the city of Melbourne, Australia. METHODS: Mite allergen Der p 1 concentration was measured on mattress covers, mattress surfaces, and carpeted and uncarpeted floors in 107 dwellings; and measurement was performed on three occasions over a 5-month period. After the first sampling, all mattress covers and impermeable encasements were permanently removed. RESULTS: The initial geometric mean concentrations of Der p 1 (micrograms per gram of fine dust) from the surfaces of sheepskin, wool, and cotton mattress coverings were greater than those from the surfaces of impermeable mattress encasements (116, 113, and 19 vs 0.4) (p < 0.001); corresponding concentrations on the underlying mattresses were 142, 38, 20, and 0.6, respectively (p < 0.05 to 0.001). At the end of the study these mattress surface concentrations were 79, 65, 9.7, and 3.1, respectively. In 24 dwellings an uncarpeted room was adjacent to a carpeted room. At each visit the concentration of Der p 1 in uncarpeted rooms was below the reported threshold for sensitization and significantly less than that in the adjacent carpeted room. CONCLUSION: In homes of children with asthma, "asthmogenic" concentrations of Der p 1 were found on nonencased mattresses and carpeted floors, but the use of impermeable mattress encasements and carpet exclusion were associated with concentrations of Der p 1 below the reported threshold for sensitization.

Adolescent

Challenge confirmation of late-onset reactions to extensively hydrolyzed formulas in infants with multiple food protein intolerance.

BACKGROUND: Many infants with cow's milk protein intolerance have adverse reactions to soy, casein and whey hydrolysate formula and to other foods. The recent development of Neocate, a hypoallergenic, nutritionally complete infant formula composed of individual amino acids and other nutrients, has enabled these infants to be stabilized. OBJECTIVE: We observed the effect of food challenges in infants with reported hypersensitivity to hypoallergenic formulas. METHODS: Eighteen infants (median age, 7 1/2 months) were given Neocate formula for 2 months and then underwent a 7-day double-blind placebo-controlled challenge with the formula previously best tolerated. RESULTS: In 12 of the 18 infants irritability, vomiting, diarrhea, and/or eczema flares developed during the formula challenge. In two patients symptoms developed immediately, but in the remainder adverse reactions evolved within 7 days (range, 4 to 7 days). Adverse reactions were to soy formula (six patients), whey hydrolysate (two), and casein hydrolysate (four). When infants were 12 months of age, parents reported adverse reactions after the ingestion of other low allergen foods (median, six; from a panel of 10 such foods). CONCLUSION: A group of infants with late-onset adverse reactions to soy, extensively hydrolyzed casein, and whey formulas and to other foods has been identified. Neocate formula proved to be an effective substitute formula for these patients.

Amino Acids

A low allergen diet is a significant intervention in infantile colic: results of a community-based study.

BACKGROUND: The effect of diet change in 38 bottle-fed and 77 breast-fed "colicky" infants, referred from community-based pediatric facilities was studied over a 1-week period in a double-blind (within each feeding mode), randomized, placebo-controlled trial. METHODS: Bottle-fed infants were assigned to either casein hydrolysate or cow's milk formula. All mothers of breast-fed infants were started on an artificial color-free, preservative-free, additive-free diet and also randomized to an active low allergen diet (milk-, egg-, wheat-, nut-free) or a control diet. RESULTS: The response to diet was assessed on day 1 and day 8 with the use of a previously validated infant distress chart on which parents recorded distress levels. If successful outcome was defined as a reduction in distress of 25% or more, after adjusting for age and feeding mode, infants on active diet had a significantly higher rate of improvement than those on the control diet (odds ratio, 2.32; 95% confidence interval, 1.07-5.0; p = 0.03). Analysis of the day 8 to day 1 distress ratio, again adjusted for age and feeding mode, showed that infants on the active diet had distress reduced by 39% (95% confidence interval, 26-50) compared with 16% (95% confidence interval, 0-30) for those on the control diet (p = 0.012). CONCLUSION: The results suggest a period of dietary modification with a low allergen diet and appropriate nutritional support should be considered in healthy infants with colic.

Age Factors

The cow milk allergy complex: overlapping disease profiles in infancy.

Community based studies suggest reported reactions to cow's milk are very common in the first 12 months of life but many of them may not be reproduced on challenge. Recent laboratory based studies have identified three groups of infants with cow milk allergy (CMA) who demonstrate different symptom and laboratory profiles. The first, an IgE-sensitized group, shows features of immediate cutaneous eruptions and anaphylaxis. The second, a non-IgE sensitized group, develops gastrointestinal symptoms within hours of ingesting moderate amounts of cow milk, whereas the third group of patients shows symptoms of gastrointestinal disturbance with or without bronchitic and/or eczematous symptoms after ingesting cow milk over several hours or days. The late reacting non-IgE sensitized CMA patients demonstrate elevated T-cell reactivity in vitro to milk proteins. Hospital based studies, which are likely to reflect the more severe end of the spectrum of CMA, suggest adverse clinical reactions which persist longer may be associated with intolerance to a wide range of foods. Children with persistent CMA frequently develop eczema, asthma and rhinitis. Because of these complexities children with CMA should remain under the long term care of a medical practitioner familiar with the management of these problems. Medical practitioners responsible for the care of children with suspected CMA must be prepared to conduct cow milk challenges in a safe environment with facilities for resuscitation available. The notion that infants with suspected CMA should be referred to nutritionists and health workers for implementation of empirically devised low allergen diet programs without the diagnosis of CMA, being firmly established should be rejected. Where the diagnosis of CMA has not been made with certainty, parents may resort to unreasonable dietary restrictions.

Diagnosis, Differential

A major continuous allergenic epitope of bovine beta-lactoglobulin recognized by human IgE binding.

Hexapeptides of sequential overlapping sequences of beta-lactoglobulin (BLG) were used to probe serum from children with immediate-type cow milk allergy for IgE binding to continuous epitopes of BLG in an enhanced enzyme-linked immunosorbent assay (ELISA). Six regions of IgE binding were identified on the BLG molecule and these were synthesized as dodecapeptides. Inhibition of IgE binding to whole BLG was used to confirm the BLG-specific binding of IgE to each of the synthesized peptides. One of the peptides, peptide 4, showed inhibition in an IgE anti-BLG radioimmunoassay to all 16 sera tested. The patterns of inhibition with the native BLG molecule and peptide 4 were significantly correlated (P = 0.005), suggesting that this peptide contains a major continuous IgE binding epitope of BLG.

Allergens

Cow milk allergy within the spectrum of atopic disorders.

In order to examine the relationship between cow milk allergy (CMA) and atopic disorders in childhood, a consecutive group of 42 infants with IgE mediated CMA was followed for at least 2 years. The incidence of sensitization to common food and inhalant antigens and the development of eczema, asthma, and food allergies was examined for the cohort and compared between patients whose CMA remitted and those with persistent disease. In this cohort the prevalence of eczema was 57%, asthma 69%, egg allergy 67%, peanut allergy 55%, and 83% of infants demonstrated positive skin-prick tests to three or more allergens. At the end of the study CMA had remitted in 13 patients (median age 44 months) whereas in 29 patients it persisted (median age 44 months). Although there was no significant difference in the incidence of eczema or asthma during the study between these two patient groups, the incidence of allergy to egg and peanut butter was significantly greater for children with persistent CMA. Consistent with our hypothesis that children with persistent CMA have a more severe dysregulation of IgE synthesis than those whose disease remits, patients with persistent CMA had a significantly higher incidence of and level of skin sensitivity to inhalant and other dietary allergens. Sensitization to the inhalant allergens Dermatophagoides pteronyssinus, cat dander and rye grass was frequently seen in early infancy and increased during the study period. Thus, children with IgE mediated CMA frequently generate IgE responses to multiple dietary and inhalant allergens in infancy and early childhood and develop immediate hypersensitivity to other foods as well as clinical eczema, and asthma.

Allergens

Lymphocyte production of gamma-interferon as a test for non-tuberculous mycobacterial lymphadenitis in childhood.

Infection with Mycobacterium avium, M. intracellulare and M. scrofulaceum (MAIS) organisms in normal children may result in cervical lymphadenopathy. There is a poor response to anti-tuberculous therapy and surgical excision of infected nodes is necessary. The diagnosis therefore requires consideration in children with cervical lymphadenopathy. A simple in vitro assay is described which may be useful for diagnosis prior to excision. Whole blood is cultured with M. avium purified protein derivative. After 24 h the plasma is removed and the concentration of gamma interferon (IFN-gamma) quantified by a radioimmunometric assay. In a prospective study of 38 children with neck lesions, 16 showed MAIS organisms isolated from cultures of excised tissue. The level of IFN-gamma produced by peripheral blood lymphocytes from children in the MAIS group was significantly greater when compared with children having operations for neck lesions that were not due to MAIS organisms (P < 0.001).

Adolescent

Natural history of cows' milk allergy in children: immunological outcome over 2 years.

In this investigation 98 children (median age 24 months) with cows' milk allergy (CMA) were studied over a median period of 2 years to see whether acquisition of clinical tolerance to cows' milk was associated with the changes in levels of IgG and IgE anti-cows' milk antibodies, and skin test reactivity to a cows' milk extract. Two groups of CMA patients were examined. The first were IgE sensitized and responded rapidly to small volumes of cows' milk with urticaria, and/or exacerbations of eczema, and/or wheeze, and/or vomiting (n = 69). The second, a late reacting group (n = 29) demonstrated coughing, diarrhoea, eczematoid rashes, and/or a combination of these which developed more than 20 hr after commencing normal volumes of cows' milk. Significant immunological changes were confined to the 69 IgE sensitized immediate-reacting-group of patients. Of these, there were 15 children who achieved clinical tolerance to cows' milk and they showed a significant fall in the levels of skin test reactivity to cows' milk over the study period (P < 0.01). In addition, these 15 children had lower serum IgE antibodies to cows' milk proteins both at the outset and the final follow-up compared with the 54 patients whose CMA persisted. No consistent change in the IgG antibody responses to cows' milk proteins was seen in either group of patients over the study period. The findings suggest patients with immediate type hypersensitivity to cows' milk proteins whose disease persists for more than 2 years have a more severe dysregulation of IgE synthesis to cows' milk proteins from the outset.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals

Gamma-interferon production in cow milk allergy.

The aim of this study was to develop an assay to assist in the diagnosis of delayed onset of adverse responses to cow milk in children, by measurement of gamma-interferon (GIFN) produced in vitro in response to beta-lactoglobulin-stimulated blood mononuclear cells. Diagnostic procedures identified 75 children with immediate reactions who had high total IgE and IgE-isotype responses to cow milk, 17 children who developed reactions after 24 h and had low total IgE and low IgE-isotype response to cow milk, and 59 milk-tolerant children. GIFN production was less in children with immediate reactions compared to those with late reactions (P < 0.009), or milk-tolerant children (P = 0.022). The results of this study suggest enhanced T-cell reactivity may be involved in the immuno-pathogenesis of non-immediate cow milk allergy, but GIFN production was not a clinically useful diagnostic test.

Age Factors

Charting infant distress: an aid to defining colic.

The value of a 24-hour distress diary, previously validated against a voice-activated audiotape record, was investigated in 30 infants with colic and 30 control infants. The infants with colic had significantly more distress behavior (300.0 minutes vs 102.5 minutes; p < 0.001), although overlap of duration of distress was noted. On the basis of a clinical definition of colic--total distress lasting 180 minutes in a 24-hour period--the diary had a sensitivity of 77% and a specificity of 87%. The sensitivity of the chart was confirmed in a separate study of another 90 infants with colic.

Child Behavior

Childhood asthma: clinical and immunological changes over a decade.

A group of 26 Australian asthmatic children with laboratory-proven bronchial hyper-reactivity to the allergens of rye grass pollen and/or the house dust mite has been studied over a 9-year period. Clinical symptoms and drug scores were used to evaluate the severity of the patients' asthma and, wherever possible, blood samples were obtained before, during and after the rye grass pollen seasons. The cumulative symptom and drug scores for the 20 patients with bronchial hyper-reactivity to rye grass pollen extract tended to increase during and fall after each pollen season but the peaks were of decreasing amplitude over the 9 years. Since a proportion of these patients underwent hyposensitization to rye grass during year 1, longitudinal comparisons were made between year 2 and year 9. Comparing the individuals at the same three seasonal time-points revealed significantly lower drug scores in year 9 compared with year 2, and in parallel with this, significantly lower total IgE, IgE anti-rye and IgG anti-rye antibodies at all three assessment points. In the 14 patients with bronchial hyper-reactivity to house dust mite the severity of the asthma and the median levels of IgE and IgG mite specific antibodies all decreased over the study period. Despite the progressive improvement in asthma and diminishing immune responses to both rye grass and house mite in the patients, no immunological feature could be identified that correlated significantly with clinical outcome.

Adolescent