ABSTRACT
We report the first experimental studies on the temperature dependence of viscoelastic properties of a room temperature discotic nematic liquid crystal. The splay elastic constant is greater than the bend elastic constant and both show unusual temperature and order parameter dependence. The rotational viscosity is remarkably larger than conventional calamitic liquid crystals. We provide a simple physical explanation based on the columnar short-range order to account for the the unusual temperature dependence of the elastic constants.
ABSTRACT
The effect of heat on the allergenicity of beef and bovine serum albumin was investigated among 10 toddlers skin prick test (SPT)-positive to raw and cooked beef. The meat-allergy diagnosis was confirmed during double-blind, placebo-controlled food challenge (DBPCFC) with 180 g of beef cooked for 5 min at 100 degrees C. SPT with homogenized and freeze-dried beef, and heated and unheated bovine serum albumin were performed. Both heated and unheated bovine serum albumin, homogenized beef, and freeze-dried beef were used in trial DBPCFC. All children were SPT-positive to unheated bovine serum albumin. Seven were positive to heated bovine serum albumin, one to freeze-dried beef, and none to homogenized beef. DBPCFCs were negative for homogenized beef and freeze-dried beef, positive for unheated bovine serum albumin in five patients, and positive for heated albumin in four children. We conclude that heating reduces sensitization to beef and bovine serum albumin but does not abolish reactivity to albumin under home conditions. However, industrially heat-treated and sterilized homogenized beef and freeze-dried beef may be suitable substitutes in beef-allergic children's diets.
Subject(s)
Allergens , Food Hypersensitivity/prevention & control , Hot Temperature , Meat/adverse effects , Serum Albumin, Bovine/immunology , Animals , Cattle , Child, Preschool , Cooking , Densitometry , Electrophoresis, Polyacrylamide Gel , Freeze Drying , Humans , Regression Analysis , Skin Tests , Statistics, NonparametricABSTRACT
BACKGROUND AND OBJECTIVES: Although cromones inhibit immediate bronchial responses to both allergen and nonspecific challenge, their effectiveness in treating nonatopic childhood asthma is unknown. We therefore investigated a possible effect of nedocromil sodium on bronchial hyperreactivity and asthmatic symptoms in a group of children receiving this drug for nonatopic asthma. STUDY DESIGN AND METHODS: A double-blind, placebo-controlled, randomized trial of two parallel groups was carried out in our pediatric respiratory disease clinic. Twenty children with mild, nonatopic asthma hyperreactive to fog-induced challenge were treated with inhaled nedocromil sodium 16 mg each day for 6 weeks (group N) or with a placebo (group P). Five girls and five boys (7 to 13 years of age) were randomly assigned to group N, and three girls and seven boys (aged 6 to 16 years) to group P. Symptoms and bronchodilator use were reported on diary cards. Ultrasonic nebulized distilled water PD10 was measured administering increasing doses of nebulized distilled water (2.5, 5, 10, 20, and 40 L). RESULTS: Symptom scores were significantly affected by the active treatment. Baseline lung function was normal and remained unaltered after treatment with nedocromil sodium. Nonspecific reactivity was significantly reduced over time only in the active treatment group. CONCLUSIONS: Nedocromil sodium can reduce the severity of asthmatic symptoms and nonspecific bronchial hyperreactivity at fog-induced challenge in children with stable, nonatopic asthma.
