Provocation Procedure Research Articles

Offset control during recurrent 20% carbon dioxide-enriched air induction: relation to individual difference variables.

Although control over aversive events maintains a central role in contemporary models of anxiety pathology, particularly panic disorder, there is little understanding about the emotional consequences of specific types of control processes. In the present study, offset control over 8 20% carbon dioxide-enriched air administrations was experimentally manipulated in a large nonclinical population (n = 96) varying in anxiety sensitivity (high or low) and gender. Dependent measures included self-reported anxiety, affective reports of valence, arousal, emotional control, and physiological indices of heart rate and skin conductance. High anxiety-sensitive participants who lacked offset control reported significantly greater elevations in self-reported anxiety, emotional displeasure, arousal, and dyscontrol relative to their yoked counterparts with offset control. In contrast, low anxiety-sensitive individuals responded with similar levels of cognitive and affective distress regardless of the offset control manipulation. Although the provocation procedure reliably produced bodily arousal relative to baseline, at a physiological level of analysis, no significant differences emerged across conditions. These findings are discussed in relation to offset control during recurrent interoceptive arousal, with implications for better understanding anxiety about abrupt bodily sensations.

Airborne and dietary allergens in atopic eczema: a comprehensive review of diagnostic tests.

Aeroallergens and food allergens are relevant eliciting factors of atopic eczema. This article focuses on the methods used for diagnosis in patients with suspected allergy to airborne or dietary allergens and who are suffering from atopic eczema. In addition to classical tests of IgE-mediated hypersensitivity (intracutaneous or in vitro testing), the role of provocation procedures is described. For aeroallergens, the atopy patch test yields the most specific results with regard to clinical history as compared with classical methods. For food allergens and pseudoallergic reactions to additives, this holds true for the double-blind, placebo-controlled food challenge. The methods and their limitations are discussed from a practical point of view.

Reliability of physical examination of the upper extremity among keyboard operators

Background Physical examination is a traditional outcome measure in epidemiological research. Its value as a reliable measure depends, in part, on the prevalence of positive findings. The purpose of this paper is to determine the empirical reliability of physical examination and anthropometry in a field study of upper extremity disorders among keyboard operators. Methods Two experienced examiners independently performed common provocative tests and procedures in physical examinations of the neck and upper extremity among 160 keyboard operators. Two additional examiners conducted anthropometric surveys among 137 workers. Inter-examiner reliability was assessed with observed agreement, kappa statistics, and intra-class correlations (ICC). Results Observed agreement was between 96% and 100% for neck and upper extremity signs, muscle stretch reflexes, and muscle strength, however, with the exception of provocative tests, reliability statistics were unstable. Among the provocative tests, Phalen and Tinel tests had modest agreement after adjusting for chance (κ range: 0.20–0.43). The carpal compression test had the best reliability (κ=0.60 and κ=0.67, left and right side, respectively). The ICCs for anthropometry ranged from 0.36–0.91. Conclusions Results from the study showed that statistically, except for the carpal compression test, physical examination contributed minimal reliable information. This was attributed mainly to the low prevalence of positive findings, and generally mild nature of upper extremity disorders in this population. The results are the best estimate of what would be found in a field study with experienced examiners. While it may reduce bias, separating physical examination from medical history may contribute to the poor reliability of findings. With a shift toward reliable measures, resources can be allocated to more effective tools, like questionnaires, in epidemiological research of upper extremity disorders among keyboard operators. Am. J. Ind. Med. 37:423–430, 2000. © 2000 Wiley-Liss, Inc.

Reliability of physical examination of the upper extremity among keyboard operators.

Physical examination is a traditional outcome measure in epidemiological research. Its value as a reliable measure depends, in part, on the prevalence of positive findings. The purpose of this paper is to determine the empirical reliability of physical examination and anthropometry in a field study of upper extremity disorders among keyboard operators. Two experienced examiners independently performed common provocative tests and procedures in physical examinations of the neck and upper extremity among 160 keyboard operators. Two additional examiners conducted anthropometric surveys among 137 workers. Inter-examiner reliability was assessed with observed agreement, kappa statistics, and intra-class correlations (ICC). Observed agreement was between 96% and 100% for neck and upper extremity signs, muscle stretch reflexes, and muscle strength, however, with the exception of provocative tests, reliability statistics were unstable. Among the provocative tests, Phalen and Tinel tests had modest agreement after adjusting for chance (kappa range: 0.20-0.43). The carpal compression test had the best reliability (kappa=0.60 and kappa=0.67, left and right side, respectively). The ICCs for anthropometry ranged from 0.36-0.91. Results from the study showed that statistically, except for the carpal compression test, physical examination contributed minimal reliable information. This was attributed mainly to the low prevalence of positive findings, and generally mild nature of upper extremity disorders in this population. The results are the best estimate of what would be found in a field study with experienced examiners. While it may reduce bias, separating physical examination from medical history may contribute to the poor reliability of findings. With a shift toward reliable measures, resources can be allocated to more effective tools, like questionnaires, in epidemiological research of upper extremity disorders among keyboard operators.

Maximizing Efficacy of Endocrine Tests: Importance of Decision-focused Testing Strategies and Appropriate Patient Preparation

The efficacy of endocrine tests depends on the choice of tests, the preparation of the patients, the integrity of the specimens, the quality of the measurements, and the validity of the reference data. Close dialogue among the clinicians, the laboratory, and the patients is a key factor for optimal patient care. The characteristics of urine and plasma samples and the advantages and limitations of paired test measurements are presented. The importance of test sequence strategies, provocative or inhibitory procedures, and elimination of drug interferences is illustrated with four cases involving Cushing syndrome, pheochromocytoma, primary aldosteronism, and hypercalcemia. For each of these scenarios, key clinical issues are highlighted, along with discussions of the best test strategies, including which medications are likely to interfere. The importance of targeting laboratory tests to answer well-focused clinical decisions is emphasized. The roles of some time-honored provocative procedures are questioned in light of more sensitive and specific analytic methods. The importance of decision-focused analytical tolerance limits is emphasized by demonstrating the impact of analytic bias on downstream medical resource utilization. User-friendly support systems to facilitate the implementation of test strategies and postanalytic tracking of patient outcomes are presented as essential requirements for quality medical practice.

Histamine provocation in young, awake children with bronchial asthma, using a fall in oxygenation as the only indicator of a bronchial reaction

Bronchial provocation with histamine was performed in 11 boys and 6 girls, age range 2.7‐7.4 y, with unspecific respiratory symptoms or bronchial asthma, using a fall in oxygenation as the only indicator of a bronchial reaction. In addition to transcutaneous oxygen tension (tcPO2), transcutaneous carbon dioxide tension (tcPCO2) was continuously monitored during the provocation procedure in order to identify possible changes in ventilation. A fall of 20% or more in the tcPO2 below a “floating” baseline value, defined as the highest tcPO2 value between the inhalations of histamine up to that point, was regarded as indicating a significant bronchial reaction. One child was excluded from the study because of an “early, false‐positive” reaction due to hyperventilation during the inhalation, verified by a decrease in the tcPCO2 followed by a compensatory period of hypoventilation, resulting in a fall of more than 15% in the tcPO2 after the inhalation of saline. In the vast majority of the children, however, the tcPO2 values remained stable during the first dose stages of saline and histamine, with either a gradual fall immediately before or a distinct fall in conjunction with the reaction. The mean reaction concentration was significantly lower in the group of children with clinical asthma, 0.74 mg/ml, compared with the group of children with unspecific respiratory symptoms, 2.00 mg/ml (p = 0.03). In conclusion, a 20% fall in the tcPO2 can be used as the only indicator of a bronchial reaction during bronchial provocation tests in young, awake children. Changes in ventilation evaluated by monitoring tcPCO2, makes it possible to distinguish between a fall in oxygen tension due to an early, “false” reaction as a result of hypoventilation and a “true” bronchial reaction. □Asthma, bronchial provocation, oxygenation, young children

Histamine provocation in young, awake children with bronchial asthma, using a fall in oxygenation as the only indicator of a bronchial reaction.

Bronchial provocation with histamine was performed in 11 boys and 6 girls, age range 2.7-7.4 y, with unspecific respiratory symptoms or bronchial asthma, using a fall in oxygenation as the only indicator of a bronchial reaction. In addition to transcutaneous oxygen tension (tcPO2), transcutaneous carbon dioxide tension (tcPCO2) was continuously monitored during the provocation procedure in order to identify possible changes in ventilation. A fall of 20% or more in the tcPO2 below a "floating" baseline value, defined as the highest tcPO2 value between the inhalations of histamine up to that point, was regarded as indicating a significant bronchial reaction. One child was excluded from the study because of an "early, false-positive" reaction due to hyperventilation during the inhalation, verified by a decrease in the tcPCO2 followed by a compensatory period of hypoventilation, resulting in a fall of more than 15% in the tcPO2 after the inhalation of saline. In the vast majority of the children, however, the tcPO2 values remained stable during the first dose stages of saline and histamine, with either a gradual fall immediately before or a distinct fall in conjunction with the reaction. The mean reaction concentration was significantly lower in the group of children with clinical asthma, 0.74 mg/ml, compared with the group of children with unspecific respiratory symptoms, 2.00 mg/ml (p = 0.03). In conclusion, a 20% fall in the tcPO2 can be used as the only indicator of a bronchial reaction during bronchial provocation tests in young, awake children. Changes in ventilation evaluated by monitoring tcPCO2, makes it possible to distinguish between a fall in oxygen tension due to an early, "false" reaction as a result of hypoventilation and a "true" bronchial reaction.

Panic provocation procedures in the treatment of panic disorder: Early perspectives and case studies

Although panic provocation procedures have been utilized for many decades to generate and test hypotheses about the pathophysiology of panic disorder, very little is known about the value of these procedures for treatment. In this article, we discuss the theoretical and practical issues related to panic provocation procedures in the treatment of panic disorder. We conclude that hyperventilation, physical exercise, and other activities that induce paniclike symptoms are among the most suitable provocation procedures for use in treatment. Two cases illustrate the use of such procedures in cognitive-behavioral intervention.

Diagnostic methodology in food allergy

Summary The diagnostic tools for the assessment of food allergy in children still lacks reliable in vitro tests that could both ascertain the actuality of food allergy and predict with a good accuracy which allergens may be involved. Skin prick tests or RASTs are an appropriate first step if an IgE-mediated reaction is suspected. Their interpretation has to be considered according to the age of the child. They can also partially indicate the possible outcome of the disease. More sophisticated tests evaluating a cellular response have not proven valid or are still under evaluation, such as the TNF alpha release by mononuclear cells under stimulation with cow's milk protein in cow's milk protein allergic children. The diagnosis requires food elimination diets, followed by provocation procedures, ideally in a double blind placebo controlled fashion. Intestinal permeability tests usefully complement the search for the offending food by providing a non invasive evaluation of small intestinal suffering.

Predictive value of oral sulfonamide challenge for adverse reactions.

Predictive value of oral sulfonamide challenge for adverse reactions.

Validation of the latex glove provocation procedure in latex-allergic subjects.

A latex provocation test is needed to clarify the allergic status of patients who present with a positive clinical history for latex allergy and a negative latex skin test and/or serologic test. In the present study, we aimed to optimize and validate the performance and safety of a latex glove provocation protocol and to employ it to verify the barrier properties of the Dermapor expanded polytetrafluorethylene (ePTFE) glove liner (liner) for latex glove allergen. Twenty-one skin test positive latex-allergic subjects donned goggles and a silicone mask, washed their hands and then put high allergen-containing latex gloves (mean = 15,072 AU/mL) on a moist, bare and liner-covered hand. Due to an absence of verifiable reactions on the bare hand in the first five subjects, the protocol was modified to puncture the skin in three sites on the hand prior to donning the liner/glove or latex glove alone. Subjects were observed for 30 minutes for localized allergic symptoms (pruritus and hives). Lined and unlined hands were compared for reactions. Application of highly allergenic latex gloves onto the bare hands of five skin test-positive, latex-allergic subjects produced some mild pruritus but no visually detectable dermatitis. In contrast, all 17 latex-allergic subjects who underwent the modified glove challenge protocol involving a puncture prior to glove application experienced intense pruritus with measurable wheals and erythema at sites where their skin was punctured. Equivalent wheal and erythema reactions were observed at a site where a puncture was performed directly through the glove. These same subjects experienced no pruritus or hives on their opposite hands that received a liner prior to latex glove application. Direct application of highly allergenic latex gloves onto the hands of skin test-positive, latex-allergic individuals does not commonly produce localized allergic symptoms after minutes, especially if the subject has successfully avoided latex and has no evidence of dermatitis. By puncturing the skin prior to latex glove donning, quantifiable hives are produced within 15 minutes following glove application. A Dermapor ePTFE liner prevents the transfer of allergen from gloves onto the skin and therefore can serve to minimize contact exposure as part of avoidance therapy.

Alcohol effects on the facial expressions of anxiety patients undergoing a panic provocation

Using subjects with panic disorder, we investigated the effect of alcohol on expressive-emotional facial reactions to a well-known laboratory panic provocation procedure (inhalation of 35% carbon dioxide). Subjects consuming alcohol (vs. a placebo) displayed lower levels of emotional masking and fear/distress facial responses; however, differences were significant only for emotional masking. A composite variable combining the masking and fear/distress scores was also significantly lower in the group consuming alcohol. To the extent that masking behavior is a valid proxy for fear/distress responding, then the latter finding supports the conclusion that alcohol reduced negative affectivity associated with the inhalation. However, we also note the possibility that alcohol reduced masking directly without affecting fear/distress. We make parallel recommendations for future research that treats masking behavior as a nuisance variable on the one hand, or a dependent variable of potential importance on the other. We conclude that expressive-behavioral measures appear to be both feasible and potentially informative in alcohol research.

Allergy to nondairy proteins in mother's milk as assessed by intestinal permeability tests

The intestinal permeability test is a noninvasive method which, when done during a food provocation procedure, can detect the deleterious effect of food on the intestinal mucosa in allergic children. We report on a 1-month-old breast-fed boy with a history of regurgitation, diarrhea, difficult feeding, and malaise suggesting food allergy. Intestinal permeability tests were done with the mother's milk and showed breast-milk-induced alterations of intestinal permeability. No improvement occurred in the child's clinical symptoms or in the results of the intestinal permeability test when the mother withdrew dairy products from her diet. Disappearance of the child's symptoms and normalization of intestinal permeability during provocation with the milk were obtained after elimination of egg and pork from the mother's diet. This observation suggests that dietary proteins different from cow's milk antigens may be transferred to breast milk and induce adverse reactions in hypersensitive infants.

Influence of sensitization and allergen provocation procedures on the development of allergen-induced bronchial hyperreactivity in conscious, unrestrained guinea-pigs

The effects of different sensitization and allergen provocation regimens on the development of allergen-induced bronchial hyperreactivity (BHR) to histamine were investigated in conscious, unrestrained guinea-pigs. Similar early and late phase asthmatic reactions, BHR for inhaled histamine after the early (6 h) as well as after the late reaction (24 h), and airway inflammation were observed after a single allergen provocation in animals sensitized to produce mainly IgG or IgE antibodies, respectively. Repeating the allergen provocation in the IgE-sensitized animals after 7 days, using identical provocation conditions, resulted in a similar development of BHR to histamine inhalation. Repetition of the allergen provocation during 4 subsequent days resulted in a decreased development of BHR after each provocation, despite a significant increase in the allergen provocation dose necessary to obtain similar airway obstruction. The number of inflammatory cells in the bronchoalveolar lavage was not significantly changed after repeated provocation, when compared with a single allergen provocation. Finally, we investigated allergen-induced bronchial hyperreactivity by repetition of the sensitization procedure at day 7 and 14 (booster), followed by repeated allergen provocation twice a week for 5 weeks. Surprisingly, no BHR to histamine could be observed after either provocation, while the number of inflammatory cells in the bronchoalveolar lavage fluid after 5 weeks was enhanced compared with controls. These data indicate that both IgE and IgG sensitized guinea-pigs may develop bronchial hyperreactivity after a single allergen provocation. Repeated allergen exposure of IgE sensitized animals causes a gradual fading of the induced hyperreactivity despite the on-going presence of inflammatory cells in the airways, indicating a mechanism of reduced cellular activation.

Allergy to nondairy proteins in mother's milk as assessed by intestinal permeability tests

The intestinal permeability test is a noninvasive method which, when done during a food provocation procedure, can detect the deleterious effect of food on the intestinal mucosa in allergic children. We report on a 1-month-old breast-fed boy with a history of regurgitation, diarrhea, difficult feeding, and malaise suggesting food allergy. Intestinal permeability tests were done with the mother's milk and showed breast-milk-induced alterations of intestinal permeability. No improvement occurred in the child's clinical symptoms or in the results of the intestinal permeability test when the mother withdrew dairy products from her diet. Disappearance of the child's symptoms and normalization of intestinal permeability during provocation with the milk were obtained after elimination of egg and pork from the mother's diet. This observation suggests that dietary proteins different from cow's milk antigens may be transferred to breast milk and induce adverse reactions in hypersensitive infants.

Agoraphobic avoidance and panic frequency as predictors of laboratory induced panic reactions

This study examined the importance of agoraphobic avoidance and frequency of panic as predictors of psychological and physiological responses of panic sufferers to a laboratory based provocation procedure. Psychophysiologic comparisons were made between 22 panic disorder patients and 15 controls, at baseline and across three periods of carbon dioxide gas inhalations (1, 3, 5%; balance oxygen). Subjective measures of anxiety, frightening cognitions and body sensations were obtained across the phases. Physiological measures of minute ventilation, breathing rate, tidal volume, end tidal CO 2 and heart rate were also obtained. Between group comparisons revealed significant differences between the groups on the subjective measures with no significant differences occurring on the physiological measures. Within group analyses revealed that pre-session questionnaire measures of agoraphobia avoidance and panic frequency predicted the degree of anxiety, frightening sensations and cognitions during baseline and 5% CO 2 inhalation. The results indicated that both self-reported agoraphobic avoidance and panic frequency are strong clinical predictors of psychological reactions of panic sufferers during laboratory provocation.

Lebensmittelallergien und -intoleranzreaktionen

Adverse reactions to food and food additives are defined by its different pathomechanisms. Clinically most important are allergic (immunologic) reactions (types I and III), which occur in 7-10% of the general population, and nonimmunologic (pseudoallergic) reactions (PAR), which occur in 1-2%, besides nonallergic reactions by vasoactive amines. Clinical features are equal. Sources of antigens for allergic reactions are proteins of cow's milk, fish, hen's egg, meat, and all kinds of cereals, fruits, vegetables, and spices, while pseudoallergic reactions are induced by chemicals (preservatives, colorants, antioxidants). The diagnostic procedures of allergic reactions include the proof of sensitization by case history, skin test, specific IgE (and IgG) in-vitro, elimination diet and provocation test; pseudoallergic reactions with no underlying sensitization are diagnosed only by elimination and provocation procedures.

Testing the Hypoallergenicity of a Formula Measuring Intestinal Permeability During Provocation Procedures

Testing the Hypoallergenicity of a Formula Measuring Intestinal Permeability During Provocation Procedures

Testing the Hypoallergenicity of a Formula Measuring Intestinal Permeability During Provocation Procedures

Testing the Hypoallergenicity of a Formula Measuring Intestinal Permeability During Provocation Procedures

The effects of voluntary hyperventilation on patients with chest pain without coronary artery disease

The present investigation was designed to examine panic symptom experience in patients with chest pain of nonorganic etiology, using a hyperventilation provocation procedure. Given the recent focus on panic disorder in patients with nonorganic chest pain, we assessed three indices of physiological arousal, subjective anxiety, and endorsement of DSM-III-R panic symptomatology in response to 3 min of voluntary hyperventilation. Subjects included 23 patients with nonorganic chest pain (CP sample) and matched normal controls (NC sample). The results indicate that hyperventilation produced significant increases in skin conductance, heart rate, and upper trapezious EMG in both CP and NC samples. Despite equivalent levels of physiological arousal and subjective anxiety, the CP sample endorsed a greater number of DSM-III-R panic symptoms relative to the NC sample. Examination of post-hyperventilation symptoms indicated that a greater percentage of the CP sample reported palpitations, nausea, and chest pain when compared with normals. Comparison of CP patients with and without Panic Disorder revealed no significant differences on any measure. The results suggests that hyperventilation plays a role in symptom experience in patients with nonorganic chest pain, although anxiety does not appear central in moderating this effect.