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Biomedical subjects

S A Bock

Publications and source records attributed to S A Bock.

At least 37 records · Page 2Linked to original sources
PubMed1990

Patterns of food hypersensitivity during sixteen years of double-blind, placebo-controlled food challenges.

For 16 years the double-blind, placebo-controlled food challenge (DBPCFC) has been used at the National Jewish Center for Immunology and Respiratory Medicine to determine whether adverse reactions to foods do occur in children. The objective of these studies was to explore these reproducible adverse reactions and to characterize them. Although skin testing was performed on all subjects, a history of an adverse reaction to food and to subsequent DBPCFC were the only criteria for entry into this study. Of 480 children studied, 185 (39%) have had positive DBPCFC results. In these 480 children, 245 (24%) of 1014 DBPCFCs showed positive results. Egg, peanut, and cow milk accounted for 73% of the positive DBPCFC reactions, but many foods produced reactions. Skin test results were positive in most children with a positive DBPCFC reaction, but the large number of patients with asymptomatic hypersensitivity limited the accuracy of a positive skin test result alone as a predictor of clinical symptoms during food ingestion. Evaluation of results in this large number of children for a prolonged period revealed reproducible patterns of symptoms, timing, and incriminated foods. Placebo reactions were rare. The procedure was safe. Twelve youngsters with a negative DBPCFC result subsequently had positive reactions to open challenges when large amounts of the challenge food were used. In each of these cases the reactions were limited to areas of direct contact with the food or could be explained by the larger amount of food ingested during the open challenge. Multiple food hypersensitivity has been a rare finding. The DBPCFC should be the "gold standard" for both research and clinical diagnostic evaluations until it is superseded by methods that have yet to be developed.

Adolescent↗
PubMed1989

The natural history of peanut allergy.

Between 1973 and 1985, 114 children, aged 2 to 14 years, underwent double-blind, placebo-controlled, food challenge (DBPCFC) to peanut. Thirty-two of 46 children with symptoms produced by DBPCFC to peanut were included in this longitudinal evaluation. Contact was made with the 32 subjects 2 to 14 years after their positive DBPCFC to peanut. All 32 subjects had exhibited a positive puncture skin test to peanut at the time of the original evaluation. Sixteen subjects had experienced symptoms caused by accidental peanut ingestion in the year before contact. Eight subjects had reacted to accidental ingestion in more than 1 year but less than 5 years before contact. Eight subjects had completely avoided peanut since the original evaluation and positive DBPCFC. No subjects could be demonstrated to have "outgrown" their peanut reactivity. All subjects tested continued to have skin reactivity to a puncture skin test with peanut extract. It appears uncommon for peanut-sensitive patients to lose their clinical reactivity, even after many years have elapsed. In addition, data were collected concerning reactions to other legumes and other (nonlegume) nuts. Only two patients with DBPCFC to peanut reacted on DBPCFC to soy or pea (one each). None of the subjects with a positive DBPCFC to peanut reacted to nonlegume nuts.

Adolescent↗
PubMed1988

Double-blind, placebo-controlled food challenge (DBPCFC) as an office procedure: a manual.

There is now enough experience with the use of double-blind, placebo-controlled, food challenge (DBPCFC) to recommend its use as an office procedure for most patients complaining of adverse reactions to foods. This manual discusses the practical methods required for the allergist to undertake DBPCFC in the office. Thorough histories supplemented by food allergen skin testing are used to design a DBPCFC that carefully attempts to reproduce the history of food-induced symptoms described by the patient. Precautions that must be taken are delineated before challenge, as is treatment that may be required if a reaction occurs. For those foods to which challenges are positive, longitudinal evaluation with repeated challenge at appropriate intervals help to determine whether or not the problem will resolve over a period of time.

Allergens↗
PubMed1988

Cottonseed hypersensitivity: new concerns over an old problem.

Seven subjects, who experienced systemic allergic reactions after the ingestion of a newly marketed food supplement, were evaluated to identify the responsible ingredient. Skin testing with extracts prepared from ingredients in the food supplements revealed marked sensitization of all of the subjects to cottonseed protein. Double-blind, placebo-controlled food challenges performed in two subjects with cottonseed flour produced reactions consisting of oropharyngeal pruritus, rhinitis, nausea, diaphoresis, dyspnea, cough, and a fall in pulmonary function tests of 45% or more. All placebo challenges were negative. Because of the reactions observed during these challenges, other subjects were not challenged orally with cottonseed protein but consumed without incident other ingredients in the supplement to which they were skin test positive. Our evaluation strongly incriminates cottonseed protein as the cause of the systemic allergic reactions in these subjects and is consistent with earlier articles in the literature describing the potent allergenicity of cottonseed protein.

Adolescent↗
PubMed1987

Prospective appraisal of complaints of adverse reactions to foods in children during the first 3 years of life.

To examine the natural history of adverse reactions to foods, 480 children were followed prospectively from birth to their third birthdays. Foods thought to be causing symptoms were evaluated by elimination of suspected foods, open challenges, and double-blind food challenges. Foods producing symptoms were reintroduced into the diet at 1- to 3-month intervals until the symptoms no longer occurred. Of the 480 children completing the study, 28% were thought to have symptoms produced during food ingestion, but in only 8% were these reactions reproduced (excluding fruit and fruit juices). During the first year of life 80% of the initial complaints occurred. The most striking finding was the brief duration during which reactions could be reproduced. The majority of foods were replaced in the diet within 9 months of their incrimination. A long list of foods was reported to produce many symptoms, but only a few foods reproducibly evoked gastrointestinal and skin symptoms, with respiratory symptoms being infrequent. Of great interest was that 75 children were reported to react to fruit or fruit juice, and 56 of these children had reproducible symptoms. This study has found that most food reactions occur during the first year of life, but rechallenge at regular intervals has shown that the food can be reintroduced into the diet by the third year without risk. Almost all reactions that were reproduced appear to be non-immunoglobulin E mediated.

Animals↗
PubMed1985

Natural history of severe reactions to foods in young children.

Nine children with very severe adverse reactions to foods during the first 2 years of life were followed to determine the subsequent course of their reactions. Cautious challenges were given in these children over a period of time. Three of nine children can tolerate the offending food in usual portions; four of nine can tolerate small amounts of the offending food; and two children continue to have reactions to small amounts of the offending food. At some time each of these children have exhibited significant positive wheal and flare reactions when skin tested with extracts of the offending food. This study demonstrates that some children with severe reactions to foods may lose their frightening reactivity to foods over time. Very careful challenges in these patients are thus justified to save families from prolonged anxiety about accidental ingestion, which inevitably occurs.

Animals↗
PubMed1984

Chronic sclerosing tracheobronchitis.

We report a child with wheezing and respiratory distress of 53 months duration which was undiagnosed and unresponsive to treatment. Necropsy examination of trachea and bronchi showed narrowing by chronic inflammation and fibrosis of mucosa and submucosa. Despite intensive investigations, the aetiology and pathogenesis remained undetermined.

Bronchi↗
PubMed1984

Anaphylaxis presumed to be caused by beef containing streptomycin.

Most adverse reactions to foods have been blamed on proteins derived from the ingested substance. Reports in the literature document that adverse reactions to foods can be caused by contaminants. The youngster reported here had anaphylaxis on four occasions, likely caused by the presence of streptomycin.

Adolescent↗
PubMed1984

Serum complement changes during double-blind food challenges in children with a history of food sensitivity.

Serum levels of C3, C4, factor B, properdin, total hemolytic complement and alternative-pathway hemolytic activity were measured before and after double-blind food challenge in 23 children with impressive histories of adverse reactions to foods. The 23 subjects had 11 positive food challenges and 12 negative food challenges. Nine patients with reagin-mediated positive food challenges showed increases in all six complement assays after double-blind food challenge, while the group with negative food challenges showed decreases in five of the six assays. The difference between the two groups for complement changes after double-blind food challenge was significant only for the alternative-pathway assay. Individual subject analysis revealed markedly heterogeneous changes in direction and magnitude within both groups for all complement assays. Therefore, it is concluded that measurement of serum complement levels is not a useful test for the clinical evaluation of a patient with suspected food sensitivity.

Adolescent↗
PubMed1983

Immunochemical localization of proteins in the intestinal mucosa of children with diarrhea.

Chronic diarrhea in children is a common and often frustrating problem confronting allergists, pediatricians, and gastroenterologists. We know very little about the mechanism and immunology of this problem. This study used an immunoperoxidase staining technique to evaluate the small bowel biopsy specimens of 15 children with chronic diarrhea. Ten children had diarrhea related to a specific food ingestion, and five had prolonged diarrhea without identification of an offending food. The new finding was the deposition of stain beneath the mucosal cells in the area of the basement membrane of the small bowel mucosa. Anti-IgG and anti-bovine serum albumin (BSA) were the antibody reagents most often associated with the detection of tissue deposits. Deposits of stain were found when the inflammatory system was active as determined by the presence of increased numbers of inflammatory walls in the mucosa.

Animals↗