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Biomedical subjects

H S Nelson

Publications and source records attributed to H S Nelson.

At least 127 records · Page 7Linked to original sources

Cross allergenicity among grasses determined by tissue threshold changes.

Twenty-seven volunteers with grass-pollen allergy who had not received prior immunotherapy had titrated prick tests with fivefold dilutions of 10 grasses (timothy, Bermuda, smooth brome, grama, salt, quack, western wheat, Johnson, June, and Bahia) to a final dilution of 1:3,906,250 w/v. Ten subjects served as untreated control subjects. Seventeen subjects received immunotherapy with an extract containing equal parts of timothy and Bermuda. Twelve months later subjects had repeat titrated skin testing with reconstituted aliquots of the same lyophilized extract, at the same time of day, and at the same location on the back as in the initial testing period. Nine treated subjects and eight control subjects completed the study protocol. The skin test areas with all 10 grass extracts were significantly decreased in the treated group compared to the control group (p less than 0.01), and there was no difference in the extent of the reduction among the 10 grasses by analysis of variance. We conclude that immunotherapy to timothy and Bermuda alone is capable of reducing to a similar degree the clinical sensitivity to all 10 grasses studied. The results of this study suggest that treatment with timothy and Bermuda alone may be sufficient in most grass-sensitive individuals.

Allergens↗

An investigation of possible immunologic reactions to human serum albumin used as a stabilizer in allergy extracts.

Two hundred fifteen patients who had received allergy immunotherapy for at least 1 year with an extract preparation containing 0.03% human serum albumin (HSA) were tested for evidence of an immunologic reaction to HSA by immediate skin testing. Sera from 39 of these subjects and from control subjects were studied in a microtiter enzyme-linked immunosorbent assay for anti-HSA antibodies. The 39 subjects' sera were examined by immunoelectrophoretic analysis for evidence of "tailing albumin" indicative of HSA bound to immunoglobulins. All studies were negative. We conclude that in these patients HSA-containing allergy extracts used in immunotherapy failed to induce the production of specific antibodies against HSA. This suggests that HSA was a safe extract stabilizing agent for allergy extracts in these representative allergic patients.

Allergens↗

Cromolyn sodium in seasonal allergic conjunctivitis.

A formulation of 2% cromolyn sodium (CS) ophthalmic solution without the preservative, 2-phenylethanol, was compared with placebo in 58 patients with seasonal allergic conjunctivitis. Selection was based on history and positive skin tests. Neither immunotherapy nor use of antihistamines was allowed. This study was double-blinded and stratified by RAST scores to assure comparable groups. Either CS or placebo was used six times daily. Patients were observed weekly for 5 weeks during the peak of the fall weed-pollen exposure. Nasal symptoms were treated as required with beclomethasone nasal spray, and uncontrolled ocular symptoms were treated with boric acid and ephedrine solution. Nasal and ocular symptoms were recorded. There was a significant suppression of eye symptoms in the group receiving CS ophthalmic solution (p less than 0.02) during weeks 2, 4, and 5. There was a trend for nasal symptoms and the requirement for nasal beclomethasone to be less in patients receiving CS.

Adolescent↗

The development of subsensitivity to chlorpheniramine.

To assess the development of subsensitivity to antihistamines, titrated prick skin test (PSTs) were performed to seven fivefold dilutions of histamine and either morphine or antigen at specific intervals during therapy. Ten subjects received chlorpheniramine, 24 mg per day, and placebo in a double-blind crossover study. Total wheal area was measured at baseline and after 1, 3, 7, 21, and 24 days. The dose of chlorpheniramine (or placebo) was doubled from days 22 to 24 to assess the response to dosage increase. Serum levels of chlorpheniramine were measured at days 3 and 21 in six patients. Maximal skin test suppression was observed on days 3 or 7. On day 21 there was significantly less (p less than 0.01) suppression of all PSTs than on days 3 or 7. Mean serum chlorpheniramine was 48.7 ng/ml on day 3 and 36.1 ng/ml on day 21 (not significant). There was no significant correlation between changes in serum chlorpheniramine levels and changes in PST suppression. Doubling the dose of chlorpheniramine did not achieve the maximal suppression observed at days 3 or 7. We conclude that subsensitivity to antihistamines develops between 7 and 21 days of therapy and cannot be completely overcome by doubling the dose. The decreased effect does not appear to be due to induced metabolism but may be related to increased H1 receptor number.

Adolescent↗

Skin test suppression by antihistamines and the development of subsensitivity.

The suppression of skin test reactivity by single doses of six antihistamines was measured before and after a period of daily antihistamine ingestion in 18 subjects. Single doses of hydroxyzine, 50 mg; chlorpheniramine, 16 mg; and promethazine, 50 mg; induced significant suppression of skin test reactivity at 2 hr, whereas the suppression produced by tripelennamine, 100 mg; diphenhydramine, 50 mg; and cyproheptadine, 16 mg; did not differ significantly from that produced by placebo. After 3 wk of treatment with hydroxyzine, 75 mg per day, the suppressive effect of hydroxyzine as well as the five clinically unrelated antihistamines was significantly reduced. Although the response to chlorpheniramine was also reduced after chronic treatment with chlorpheniramine, 24 mg per day, the difference was not statistically significant. We conclude that antihistamines in the doses used differ greatly in their suppressive effect on skin test reactivity. The antihistamine producing the most skin test suppression, hydroxyzine, when it was taken daily for 3 wk, caused the development of partial tolerance not only to its own effect but to those of clinically unrelated antihistamines.

Adolescent↗

Use of modified radioallergosorbent testing in determining initial immunotherapy doses.

Proponents of the modified radioallergosorbent test (RAST) for allergy diagnosis claim an advantage over skin testing in that immunotherapy may often be safely begun at higher initial concentrations and maintenance achieved with fewer injections than with conventional schedules. The resulting fewer visits would offset the greater initial cost and the delay in obtaining results. The most important allergen for 58 consecutive patients with seasonal allergic rhinitis beginning immunotherapy was determined from the history, skin testing, and aeroallergen surveys. A modified RAST was performed for these allergens. Thirty-nine patients (67%) had a modified RAST class 5 (most severe); 18 patients (31%) were class 4, and one patient was class 3. Since the initial concentration and total number of injections projected to reach maintenance vary little between our conventional schedule (1:100,000 w/v, 23 injections), and those for class 5 (1:62,500 w/v, 27 injections) and class 4 (1:12,500 w/v, 21 injections), the modified RAST offers no advantage over skin testing and conventional immunotherapy dosing in our patient population.

Adolescent↗

The Bela Schick lecture for 1985. The atopic diseases.

Review of the atopic diseases suggests a redefinition of the term "atopy" is indicated to reflect new information that has become available during the 60 years since the term was introduced. Atopy may be viewed as a manifestation of a still undefined defect. It is characterized by certain clinical findings and frequently by derangement of the immune and autonomic nervous systems. The atopic diseases are a group of seemingly unrelated conditions--eczema, asthma, rhinitis, hypertrophic sinusitis, and perhaps vernal conjunctivitis and migraine--which cluster in individuals and families. In the respiratory tract and eye, eosinophils in the tissues and secretions are characteristic and are not dependent on the presence of immediate hypersensitivity. Symptoms suggestive of basophil and mast cell mediator release are common to all the atopic diseases, and there is some evidence that nonimmunologic mediator release is enhanced in atopic patients. In the most clearly defined atopic diseases, eczema and asthma, approximately 80% of patients have an increased IgE response to normal environmental allergens. Accompanying and perhaps underlying these enhanced IgE responses are deficiencies of T cell numbers and function particularly in the suppressor T lymphocytes. Evidence exists that decreased beta-2-adrenergic and increased cholinergic and alpha-adrenergic responsiveness accompany and perhaps underlies the atopic diseases irrespective of the presence or absence of allergy.

Adrenergic alpha-Agonists↗

Cross-allergenicity among the grasses.

RAST inhibition was employed to determine the allergenic relationship of five common western grasses (brome, quack, western wheat, salt, and grama), three southern grasses (Bermuda, Johnson, and Bahia), and six common northern grasses (timothy, June, rye, red top, meadow fescue, and sweet vernal). The patterns of cross-allergenicity suggested by these studies were compared to those suggested by the botanical classification of these grasses. There was significant cross-allergenicity among the grasses studied. Brome, western wheat, and quack grasses demonstrated RAST inhibition patterns similar to the northern grasses. Salt and grama grasses exhibited close allergenic relationships to Bermuda grass, which was allergenically distinct from the northern grasses. Johnson grass appeared to share allergenicity with both the northern grasses and Bermuda grass. Bahia shared allergenicity with the northern grasses, but also possessed some unique allergens. Timothy and Bermuda grass appeared to account for all of the RAST-inhibiting activity contained in the other grasses studied with the possible exception of Bahia grass.

Cross Reactions↗

House dust mites in Colorado.

Sixty-four samples of house dust from 16 long-established households in the Denver, Colorado area were analyzed for the presence of house dust mites (Dermatophagoides sp.). No mites were found in house dust from 12 of the sampled houses and small numbers (10 to 40 mites/g of house dust) were found from the other four. In an additional four houses which contained furniture recently imported from other areas, 100 to 360 mites/g of dust were found, and 2 years later up to 200 mites/g were still present. Twenty-eight percent of the mites in repeat collections from the latter homes were alive. The mite allergen content of house dust samples was analyzed by RAST inhibition against pooled sera from mite allergic patients. When dust from four long-established Denver households where no mites were found was employed, there was an average binding of 37.2%; with dust from the four Denver households with low levels of mites and no imported furniture, binding averaged 39.5%. In contrast, with house dust from four "positive control" homes in California and New York there was only 26.1% binding (P less than .005). The results of this study suggest that there are small numbers of nonintroduced house dust mites in some Denver houses, but that they contribute little mite antigen and are probably of minimal clinical significance in mite-sensitive patients. Large numbers of mites can be introduced with furnishings and may persist for at least 2 years. Similar small mite populations might be expected in other areas with comparable relative humidity.

Allergens↗

Nutritional immunity: a prospective study of thirty-three patients with acute appendicitis.

During a recent 12-month period, serum iron levels, total iron binding capacities (TIBC), and latent iron binding capacities (LIBC) were studied preoperatively and 72 hrs postoperatively in 33 consecutive patients with pathologically confirmed acute appendicitis. Preoperative serum iron levels were significantly reduced in these patients (mean serum iron 32 micrograms/dl; P less than .0001) compared to established normal values (mean 100 micrograms/dl). LICBs were correspondingly elevated whereas TIBCs and mean hemoglobin values remained within the normal range. The reduced availability of serum iron in response to an acute infectious challenge such as appendicitis supports earlier experimental studies by others which suggest that nutritional immunity participates in host resistance to infection. In this study, the degree of serum iron suppression was directly related to the severity of disease (P less than .01).

Adolescent↗

What is atopy? Sidestepping semantics.

Atopy may be viewed as the manifestation of a still-undefined defect. It is characterized by certain clinical findings and frequently by derangements of the immune and autonomic nervous systems. The atopic diseases are a group of seemingly unrelated conditions--eczema, asthma, rhinitis, and perhaps hypertrophic sinusitis, vernal conjunctivitis, and migraine--which cluster in individuals and families. In the respiratory tract and eye, eosinophils in tissues and secretions are characteristic and are not dependent on the presence of immediate hypersensitivity. Symptoms suggestive of mast-cell mediator release are common to all the atopic diseases, and there is some evidence that nonimmunologic mediator release is enhanced in atopic patients. In the most clearly defined atopic diseases, eczema and asthma, approximately 80% of patients have increased IgE responses to normal environmental allergens. Accompanying and perhaps underlying the enhanced IgE responses are deficiencies of T cell numbers and function, particularly in suppressor T lymphocytes. Evidence exists that decreased beta 2-adrenergic function and increased cholinergic and alpha-adrenergic responsiveness accompany and perhaps underlie the atopic diseases, whether allergic or nonallergic.

Asthma↗

Evaluation of combined H1- and H2-receptor blocking agents in the treatment of seasonal allergic rhinitis.

During an 8 wk period (September 23 to July 30) 23 patients with histories of late-summer allergic rhinitis received, on a random basis, alternating 2 wk courses of either chlorpheniramine (anti-H1), 12 to 48 mg/day, plus placebo, or anti-H1 in the same dose plus cimetidine (anti-H2), 300 mg t.i.d. Symptom (SX) and medication (MED) scores were recorded twice daily. After the season the immediate (ICR) and late (LCR) reactions to allergens and histamine were measured in six of these patients while on: (1) no drugs, (2) anti-H1 plus placebo, or (3) anti-H1 plus anti-H2 in the doses employed during the season. Mean weekly SX scores were significantly lower on anti-H1 plus anti-H2 compared with anti-H1 plus placebo during the sixth week of the study (p less than 0.001). MED scores were lower on the anti-H1 and anti-H2 combination than on anti-H1 alone during weeks four and five (p less than 0.02). In the six patients studied after the season, the ICRs were consistently smaller with the anti-H1 and anti-H2 combination, but the differences were only significant for the histamine-induced wheal (p less than 0.01). In this study of allergic rhinitis there appeared to be a small but statistically significant additive effect of anti-H2 to the clinical response to anti-H1. No additional side effects were noted.

Adolescent↗

The bronchodilator response to inhalation of increasing doses of aerosolized albuterol.

Forty-four asthmatic patients were treated on separate days with increasing doses of albuterol in four double-blind studies that included placebo controls. Twenty-six subjects received one, two, four, six, and eight inhalations from a metered dose inhaler; 18 subjects received 1.25, 2.5, 5, 10, and 15 mg delivered by IPPB. There was a significant linear relationship in both groups between the maximum increase in FEV1 and the log dose of albuterol. The response to four, six, and eight inhalations from the metered dose inhaler was significantly greater than the response to one inhalation, and the response to 15 mg by IPPB was significantly greater than the response to any other dose by IPPB. The results suggest that in many patients maximum possible bronchodilation is not achieved by customarily recommended doses.

Administration, Intranasal↗