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Biomedical subjects

S Ting

Publications and source records attributed to S Ting.

At least 37 records · Page 2Linked to original sources
PubMed1985

Metered dose inhaler induced bronchospasm in asthmatic patients.

Beta-adrenergic agonists in metered dose inhalers (MDIs) are used extensively in the treatment of asthma. Previously we reported that 23 of 1450 (1.6%) of our asthmatic patients experienced immediate bronchoconstriction after using MDI-albuterol. In this study we investigated immediate bronchoconstriction after use of MDI-metaproterenol and after placebo-inhaler with "inert ingredients" only. Results suggest that those patients who complained of chest tightness or lack of relief following the use of MDI beta-adrenergic agonists are having true bronchoconstriction. The bronchoconstrictive response is most likely caused by the propellants or the other inert ingredients contained in these MDIs.

Administration, Intranasal↗
PubMed1985

Food allergy and adult migraine: double-blind and mediator confirmation of an allergic etiology.

Foods as a cause for migraine attacks were evaluated in 43 adults with recurrent migraine. Skin testing, elimination diets, double-blind challenges, and measurements of plasma histamine were performed. Thirteen subjects experienced 66% or greater reduction in headache frequency during a diet trial. Six subjects became headache free. Eleven of 16 skin test-positive patients responded to diet manipulation, while only two of 27 skin test-negatives did (P less than .005). Seven subjects agreed to double-blind challenges. In five of seven, at least one food provoked migraine. Placebo challenges did not provoke migraine. In three subjects, plasma histamine rose during migraine provoking challenges. The relationship between food ingestion and migraine is based in part on allergic mechanism. Tests for IgE-specific food allergy appear helpful in selecting patients likely to benefit from diet therapy.

Adolescent↗
PubMed1985

The incidence and clinical implications of hypersensitivity to papain in an allergic population, confirmed by blinded oral challenge.

Five hundred allergy clinic patients were prick skin tested with papain, 1 mg/mL, in addition to usual local aeroallergens. Five of 475 subjects with seasonal allergic disease had positive skin tests to both papain and local pollens. None of the 25 individuals with negative skin test to pollens had skin reactivity to papain. The five subjects with positive skin tests to papain underwent double-blind placebo-papain challenges. All papain challenges were positive. Placebo challenges were negative. Papain-induced symptoms included palatal itching, watering itchy eyes, sneezing, rhinorrhea, abdominal cramps, diarrhea, and diaphoresis. Circulating papain-specific IgE was detected in all the papain-sensitive individuals, but not in control subjects. Confirmed papain sensitivity occurred in 1.05% of allergic subjects. In the papain-sensitive patients, cross-reacting antibodies with chymopapain were found. The small number of non-allergic subjects did not show any papain or chymopapain sensitivity in vitro.

Administration, Oral↗
PubMed1984

A comparison between streptokinase/streptodornase and streptokinase on delayed hypersensitivity skin testing.

The use of streptokinase (SK) to replace streptokinase/streptodornase (SK/SD) in delayed hypersensitivity skin testing was evaluated in 325 patients. Sixty patients responded to SK/SD (100 U of SK per 25 U of SD) and 36 to SK (375 U). Thirty-two responded to SK/SD but not to SK, and eight responded to SK but not to SK/SD. SK, at the dosage used, is not a suitable substitute for SK/SD in delayed hypersensitivity testing. SD may be the more potent recall antigen. Perhaps more importantly is that of 250 positive responders to a recall-antigen battery consisting of SK/SD, SK, Candida, Trichophyton, tetanus toxoid, purified protein derivative, and coccidioidin, 99.2% (248) would have been detected had the testing for SK and SK/SD not been done.

Adult↗
PubMed1984

Effects of cromolyn on codeine-induced histamine release in vivo.

Cromolyn has been shown to inhibit histamine release from mast cells induced by various stimuli in vitro. However, the local effects of cromolyn on codeine-induced wheal and flare skin reactions are not well understood. Intradermal injection of codeine induced prominent whealing in almost all humans. We studied the effect of local cromolyn injection on codeine-induced skin reactions, histamine release, and ultramicroscopic changes in mast cells in 10 volunteers. The finding in this study showed that injection of a 2% cromolyn solution before or together with the codeine injection does not affect the subsequent skin reactions, histamine release and ultramicroscopic changes of mast cells.

Codeine↗
PubMed1983

Nonfamilial, vibration-induced angioedema.

Vibratory angioedema is a rare form of physical angioedema. A Mexican-American boy presented with vibration-related prolonged angioedema of the hands at age 16. After the use of a controlled vibratory stimulus, 10 volunteers and seven members of the family (three generations) developed expected transient erythema and whealing reaction of the skin at the site of contact. However, with the same vibrating stimulus the patient developed large erythematous swelling that lasted for 12 hr. Vibratory challenge study revealed a rapid rise and fall in plasma histamine. No increase in levels of plasma histamine were detected from the nonstimulated arm. Prausnitz-Küstner testing was negative. Light and electron microscopic study of the mast cell revealed degranulation and extensive fragmentation of the granules from the stimulated site. No degranulation was seen in the contralateral unstimulated site. A state of tolerance to vibration was induced by graded increased exposure to vibratory stimulus and the patient's clinical problem was eliminated.

Adolescent↗
PubMed1983

Terbutaline modulation of human allergic skin reactions.

Terbutaline, a preferential beta 2-adrenergic agonist, has been shown to inhibit allergen-induced histamine release in vitro. In contrast, orally administered therapeutic doses of terbutaline do not inhibit antigen-induced wheal and flare reactions. We studied the effects of local terbutaline on antigen-induced whealing response, histamine release, cellular inflammatory response, and ultramicroscopic mast cell changes in antigen-challenged skin sites in ragweed-sensitive subjects. Results showed that ragweed challenge significantly induced increased histamine release in all subjects. In contrast, no such histamine release was observed at sites challenged with antigen in the presence of terbutaline. Thus locally applied terbutaline in nontoxic doses modulates mediator release in certain allergic reactions.

Biopsy↗
PubMed1983

Cromolyn does not modulate human allergic skin reactions in vivo.

Cromolyn pretreatment frequently reduces antigen inhalation-induced bronchospasm possibly by inhibiting mast cell degranulation and mediator release. However, the local effects of cromolyn on type I hypersensitivity skin reactions are not well understood. We studied the effect of local cromolyn on antigen-induced skin reaction, histamine release, cellular inflammatory response, and ultramicroscopic changes of mast cells in 10 ragweed-sensitized subjects. Results showed that cromolyn 2% (nonirritant dose) does not modulate ragweed-induced skin whealing response, histamine release, and ultramicroscopic changes of mast cells. Thus, unlike the situation in the tracheobronchial tree, allergic skin reactions and associated events are not inhibited by local cromolyn application.

Adult↗
PubMed1983

Effect of cimetidine on exogenous histamine inhibition of histamine release in vivo.

We previously reported that exogenous histamine inhibits in vivo histamine release and eosinophil accumulation in ragweed-challenged skin sites of sensitive human subjects. The mechanism(s) involved were unclear. In this study, we repeated similar approaches in four of the same subjects pretreated for 3 days with cimetidine, an H2 receptor antagonist. The pattern of exogenous histamine effects was now different in that local exogenous histamine (50 ng/ml) did not significantly alter ragweed-induced mast cell alteration, histamine release, or the degree of eosinophil accumulation in skin challenge sites. These findings suggest that the observed exogenous histamine inhibitory effects may be mediated through the H2 receptor.

Biopsy↗
PubMed1983

Effects of ascorbic acid on pulmonary functions in mild asthma.

Twenty subjects with mild asthma took a short course of moderately high doses of Vitamin C (500 mg four times daily for 3 days and 1 g prior to spirometric evaluation). There were no differences in pulmonary functions just prior to and after therapy. There were no adverse reactions noted. If, as reported, Vitamin C has a beneficial effect in asthma, it does not appear to be due to a bronchodilatory effect.

Adult↗
PubMed1983

Liquid chromatographic determination of methyldopa and methyldopa-thiazide combinations in dosage forms.

A liquid chromatographic (LC) method, using a reverse phase C18 column, an acetic acid-methanol-water mobile phase, and detection at 280 nm, was developed for the determination of methyldopa in tablets and oral suspensions and combinations of methyldopa with hydrochlorothiazide or chlorothiazide in tablets. A mixture of these 3 drugs was resolved in less than 8 min. Detector responses were linear for the following amounts (mg/mL) of drug injected: methyldopa 0.031-0.393, chlorothiazide 0.019-0.114, and hydrochlorothiazide 0.004-0.083. Recoveries from commercial dosage forms ranged from 99.1 to 100.9% for methyldopa, 99.2-100.4% for chlorothiazide, and 100.0-101.2% for hydrochlorothiazide. Replicate injections of methyldopa, chlorothiazide, and hydrochlorothiazide standard preparations alone or in combination gave overall relative standard deviations of less than 1.6% (n = 10). The results for methyldopa tablets by the proposed method were in agreement with those obtained by the USP XX method. The LC method detected as little as 0.6 micrograms 3-O-methylmethyldopa/mL and 0.5 micrograms 4-amino-6-chloro-1,3-benzenedisulfonamide/mL, which are sometimes found as contaminants of methyldopa and thiazides, respectively, and resolved methyldopa from its methyldopa glucose adduct, a substance found in methyldopa oral suspensions.

Chlorothiazide↗
PubMed1981

Histamine suppression of in vivo eosinophil accumulation and histamine release in human allergic reactions.

Although it has been shown that histamine inhibits antigen-induced in vitro histamine release from basophils, it is unclear whether histamine inhibits in vivo mediator release in human allergic reactions. We report effects of exogenous histamine on histamine release and inflammatory cell responses in antigen-challenged skin sites in eight ragweed-sensitive individuals. Four heat-suction blisters in each subject were unroofed, and a collection chamber was appended to each blister base. Chamber A contained 1000 PNU/ml ragweed extract; chamber B contained buffered saline (control fluid); chamber C contained 1000 PNU/ml ragweed and 50 ng (5 x 10(-7) M) of histamine; and chamber D contained histamine alone (50 ng). Comparative analyses of chamber histamine levels in individual subjects showed that (1) histamine levels in chamber A were significantly greater than those in chamber B (p less than 0.01) and that histamine levels in chamber C were not significantly different than those in chamber D (p less than 0.5). Likewise, comparison of eosinophils attaching to membrane filters appended to the chamber bases for 2 hr showed that there were significantly more eosinophils in chamber A than in chamber B (p less than 0.01) and that there was no significant difference in eosinophil numbers on filters appended to chamber C vs chamber D. In three of four subjects studied, addition of exogenous histamine (50 ng/ml) to ragweed before intradermal injection inhibited the ultrastructural mast cell alterations seen within 10 min after injection of ragweed alone. In the one subject in which mast cell alterations were not prevented, exogenous histamine also did not inhibit antigen-induced histamine release or subsequent eosinophil accumulation in the skin chambers.

Eosinophils↗
PubMed1981

In vivo release of eosinophil chemoattractant activity in human allergic skin reactions.

A search was made for in vivo release of factor(s) that may be responsible for prominent eosinophil accumulations in human allergic skin reactions. Using a specially designed skin chamber appended to the base of unroofed skin blisters, we have found at ragweed-challenged sites in sensitive subjects the release of significantly greater histamine (15 +/- 3 ng/ml) than at control sites (3 +/- 0.5 ng/ml). Eosinophil accumulation after 2 hr was also significantly greater on membrane filters appended to ragweed-challenged sites than control sites (55 +/- 15 vs 4 +/- 0.5). Intradermal injection of ultrafiltrates of the chamber fluids from antigen-challenged sites, but not of fluids from control sites, induced prominent eosinophil accumulation (mean = 25/mm2) when injected intradermally in autologous uninvolved skin. Neither ultrafiltered antigen solution nor histamine (employed in concentrations similar to those released in the chambers) evoked such in vivo responses when injected intradermally in the same subjects (mean = less than 1/mm2). The eosinophil responses to injected ultrafiltered chamber fluid from antigen-challenged sites peaked at 30 min, whereas even greater eosinophil responses to unaltered antigen started after 60 min. These findings suggest that in vivo release of a low m.w. factor or factors other than histamine is very likely responsible for at least part of the in vivo eosinophil accumulation in human allergic reaction sites. Additional findings suggest that a significant portion of the time lag between intradermal antigen and dermal eosinophil accumulation is encompassed by local mediator release.

Asthma↗
PubMed1980

Inappropriate secretion of antidiuretic hormone after open heart surgery.

After open heart surgery for the closure of an atrial septal defect, acute brain syndrome developed in a 5-year-old girl, this being documented by laboratory evidence of the syndrome of inappropriate antidiuretic hormone secretion (SIADH). Irritability and total disorientation were the first symptoms observed. She completely recovered after being treated with hypertonic saline solution and fluid restriction. The potentially serious outcome of the SIADH warrants early recognition and appropriate measures in children who suffer acute brain syndrome after open heart surgery.

Cardiac Surgical Procedures↗
PubMed1980

Patterns of mast cell alterations and in vivo mediator release in human allergic skin reactions.

Patterns of in vivo histamine release in skin sites challenged with ragweed antigen were compared in five human subjects sensitive to this antigen and four nonallergic individuals, using a newly developed skin-chamber technique. These findings were compared with inflammatory cell responses in the reaction sites and patterns of ultramicroscopic mast cell alterations in biopsy specimens of skin tests in the same subjects. Definite mast cell alterations occurred within 15 sec and appeared maximal within 5 to 10 min after antigen injection. Histamine levels in appended chambers increased after a lag of 10 to 30 min and were elevated for at least 60 min after antigen challenge. Eosinophils accumulated only in antigen-induced reaction sites. However, there was no precise quantitative correlation among the degree of change in these three measurements. These appear to be promising approaches to further in vivo studies of human allergic reactions.

Antigens↗
PubMedDate not supplied

Liquid chromatographic determination of levodopa, levodopa-carbidopa, and related impurities in solid dosage forms.

A rapid reverse phase liquid chromatographic method was developed for the determination of levodopa and levodopa-carbidopa in tablets and capsules. The method also separates these drugs from 3-(3,4,6-trihydroxyphenyl)alanine and methoxytyrosine, impurities of levodopa, and from methyldopa and 3-O-methylcarbidopa, impurities of carbidopa. The mobile phase was 3% acetic acid and the detection wavelength was 280 nm. The method was linear over the concentration range 0.05-0.40 mg levodopa/mL, 0.01-0.06 mg carbidopa/mL, 0.9-12.8 micrograms 3-(3,4,6-trihydroxyphenyl)alanine/mL, 0.7-3.1 micrograms methyldopa/mL, 5-20 micrograms methoxytyrosine/mL, and 0.5-3.3 micrograms 3-O-methylcarbidopa/mL. Mean recoveries (%) for spiked commercial tablets were: levodopa 100.3, carbidopa 100.4, 3-(3,4,6-trihydroxyphenyl)alanine 99.1, methoxytyrosine 100.0, methyldopa 100.0, and 3-O-methylcarbidopa 99.4.

Acetaminophen↗