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Biomedical subjects

H S Nelson

Publications and source records attributed to H S Nelson.

At least 19 recordsLinked to original sources
PubMed1992

Evaluation of in vivo breast fine needle aspirates by flow cytometry: an efficacy study.

BACKGROUND: Malignancy of the breast is frequently diagnosed through fine needle aspiration. In the hands of a skilled aspirator and cytopathologist, this can be a highly accurate procedure. PURPOSE: This study was undertaken to evaluate whether sufficient residual cells in the bore of the needle could be harvested and analyzed efficiently by flow cytometry analysis. The goal was then to determine the value of routine flow cytometry as an adjunctive technology in the interpretation of breast fine needle aspirations. METHODS: Cells were rinsed from the needles of 83 consecutive diagnostic fine needle aspirates after preliminary inspection had confirmed adequate material was obtained for cytopathology. Cells were washed, and nuclei prepared by detergent treatment. After ribonuclease treatment, DNA was stained with the fluorescent marker propidium iodide. DNA content per cell was determined by flow cytometry by measurement of right-angle fluorescence. RESULTS: Less than 4% of the samples were rejected for inadequate cell numbers. Flow cytometry criteria for evidence of malignancy included the presence of a DNA aneuploid population or an elevated rate of proliferation (13% or higher) of a diploid population. Accuracy of flow cytometry was based on cytopathologic interpretation in all cases except two which were based on results of excisional biopsy. The sensitivity of the flow cytometry analysis was 76%; the specificity was 100%, with results from flow cytometry pivotal in the correct diagnoses for two patients whose cytopathologic results were equivocal. Analysis of histograms indicated acceptable coefficients of variation for all populations. Gating analysis indicated the suitability of the material for this type of study, with an average of 85% of the events selected, or "gated in." Low recoveries were associated with the presence of necrotic debris in the sample. CONCLUSION: Flow cytometry can be a valuable adjunctive technology, capable of providing the cytopathologist with additional information regarding the character of cells analyzed.

Biopsy, Needle↗
PubMed1992

Treatment of peanut allergy with rush immunotherapy.

Peanut and peanut products are a common food in the diet. Peanuts are also one of the most common foods responsible for food-induced anaphylaxis. Patients rarely lose sensitivity to peanuts. Although the ideal treatment is avoidance, this is often not possible because of hidden exposures; therefore, a more effective treatment is needed. Subjects with confirmed peanut allergy were treated in a double-blind, placebo-controlled study with peanut immunotherapy or placebo. Objective measures of efficacy included changes in symptom score during double-blind placebo-controlled peanut challenge (DBPCPC) and titrated end point prick skin tests (PST). Three subjects treated with peanut immunotherapy completed the study. These subjects displayed a 67% to 100% decrease in symptoms induced by DBPCPC. Subjects also had a 2- to 5-log reduction in end point PST reactivity to peanut extract. One placebo-treated subject completed the study. This subject had essentially no change in DBPCPC symptom scores or PST sensitivity to peanut. Two other placebo-treated subjects underwent a second PST session. These subjects had a 1- to 2-log increase in skin test sensitivity to peanut. All peanut-treated subjects were able to reach maintenance dose, and in no case did an anaphylactic reaction occur secondary to the peanut immunotherapy. The current study provides preliminary data demonstrating the efficacy of injection therapy with peanut extract and provides a future line of clinical investigation for the treatment of this potentially lethal disease. It should be noted, however, that the rate of systemic reactions with rush immunotherapy was 13.3%.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Use of standardized and conventional allergen extracts in prick skin testing.

This study examined whether commercially available conventional and standardized allergen extracts differ enough in potency to affect routine prick skin test results. Extracts of white oak, timothy, Bermuda, Russian thistle, short ragweed, sagebrush, Alternaria, and cat dander were examined in allergic patients and in nonatopic subjects with no personal or family history of asthma, rhinitis, or eczema. Conventional nonstandardized extracts (1:10 or 1:20 wt/vol) from two sources were compared with three concentrations (100,000, 10,000, and 1000 AU/ml) of a single standardized extract. Preparations were compared in the allergic patients with computerized planimetry, and in all patients and subjects with a conventional skin test grading system. Skin test area for the conventional extracts generally fell between the 10,000 and 100,000 AU/ml concentrations of the standardized extract. Skin test reactivity to at least one allergen extract occurred in 31% of the nonatopic subjects; there was no difference between the number of 3+ and 4+ reactions for conventional and standardized extracts. Results indicate that standardized and conventional extracts are frequently similar, but are not directly interchangeable.

Adolescent↗
PubMed1992

Aerobiology of the Colorado Rockies: pollen count comparisons between Vail and Denver, Colorado.

Pollen patterns were compared between Vail, CO (8,200 feet elevation), Aspen, CO (7,900 feet) and Denver, CO (5,280 feet) from 1984 through 1988. Counts were obtained at all sites with a volumetric intermittent cycling rotating impaction sampler. Aspen and Denver were compared in 1984, and Vail and Denver from 1985 through 1988. While counts were generally lower in the mountain sites than Denver, certain pollens, especially trees, were quite high. Ragweed was essentially absent from Aspen and Vail, and chenopod-amaranth counts were very low. Cedar, pine, and aspen frequently pollinated despite active snowfall.

Air Pollution↗
PubMed1992

Flow cytometric analysis of pulmonary fluids and cells for the detection of malignancies.

Cells from a pulmonary or bronchial origin were analyzed with flow cytometry to assess the sensitivity and specificity of this method in diagnosing malignancy. In all instances, cells submitted for flow cytometry analysis were excess cells from specimens submitted for routine cytology. Less than 3% of all samples were rejected for insufficient material. Overall sensitivity from all sources was 86%, specificity 96%. Although cytology results were the standard for determining accuracy of flow cytometry, in a few patients cytology appeared normal and initial evidence for malignancy was obtained from flow cytometry. For this reason, flow cytometry may be a valuable adjunctive technology in the diagnosis of malignancy.

DNA↗
PubMed1991

An examination of food hypersensitivity as a cause of increased bronchial responsiveness to inhaled methacholine.

To determine if food challenges could alter bronchial hyperresponsiveness, methacholine challenges were performed before and 24 hours after double-blind, placebo-controlled food challenges on 11 subjects with asthma with a history of food-induced asthma and positive skin prick tests to the suspect food. An equal number of patients demonstrated increased methacholine sensitivity after food and placebo challenges. Thus, we could not find evidence that allergic reactions to food induced bronchial hyperresponsiveness.

Adult↗
PubMed1991

Extreme variability in aerosol output of the DeVilbiss 646 jet nebulizer.

Ten new jet nebulizers (DeVilbiss 646) were studied to determine their consistency of output. Each nebulizer, containing 2 ml of saline solution, was run for 1 min in triplicate at four different straw (capillary tube) positions, keeping all other variables constant. Total output in milliliters per minute and volume of aerosol in the respirable range (1.0 to 5.0 microns) were measured. There was significant variability in output and volume of output in the respirable range (VORR) for every nebulizer at each of the tested straw positions (p less than 0.0001). Irregularities in manufacture of the bowl and straw appear to be responsible for this significant variability. In summary, there is considerable intranebulizer and internebulizer variability that could influence both patient care and medical use for diagnostic purposes.

Confidence Intervals↗
PubMed1991

Double-blind study of suppression of indoor fungi and bacteria by the PuriDyne biogenic air purifier.

The PuriDyne Air Purification System was studied in a double-blind trial for its ability to reduce the prevalence of bacteria and fungi in residential units. Twelve apartments were studied employing an Andersen Sampler for airborne fungi and Rodac plates for surface bacteria. Following determination of baseline levels, PuriDyne units with active filters were installed in six apartments, and units with inactive filters in six others. Sampling continued weekly for 1 month while the Air Purifiers were in place and at the end of 2 weeks following their removal. There was no statistically significant difference in airborne fungal or surface bacterial levels between baseline and treatment periods for apartments with either active or inactive units, nor were there significant differences between the two groups at any time.

Air Pollutants↗
PubMed1979

Incidence of bronchoconstriction due to aspirin, azo dyes, non-azo dyes, and preservatives in a population of perennial asthmatics.

Forty-five patients with moderately severe perennial bronchial asthma were challenged by ingestion of: acetylsalicyclic acid (ASA); 4 azo dyes (tartrazine, sunset yellow, amaranth, and ponceau); 3 non-azo dyes (erythrosine, brilliant blue, and indigotin); sodium benzoate (NaB); parahydroxybenzoic acid (OHBA); butylated hydroxyanisole (BHA); and butylated hydroxytoluene (BHT). A fall in forced expiratory volume is one second (FEV1) greater than 25% from baseline was considered positive. Seven patients who gave an unequivocal history of aspirin intolerance were not challenged with ASA; an additional 13 had positive open challenges to ASA, giving an apparent incidence of aspirin sensitivity of 20/45. The presence of nasal polyps, simusitis, or the regular use of corticosteroids, either singly or in combination, was not associated with an increased incidence of reactions to ASA. Significant bronchoconstriction to open challenges with agents other than ASA was less frequent. Positive open challenges to all substances except aspirin were followed by double-blind challenges which were positive in only 3 instances: 1 each with erythrosine, ponceau, and NaB/OHBA. Our findings confirm that ASA intolerance is relatively common but suggest on the other hand that reactions to dyes and preservatives are uncommon cause of clinically significant bronchoconstriction in moderately severe perennial asthmatics.

Adolescent↗
PubMed1979

Aerosolized terbutaline in asthmatics. Comparison of dosage strength, schedule, and method of administration.

Sixteen patients with bronchial asthma participated in three studies of inhaled terbutaline. Onset of action, duration, and peak effects were compared for a dose of 0.5 mg given in one, two, or four inhalations at 1 min intervals from a freon-propelled, metered-dose aerosol. There was no significant difference in the response between the schedules. Dose-response curves were compared for terbutaline from a metered-dose aerosol, and pressure nebulized with and without intermittent positive pressure breathing (IPPB). There was no difference between the response with IPPB and simple nebulization. Improvement continued to the total dose administered of 9.0 mg. For a given bronchial response, six to eight times as much terbutaline was required by pressure nebulization as from the metered-dose aerosol.

Adolescent↗