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Biomedical subjects

H S Nelson

Publications and source records attributed to H S Nelson.

At least 91 records · Page 5Linked to original sources
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↗
PubMed1990

Immediate skin test reactivity to Food and Drug Administration-approved standardized extracts.

In an effort to determine whether recently introduced Food and Drug Administration-approved standardized extracts produce clinically appropriate responses in a population, 200 subjects were skin prick tested (SPT). Thirteen extracts (10 pollens, two house dust (HD) mites and cat) were tested in three groups of subjects, 50 with a history of asthma or allergic rhinitis (AL), 50 without asthma or perennial or seasonal allergic rhinitis but with a positive immediate family history for these conditions (FAL), and 100 subjects without a personal or family history for these conditions (NAL). An SPT mean wheal diameter greater than or equal to 3 mm was considered positive. Ninety percent (95% confidence interval [CI], 82% to 98%) of AL subjects had at least one positive SPT. Forty-six percent of FAL subjects (95% CI, 30% to 58%) and 29% of NAL subjects (95% CI, 20% to 38%) had at least one positive SPT. More FAL than NAL subjects had at least one SPT (p less than 0.05), and FAL subjects had more positive SPTs than NAL subjects (p less than 0.05), further supporting the genetic regulation of allergen-specific IgE production. Of the five AL subjects with no SPT wheal greater than or equal to 3 mm, three subjects were available for intradermal tests. Thirteen nonstandardized allergens similar to allergens used for SPT were applied intradermally in each of these three subjects and were all negative. Compared with history, an SPT wheal greater than or equal to 3 mm to cat produced a sensitivity of 0.90, a specificity of 0.90, and diagnostic accuracy of 0.90. Tenfold dilutions of pollens and cat reduced sensitivity without significantly improving specificity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Chronic urticaria exacerbated by the antioxidant food preservatives, butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT).

Two patients with chronic idiopathic urticaria in whom remissions were achieved with dye- and preservative-elimination diet had exacerbations of their urticaria when they were challenged under double-blind, placebo-controlled conditions with butylated hydroxyanisole and butylated hydroxytoluene. After elimination of butylated hydroxyanisole and butylated hydroxytoluene from their diets, there was marked abatement of the frequency, severity, and duration of their urticaria. These antioxidants appear capable of aggravating symptoms in certain patients with chronic urticaria.

Acetaminophen↗
PubMed1990

Drug allergy. Best diagnostic and treatment approaches.

The problems in identifying and managing drug allergy are myriad, primarily because of the number of possible agents involved, the lack of objective diagnostic methods, and the varied signs and symptoms that may occur. Allergic reactions can be life-threatening and are avoidable in most cases. A careful and serious approach is important because the effect of medical decisions can be significant. Physicians should keep in mind that an allergic reaction to any drug can occur in any patient at any time.

Anesthetics↗
PubMed1990

Endometriosis of the abdominal wall.

Endometriosis of the abdominal wall typically occurs as a painful mass in a lower abdominal incision from previous cesarean section or hysterectomy. Most patients are young and in their active reproductive years. The histologic diagnosis requires a combination of either endometrial-like glands, endometrial stroma, or hemosiderin pigment. The diagnosis must be considered in any woman with an abdominal wall mass and a history of transabdominal gynecologic surgery. Wide excision offers the best chance to prevent recurrence.

Abdominal Muscles↗
PubMed1990

Efficacy of atropine methylnitrate alone and in combination with albuterol in children with asthma.

The bronchodilator effect of nebulized AMN, albuterol and their combination was evaluated in 16 steroid-dependent asthmatic children. In phase 1, maximal bronchodilation was determined by dose-response studies on separate days. Maximal bronchodilator dose of each drug was administered either alone or in combination during phase 2. In phase 1, 0.11 +/- 0.01 mg/kg of albuterol and 0.03 mg/kg of AMN produced maximum bronchodilation. In phase 2, the peak response to albuterol occurred within 30 min and to AMN, at 60 min. Maximal FEV1 achieved after AMN was 90 percent of the maximal achieved after albuterol. AMN FEV1 response was better than for placebo for 3 h; that for albuterol was better for 4 h. Combination therapy produced a peak response similar to that of albuterol but was better than albuterol by 6 h. Thus, the maximum bronchodilator effect of AMN is less than that of albuterol in asthmatic children, but the combination may extend the period of bronchodilatation.

Adolescent↗
PubMed1990

A random double-blind trial of the combination of nebulized atropine methylnitrate and albuterol in nocturnal asthma.

The combination of nebulized atropine methylnitrate (AMN) and a beta-agonist has been shown to produce greater and longer lasting bronchodilation than either drug alone. We examined the efficacy of the combination in diminishing the "morning dipping" in PEFR in eight hospitalized but stable asthmatics. The patients received nebulized albuterol along with either AMN (AMN + ALB) or placebo (ALB) in a random double-blind cross-over fashion at 10 PM on four nights. PEFR and FEV1 were recorded at 6 PM, 10 PM, and 6 AM before the administration of bronchodilators. There was no statistically significant difference between ALB and AMN + ALB in reducing the morning dipping in these patients.

Administration, Inhalation↗
PubMed1989

Vitamin B6 levels in patients with carpal tunnel syndrome.

Vitamin B6 levels were determined in patients with idiopathic carpal tunnel syndrome. Results from this limited study strongly suggest that vitamin B6 deficiency may accompany carpal tunnel syndrome. This study did not address the question of the causal relationship between vitamin B6 status and development of symptoms.

Carpal Tunnel Syndrome↗