Analysis of meteorologic variables and seasonal aeroallergen pollen counts in Denver, Colorado.

BACKGROUND: The observation of low levels of weed pollens following a freeze and an early autumn snowfall in Denver, Colorado led to this analysis of meteorologic variables and pollen counts. OBJECTIVE: The purpose of this study was to examine, in depth, the relationship between observed pollen counts and a selection of independent meteorologic variables. METHODS: We prospectively studied in 1991 daily high and low temperature, relative humidity, precipitation, barometric pressure, percent sunshine, wind velocity and direction, tree, grass, and weed pollen, as well as dates of the first frost/freeze. Similar data were retrospectively analyzed for 1987-1990. RESULTS: Correlation coefficients for the prospective data were as high as .611 for high temperature and cottonwood and .718 for high temperature and maple (P < .001). High and low temperature showed strong correlations with the combined weed counts (.598 and .628, respectively, P < .001). CONCLUSIONS: Denver weed pollens appear impacted more by temperature and less by precipitation and humidity, while the converse is true for tree and grass pollen. However, weed pollen, especially sage, may appreciably rebound after freezing temperatures. While separate meteorologic variables may have high correlations with specific pollen counts in a given year, such effect is not consistent and varies from year to year.

Effect of terfenadine on urination.

Anticholinergic side effects of commonly used antihistamines are known to aggravate voiding difficulties in older men with benign prostatic hypertrophy. Newer antihistamines, such as terfenadine (Seldane), with less anticholinergic side effects may not have such an effect on voiding. We performed a randomized, double-blind, placebo-controlled, crossover study in eight normal male volunteers (phase I) and in 11 patients with documented benign prostatic hypertrophy (phase II) to study the effect of terfenadine on voiding. Subjects received either 60 mg of terfenadine or an identical placebo twice daily for 1 week each. After a 1-week washout period, they were crossed over to receive the other drug. Evaluation took place on days 0, 7, 14, and 21. Prick skin testing was performed with serial threefold dilutions of histamine to assess efficacy and degree of compliance. Uroflowmetry and urinary symptom assessment were also done. In phase I, after 1 week of terfenadine, mean skin test suppression was 83.8% compared with -0.5% with placebo (P < .01). Urinary peak flow increased 10.4% on terfenadine and 9.7% on placebo (P = NS). In phase II, the mean prick skin test suppression was 87.8% compared with 12.0% for placebo (P < .002). Urinary peak flow was decreased 0.1% from baseline on terfenadine and increased by 18.7% for placebo (P = NS). None of the subjects noted alterations in voiding symptom scores. We conclude that the commonly recommended dose of terfenadine does not significantly alter voiding characteristics in normal men or in patients with documented benign prostatic hypertrophy.

The role of food in the pathogenesis of migraine headache.

Recent textbooks of neurology and internal medicine cite food, or pharmacologic agents in foods, as provokers of migraine (1,2). Nevertheless, this area remains controversial. Many authorities recognize foods containing pharmacologic agents, such as tyramine, as possible provokers of migraine. However, the importance of foods lacking these properties is less clear. During the 1980s, there was renewed interest in food-induced migraine. Studies have attempted to address the incidence of food-induced migraine and have recently begun to study potential mechanisms. This paper will review the general features of migraine, including prevalence, differential diagnosis, and known provokers, and then focus on the link between food and migraine.

Methotrexate in the treatment of steroid-dependent asthma.

A double-blind, placebo-controlled, crossover study was designed to compare steroid requirements between placebo and methotrexate (MTX) treatment in subjects with corticosteroid-requiring asthma. Subjects began with a steroid taper and then were randomized to a 3-month trial of drug or placebo therapy. Subjects received 15 mg of MTX a week or identical placebo. A 1-month washout period was completed before the crossover trial. Symptom scores, peak flow rates, spirometry, and beta-agonist frequency were closely monitored. Ten subjects completed the study. The average dose of prednisone during the placebo-treatment period was 11.97 mg/day compared to 8.37 mg/day while subjects were taking MTX. This was a 30% reduction in daily steroid requirement (p less than 0.01). Symptom scores and spirometry did not differ between the crossover trials, and overall clinical status was not altered. Complications from MTX were mild and included anorexia, alopecia, and stomatitis. All complications resolved with dose reduction or when MTX was stopped at the end of the study. No subjects withdrew from the study because of MTX complications. Low-dose MTX significantly reduced the steroid requirement in this group of subjects with steroid-dependent asthma. This reduction in steroid requirement was obtained without altering clinical status and without significant complication.

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.

Hypereosinophilia, neurologic, and gastrointestinal symptoms after bee-pollen ingestion.

A patient developed hypereosinophilia (13,440 cells per cubic millimeter) 6 weeks after beginning the ingestion of bee pollen. Symptoms included generalized malaise, headache, nausea, abdominal pain diarrhea, generalized pruritus, and decreased memory. Evaluation revealed no other known cause for the patient's hypereosinophilia, which resolved after bee-pollen ingestion was stopped. The product contained a mixture of entomophilous and anemophilous pollens to which the patient was skin test positive. An open challenge with the bee pollen later reproduced the presenting symptoms with a concomitant rise of the eosinophil count from 207 to 890 cells per cubic millimeter. The patient has since remained well avoiding bee pollen. This study strongly suggests that hypereosinophilia with attendant pathophysiologic disturbances may be an adverse reaction to bee-pollen ingestion in atopic individuals.

Comparison of PEFR and FEV1 in patients with varying degrees of airway obstruction. Effect of modest altitude.

Measurements of FEV1 and PEFR performed on a Jones Pulmonor Spirometer (JPF) were compared with PEFR obtained with a mini-Wright peak flow meter (WPF) in 102 patients. Data were converted to percent predicted. Standard deviations of triplicate measurements were: FEV1, 3.01 percent; JPF, 7.22 percent; and WPF, 5.12 percent. Correlation of best of three measurements was FEV1-JPF r = .758; FEV1-WPF r = .744; and JPF-WPF r = .846. The mean percent predicted of the best of three values of FEV1 was 74.8 percent, JPF 91.4 percent, and WPF 94 percent. These higher values for percent predicted PEFR were obtained throughout the range of FEV1 values. Studies on nine normal volunteers in an atmospheric chamber suggested that higher altitudes may account for higher PEFR values. We conclude that PEFR, measured by either waterless spirometer or mini-Wright peak flow meter, has greater intrasubject variability than FEV1, and it tends to underestimate the degree of pulmonary impairment.

The development of subsensitivity to atropine methylnitrate. A double-blind, placebo-controlled crossover study.

This is a double-blind, placebo-controlled crossover study designed to assess the effectiveness of nebulized atropine methylnitrate (AMN) with chronic use. We studied 22 patients with asthma, 10 receiving theophylline and inhaled beta-agonists and 12 who were receiving corticosteroids as well. All had demonstrated at least a 15% change in FEV1 either spontaneously or after bronchodilator. Bronchodilator effect was measured serially for 4 h after inhalation of the initial dose and again after 2 wk of four-times-daily use. Significant bronchodilator effect was seen initially with AMN when compared to placebo (p less than 0.01). After 2 wk of use, the bronchodilator effect of AMN was significantly diminished as compared to the initial effect (p less than 0.01) but was still better than placebo (p less than 0.05). Subsensitivity did develop to varying degrees in the patients, but we were unable to identify any clinical parameters that would allow prediction of subsequent subsensitivity. We conclude that the development of subsensitivity to AMN occurs in certain patients with chronic administration but does not reflect a total loss of bronchodilator effect.

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.

Equilibration of intravascular albumin with lung lymph in unanesthetized sheep.

In 16 unanesthetized sheep with chronic lung lymph fistulas we measured pulmonary vascular pressures, lymph flow, lymph and plasma total protein and albumin concentration. We determined the rate of equilibration of radioiodinated albumin between plasma and lung interstitial fluid (lung lymph) in three steady-state conditions; baseline (n = 14), increased pulmonary microvascular pressure (n = 9) and increased microvascular permeability (n = 4). The tracer protein equilibration proceeded according to single compartment wash-in kinetics in all experiments. Lung lymph flow averaged 5.3 +/- 2.8 (S.D.)ml/h under baseline conditions, 16.1 +/- 10.6 ml/h during increased pressure and 37.3 +/- 29.4 ml/h during increased permeability. The half time of equilibration averaged 2.9 +/- 1.0 h, 2.2 +/- 1.0 h and 0.7 +/- 0.2 h, respectively. Lung interstitial fluid equilibrates with plasma proteins more rapidly than most other organs. The marked difference between increased permeability and the other conditions demonstrates the sensitivity of this method. No evidence was obtained that any tracer protein entered lung lymph within the caudal mediastinal lymph node.

Indicator dilution lung water and capillary blood volume in prolonged heavy exercise in normal men.

The indicator dilution quantity of extravascular water in the lung (idQwl) increases in exercise, but whether it is a real accumulation of fluid or is due to increased distribution of blood flow to previously unperfused regions of alveolar walls is unsettled. In 9 well-trained young men, we compared idQwl and the pulmonary capillary blood volume, as measured by the carbon monoxide diffusing capacity procedure, at rest and after 10 and about 50 min of heavy work (150 watts) on a bicycle ergometer. From rest to 10-min exercise, we observed the following changes. Heart rate 72 +/- 15 beats per min (mean +/- SD) to 151 +/- 23; cardiac output 6.0 +/- 1 liter per min to 17.7 +/- 4.1; carbon monoxide diffusing capacity, 46 +/- 10 ml per min per Hg to 65 "/- 11. These all remained constant between 10- and 50-min exercise. The idQwl increased from 178 +/- 37 ml at rest to 219 +/- 46 ml at 10 min and 233 +/- 43 ml at 50 min, and pulmonary capillary blood volume increased from 140 +/- 52 ml at rest to 220 +/- 106 and 206 +/- 98 at 10 and 50 min of exercise, respectively. All of the changes from rest to early exercise were significant (P less than 0.05) by paired t test. There were no significant changes between early and late exercise. We concluded that the early exercise increase in idQwl was due to redistribution of blood flow among and within alveolar walls. The absence of any increase in idQwl between early and late exercise is evidence against accumulation of lung fluid.

Effect of increased vascular pressure on lung fluid balance in unanesthetized sheep.

In 20 unanesthetized sheep, we measured lung lymph flow and lymph and plasma protein concentrations during steady-state base-line conditions and during steady-state elevations of pulmonary microvascular hydrostatic pressure (range 3 to 23 cm H2O). In every sheep there was a base-line lung lymph flow (average 5.7 +/- 2.5 (SD) ml/hour), demonstrating that net fluid filtration occurred. The base-line lymph-plasma total protein ratio averaged 0.69 +/- 0.05, indicating a high protein osmotic pressure in the interstitial fluid at the filtration site. Lymph flow increased and lymph protein concentration decreased approximately linearly whenever hydrostatic pressure rose. A new steady-state condition was reached in 1-2 hours. The difference in plasma-to-lymph protein osmotic pressure increased by half the hydrostatic pressure increment (50% negative feedback regulation). Extravascular lung water content, measured post-mortem, did not change significantly until microvascular hydrostatic pressure more than doubled, indicating a large safety factor that protects the lungs against fluid accumulation normally. The major contributions to the safety factor appeared to be a sensitive and efficient lymph pump coupled to a washout of interstitial protein. The fluid filtration coefficient, whose calculation required many assumptions, averaged 1.64 +/- 2.65 ml/(cm H2O times hour) in the base-line condition and did not change significantly over the pressure range studied.