Biomedical subjects
Publications and source records attributed to J T Li.
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BACKGROUND: Skin testing is a common diagnostic tool in allergy. It is considered a safe procedure, although systemic reactions have been reported. OBJECTIVE: To identify the systemic reaction rates of allergy skin tests and to determine the clinical outcome of such reactions. METHOD: This retrospective study used a computerized database at the Mayo Clinic to identify patients who developed systemic reactions to skin tests. Altogether 497,656 skin tests were performed on 18,311 patients from January 1992 to June 1997. Skin puncture tests were performed on 16,505 patients. Skin puncture and intradermal skin tests were performed on 1,806 patients. Systemic reactions were evaluated and treated by physicians. RESULTS: There were 6 systemic reactions, an overall rate of 33 systemic reactions per 100,000 skin tests. All six patients had asthma. The systemic reaction rates for latex skin testing was 152 or 228 reactions per 100,000 latex skin tests, to penicillin and antibiotics 72 reactions per 100,000 penicillin and antibiotics skin tests, and to aeroallergens 15 or 23 reactions per 100,000 aeroallergen skin tests. The systemic reaction rate for skin puncture test was 30 reactions per 100,000 skin puncture tests, for skin puncture and intradermal skin tests, the rate was 55 reactions per 100,000 skin puncture and intradermal skin tests. All 6 patients were treated and dismissed within 1 hour after treatment. CONCLUSION: The systemic reaction rate to skin tests was very low. Systemic reactions were mild and all patients recovered fully within 1 hour.
BACKGROUND: There are few studies that examine referral patterns for asthma and few studies that examine the referring physicians' reasons for consultation. OBJECTIVE: The purpose of this study was to survey generalist physicians on their referral patterns for adult patients with asthma. METHODS: We mailed a questionnaire to all the staff (faculty) in the Department of Family Medicine and the Division of Community Internal Medicine at the Mayo Clinic in Rochester, Minnesota. There were 37 completed questionnaires (18 family medicine and 19 internal medicine) out of a total of 58 for a response rate of 64%. The survey asked what were reasons for consultation, whether allergists or pulmonologists were preferred, and the characteristics of a good consultation. RESULTS: We asked respondents to indicate "how often you consult a specialist for an adult asthma patient" for a variety of clinical indications. The percentage responding "always" (for the top five indications) were if the patient requests one (46%), for allergen immunotherapy (38%), for single life-threatening attack (27%), for allergy testing (14%), and for steroid-dependent asthma or poorly controlled asthma (11%). Twenty-seven percent of respondents generally consulted allergists only, 22% generally consulted pulmonologists only, 3% indicated both, while 46% had no preference. Respondents did express a preference for a pulmonologist when the reported reason for the consultation was diagnosis of asthma uncertain, chronic cough, asthma in smoker, exercise training, or for an allergist when the reported reason for consultation was allergy evaluation or immunotherapy. The respondents indicated that the top six characteristics of a good consultation were the following: clear recommendations, clinically appropriate recommendations, high patient satisfaction, including recommendations for future management scenarios, including educational content in the consultation, and calling the referring physician before requesting a secondary consultation. CONCLUSIONS: These results suggest that while consultation occurs often for severe or uncontrolled asthma, some asthma patients who may benefit from consultation may not be seeing the specialist. There were no systematic preferences for consultations with allergists versus pulmonologists for asthma although for some clinical indications pulmonologists or allergists were favored. Referring physicians value clear, clinically appropriate recommendations.
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Mesna is administered with ifosfamide and cyclophosphamide to reduce the incidence of hemorrhagic cystitis. In the present model of mesna metabolism and disposition, mesna is rapidly and irreversibly oxidized to dimesna in the plasma, passes unchanged through the liver, and is then reduced by the kidney and excreted. Our detection of a high ratio of mesna to dimesna in the plasma of clinical samples led us to reinvestigate the hepatic metabolism of mesna and dimesna. We perfused isolated rat livers from female Sprague Dawley rats with protein-free buffered solution containing dimesna at concentrations observed during therapy. In single-pass perfusions, each liver was perfused with up to three dimesna concentrations during consecutive 20-min periods. Recirculating perfusions were used to study single supratherapeutic concentrations of dimesna or mesna. Mesna and dimesna concentrations were measured by specific chromatographic procedures. Dimesna reduction, adjusted by the effluent flow rate and liver weight (0.4-58.5 nmol/min/g liver), correlated closely by linear regression (r = 0.98; n = 36) to the perfused dimesna concentration (4.2-249 microM), indicating a clearance of 0.20 ml/min/g liver. The concentration of dimesna that entered the liver closely matched the summed concentration of mesna and dimesna emerging in the effluent perfusate (single-pass experiments: slope, 0.98; intercept, -0.30; r = 1.00; n = 31). Only trace amounts of unidentified thiols were detected in the bile during recirculation of perfusates with 1 mM mesna or 250 microM dimesna. The effluent mesna concentration correlated inversely with the flow rate, which was consistent with a low extraction ratio in the perfusion model. These data suggested that the dimesna reduction rate was limited by hepatic uptake. Dimesna reduction was decreased by agents that deplete glutathione. Pretreatment of rats with up to 100 mg/kg ifosfamide did not impair hepatic dimesna reduction. In control experiments, dimesna was not reduced during recirculation through the apparatus without a liver. Mesna was oxidized to dimesna during oxygenation of the perfusate in the reservoir, but mesna injected directly into the perfusate just before entry into the liver passed unchanged into the effluent. Extrapolation of the dimesna clearance data from the perfusion model to humans suggests that hepatic dimesna reduction may counterbalance the rapid oxidation of mesna in plasma. The proposed equilibrium is consistent with clinical observations and suggests a new model for mesna metabolism and disposition.
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BACKGROUND: Inhaled corticosteroids and oral theophylline are effective treatments for moderate asthma. OBJECTIVE: We sought to compare the benefits and adverse reactions of theophylline and aerosol beclomethasone spray. METHODS: A multicenter, double-blind, double-placebo, randomized, controlled trial of 1-year duration was performed. Seven hundred forty-seven patients with asthma received either beclomethasone dipropionate aerosol spray (84 microg four times per day) or sustained-release theophylline twice per day in doses adjusted for optimum control of the disease. The main outcome measures were daily diary of symptoms and peak flow rates (recorded on a mark-sense computer-readable form); supplemental bronchodilator use; doctor's office or hospital visits and absence from work or school; spirometry; methacholine testing; adverse experiences; and cortisol blood measurements. RESULTS: Both treatment strategies reduced symptoms promptly and achieved low absenteeism from work or school and low rates of emergency treatment for asthma. Both maintained nearly normal pulmonary function. Beclomethasone was statistically significantly more effective in reducing symptoms, supplemental bronchodilator and systemic glucocorticoid doses, bronchial hyperresponsiveness, and eosinophilia. However, the magnitude of these differences was small. Theophylline caused more headache, nervousness, insomnia, and gastrointestinal distress, and more patients discontinued treatment because of side effects. Beclomethasone caused more oropharyngeal candidiases and hoarseness and reduced morning plasma cortisol levels before and after cosyntropin. It reduced the rate of growth in children. No new cataracts or glaucoma developed. CONCLUSION: Theophylline effectively controlled symptoms at lower than the customarily recommended blood level. The risk/ benefit profiles of these agents suggest that inhaled corticosteroids may be the preferred agent for most adult patients and for some children.
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This algorithm on the diagnosis and treatment of asthma is intended to complement and update the previously published Practice Parameters for the Diagnosis and Treatment of Asthma. Both documents were developed by the Joint Task Force on Practice Parameters, representing the AAAAI, ACAAI, and the JCAAI. The authors of this asthma algorithm have attempted to include all the elements essential for the diagnosis and care of patients with asthma. Every effort was made to keep the algorithm clear and concise, yet thorough and complete (Fig 1). Each component of the algorithm is elaborated further in a brief annotation. For further discussion, the reader is referred to the more extensive Practice Parameters for the Diagnosis and Treatment of Asthma.
The algorithm and text annotations in this document are intended to assist clinical decision making about patients who present with symptoms of rhinitis. This document complements the Executive Summary of Joint Task Force Practice Parameters for Diagnosis and Management of Rhinitis (Ann Allergy, Asthma, Immunol 1998; 81:463-468) and Diagnosis and Management of Rhinitis: Complete Guidelines of the Joint Task Force on Practice Parameters in Allergy, Asthma and Immunology (Ann Allergy, Asthma, Immunol 1998;81:478-578). The Joint Task Force on Practice Parameters in Allergy, Asthma and Immunology is co-sponsored by the American Academy of Allergy, Asthma and Immunology, the American College of Allergy, Asthma and Immunology and the Joint Council of Allergy, Asthma and Immunology.
This document contains complete guidelines for diagnosis and management of rhinitis developed by the Joint Task Force on Practice Parameters in Allergy, Asthma and Immunology, representing the American Academy of Allergy, Asthma and Immunology, the American College of Allergy, Asthma and Immunology and the Joint Council on Allergy, Asthma and Immunology. The guidelines are comprehensive and begin with statements on clinical characteristics and diagnosis of different forms of rhinitis (allergic, non-allergic, occupational rhinitis, hormonal rhinitis [pregnancy and hypothyroidism], drug-induced rhinitis, rhinitis from food ingestion), and other conditions that may be confused with rhinitis. Recommendations on patient evaluation discuss appropriate use of history, physical examination, and diagnostic testing, as well as unproven or inappropriate techniques that should not be used. Parameters on management include use of environmental control measures, pharmacologic therapy including recently introduced therapies and allergen immunotherapy. Because of the risks to patients and society from sedation and performance impairment caused by first generation antihistamines, second generation antihistamines that reduce or eliminate these side effects should usually be considered before first generation antihistamines for the treatment of allergic rhinitis. The document emphasizes the importance of rhinitis management for comorbid conditions (asthma, sinusitis, otitis media). Guidelines are also presented on special considerations in patients subsets (children, the elderly, pregnancy, athletes and patients with rhinitis medicamentosa); and when consultation with an allergist-immunologist should be considered.
In the presence of montmorillonite K 10, 5(6)-unsaturated sterols (1) were heated under ultrasound at 45 degrees C in dichloromethane for 2-5.5 h to provide 3 beta,3'beta-5(6)/5'(6')-unsaturated disteryl ethers (2) in 35-79% yield. Meanwhile, 3 alpha,3'alpha-diandrost-5-en-17-one-3-yl ether (3a) and 3 alpha,3'alpha-dipregn-5-en-20-one-3-yl ether (3b) were also obtained as by-products from 3 beta-hydroxyl-androst-5-en-17-one (1a) and 3 beta-hydroxyl-pregnan-5-en-20-one (1b) respectively.
PURPOSE: To compare the pharmacokinetics of the approved I.V. (intravenous) mesna regimen and an investigational I.V.-oral regimen that could be used in outpatients who receive ifosfamide. PATIENTS AND METHODS: The I.V. regimen consisted of three I.V. mesna doses given at 0, 4, and 8 hours after ifosfamide administration. The investigational regimen included an I.V. mesna dose given concurrently with ifosfamide, followed 2 and 8 hours later by oral administration of mesna tablets. I.V. and oral mesna doses equaled 20% and 40%, respectively, of the ifosfamide dose. The study subjects were 12 lung cancer patients who received ifosfamide 1.2 g/m2 daily for 5 days. The patients were randomized to receive either the I.V.-oral or I.V. mesna regimen on day 1, followed by crossover to the other regimen on days 2 through 5 of ifosfamide treatment. The urinary profiles of mesna and dimesna excretion were determined on days 1, 2, and 5; pharmacokinetic parameters for blood samples were determined only on day 5. RESULTS: During the first 12 hours after ifosfamide administration, the amount of mesna excreted and the profile of urinary mesna excretion was similar for both regimens; however, the I.V.-oral regimen showed less fluctuation in the excretion rate and higher trough values. During hours 12 to 24, about eightfold more mesna was excreted by patients given the I.V.-oral than the I.V. regimen. CONCLUSION: These pharmacokinetic data show that the I.V.-oral regimen should be at least as uroprotective as the I.V. mesna regimen. Patients may also benefit from the I.V.-oral regimen because of the higher trough values during hours 0 through 12 and the sustained urinary mesna excretion during hours 12 through 24.
Health-care advocacy extends beyond the understanding of environmental, social, and economic factors that affect health. Patient advocacy is more than a role--it is a principle that governs the patient-physician relationship and the practice of medicine. Physicians should be reminded that the healing power of medicine is not self-appointed. The authority of medicine derives from the principle of patient advocacy--that is, for 3,500 years society has identified, separated, and commissioned physicians for the sole purpose of providing care to sick and suffering patients. If we physicians compromise on patient advocacy, we will surely surrender this commission.
Although mesna has been used for more than a decade to reduce the incidence of hemorrhagic cystitis induced by ifosfamide and cyclophosphamide, the disposition of i.v. and oral mesna has not been adequately described. To obtain accurate bioavailability data for the design of mesna regimens, we developed procedures to preserve and measure mesna and dimesna in the blood and urine and studied 25 volunteer subjects who received single doses of i.v. mesna and four different formulations of oral mesna in a five-way randomized crossover study. The dose-adjusted area under the blood concentration-time curve showed no difference in bioavailability for i.v. and oral mesna; however, the maximum mesna concentration after oral doses was 16% of that estimated for i.v. doses. The short initial half-life of i.v. mesna indicated that mesna was rapidly cleared; however, the blood concentrations of mesna uniformly exceeded those of dimesna after oral as well as i.v. doses, which suggested that reduced mesna and oxidized mesna disulfide are in equilibrium. The ratio of mesna:dimesna was higher in protein-free plasma than it was in the urine, which suggested that most urinary mesna is produced by glomerular filtration of mesna rather than by renal tubular reduction of dimesna. The sum of mesna and dimesna excretion after the i.v. doses (73% of the dose) and the four oral formulations (68-73%) showed no difference in urinary bioavailability, consistent with the blood data. However, the urinary bioavailability of the therapeutically active free-thiol mesna was greater after i.v. doses (40% of the dose) than it was after oral doses (31-33%). The ratio of oral:i.v. mesna excretion ranged from 0.52-1.23 (mean, 0.82) among the 24 subjects. Urinary mesna concentrations exceeded 50 microM in all subjects for up to 12 h after oral doses as compared to 4 h after i.v. doses. About 90% of this mesna was excreted by hour 2 after i.v. doses and by hour 9 after oral doses. The mean maximum concentration of mesna in blood and excretion into urine were both 2.6 h after dosing. The oral formulations thus showed sustained urinary excretion, and their urinary bioavailability approached that of i.v. mesna.
BACKGROUND: Although oral and inhaled glucocorticoid therapy may impair growth in children with asthma, the effect of glucocorticoid therapy and asthma on attained adult height has not been extensively studied in representative children in the community. OBJECTIVES: The study was designed to compare the attained adult height of children with asthma with the attained adult height of nonasthmatic children and to compare the attained adult height of asthmatic children treated with glucocorticoids with the attained adult height of asthmatic children who did not receive glucocorticoids. METHODS: Residents of Rochester, Minnesota, with onset of asthma from 1964 to 1987 and age- and sex-matched non-asthmatic residents of Rochester were studied. Glucocorticoid exposure was assessed from medical records. The mean of 5 stadiometer measurements of adult height, adjusted for sex and parental height, was analyzed. RESULTS: One hundred fifty-three patients with asthma (mean age at onset, 6.1 +/- 4.8 years) and 153 age- and sex-matched nonasthmatic subjects were studied. Adult height of patients with asthma (mean age at measurement, 25.7 +/- 5.2 years) was not significantly different from the adult height of non-asthmatic subjects; the overall difference, adjusted for mid-parental height, was -0.20 cm (95% confidence interval from -0.27 to 1.64). The adult height of asthmatic children treated with glucocorticoids was not significantly different from the adult height of patients with asthma not treated with glucocorticoids; the difference after adjusting for mid-parental height was -0.2 cm (95% confidence interval from -0.1 to 0.6). CONCLUSIONS: We conclude that the attained adult height of patients with asthma is not different from the adult height of age- and sex-matched nonasthmatic subjects and that the attained adult height of asthmatic children treated with glucocorticoids is not significantly different from the adult height of children not treated with glucocorticoids.
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