The costs of atopy and asthma in children: Assessment of direct costs and their determinants in a birth cohort

The aim of this study was to estimate costs accrued by the health care of children with asthma in comparison to children with atopic eczema and seasonal rhinitis and to investigate cost determinants. From the multicenter cohort study (MAS-90), we selected children with an asthma, atopic eczema and/or seasonal rhinitis diagnosis during the first 8 years of life, and overall 8-year health care utilization was estimated retrospectively by reviewing medical records. Asthma treatment (n = 76) incurs an average cost of US$ 627 per year, 44% due to hospital stays. Atopic eczema treatment (n = 91) cost on average US$ 219 and seasonal rhinitis (n = 69) US$ 57 per year. In asthma and atopic eczema, costs increase significantly with disease severity. Allergy diagnostics use accounts for only 1% of total costs. Costs for asthma and atopic eczema treatment are highest in those years when topical steroids are used for the first time, but decrease with every further year of steroid use. A remarkable 25% of asthmatic children with severe symptoms were not treated according to national guidelines, so that most steroid treatment was initiated during the first hospital stay. In the case of asthma, total direct costs increased until the 3rd year of the disease, and then decreased with further years of diagnosis, while steroid use continued to increase. These results indicate a 'learning effect' in the treatment of asthma and atopic eczema for each patient as well as considerable cost-saving potential by preventing severe asthma. Moreover, the importance of considering cost-driving factors and using cohort or longitudinal designs in cost-of-illness approaches is emphasized.     

Comparison of Gadomer-17 and Gd-DTPA in image quality of contrast-enhanced MR angiographies using flow phantom model

The purpose of this study was to compare the image quality of 3D-TOF MR angiography (MRA) using Gadomer-17 with that using Gd-DTPA in a flow phantom model, and to present preliminary data about the proper dose concentration of Gadomer-17. In the visual analysis of vessel conspicuity, we compared the quality of pre- and post-contrast MIP images. For quantitative analysis, the signal intensities were measured in the axial base 3D-TOF images, and then the relative contrast enhancement was calculated. The results of our studies were that: 1. Maximal signal intensities were obtained at 1 mmol/L of Gadomer-17 and 4 mmol/L of Gd-DTPA. 2. Flow-related signal loss was decreased by Gd-DTPA proportional to the concentration, but Gadomer-17 did not show such a dose accumulative effect. In conclusion, after comparing the results of Gd-DTPA, it was clear that improved MRA images and higher signal intensities of vessels were obtained when lower concentrations of Gadomer-17 were used.     

Gas transport during high-frequency ventilation: Theoretical model and experimental validation

We present a theoretical model of gas transport through the dead space during high-frequency ventilation (HFV) with volumes less than dead space volume. The analysis is based on the axial distribution of transit times of gas moving through the dead space. The model predicts that for tidal volumes (V) much less than dead space (V_d), gas exchange will be proportional to the product of frequency (f) and V². If gas transport is analyzed in terms of Fick's law, then the effective diffusion coefficient (D_eff) can be shown to be equal to fV² times a constant, whose value equals the square of the coefficient of dispersion of axial transit times through the dead space . Experimental results in straight tubes fit the predictions of this model quite well. A through the entire dead space of about 30% is more than sufficient to account for gas exchange during HFV in physical models or in intact animals. An axial dispersion of this magnitude can be measured directly from a typical Fowler dead space determination in healthy subjects.     

Analysis of antibody response to the measles virus using synthetic peptides of the fusion protein Evidence of non-random pairing of T and B cell epitopes

The measles virus induces a life-long immune response associated with antibodies specific for the fusion protein. To map the linear immunodominant recognition sites of the fusion (F) protein of the measles virus, we have reacted a complete set of 108 overlapping pentadecapeptides with purified IgG obtained from donor sera with elevated anti-measles titers. The antibodies recognized about 20% of the peptides and generated a characteristic binding pattern, defining about 6 or 7 distinctive regions (31–75; 111–145; 151–165; 191–215; 271–320; 421–440; 481–530) which include the major hydrophobic segment (111–145) of the intersubunit region and the C-terminal Cys-cluster region. The binding sites were located in close proximity of the few experimentally defined T cell epitopes. This pairing of T and B cell epitopes was corroborated by computer-assisted T cell prediction. The significance of a non-random association of T and B cell epitopes for processing and presentation is discussed. It is speculated that in long-term immunity against measles (F protein), B cells of the same sIg specificity play an important role both as antigen presenting cells and as antibody producing cells. In contrast to human sera from late convalescent donors, mouse and rabbit MV antisera with high neutralizing titers as well as neutralizing MV-F specific monoclonal antibodies did not react with the peptides.     

Influenza vaccination and the risk of primary cardiac arrest

Influenza epidemics are associated with an excess of mortality not only from respiratory diseases but also from other causes, and cardiovascular mortality increases abruptly during influenza epidemics, with little evidence of a lag period. In a population-based case-control study, the authors examined whether influenza vaccination was associated with a reduced risk of out-of-hospital primary cardiac arrest (PCA), a major contributor to cardiovascular mortality in the community. Cases of PCA (n = 342) without prior heart disease or life-threatening comorbidity that occurred in King County, Washington, were identified from paramedic incident reports from October 1988 to July 1994. Demographically similar controls (n = 549) were identified from the community by using random digit dialing. Spouses of subjects were interviewed to assess treatment with influenza vaccine during the previous year and other risk factors. After adjustment for demographic, clinical, and behavioral risk factors, influenza vaccination was associated with a reduced risk of PCA (odds ratio = 0.51, 95 percent confidence interval: 0.33, 0.79). The authors suggest that while the association of influenza vaccination with a reduced risk of PCA is consistent with cohort studies of influenza vaccination and total mortality, further studies are needed to determine whether the observed association reflects protection or selection.     

Pulmonary artery catheterization and clinical outcomes: National Heart, Lung, and Blood Institute and Food and Drug Administration Workshop Report. Consensus Statement

Gordon R. Bernard, MD; George Sopko, MD; Frank Cerra, MD; Robert Demling, MD; Henry Edmunds, MD; Samuel Kaplan, MD; Larry Kessler, DSc; Henry Masur, MD; Polly Parsons, MD; Deborah Shure, MD; Carol Webb, RN, MSN, CCRN; Herbert Wiedemann, MD; Gail Weinmann, MD; David Williams, MD

JAMA. 2000;283:2568-2572.

Objective  The efficacy and safety of the pulmonary artery catheter are under scrutiny because of its association with increased morbidity and mortality in observational studies. In response, the National Heart, Lung, and Blood Institute (NHLBI) and the US Food and Drug Administration (FDA) conducted the Pulmonary Artery Catheterization and Clinical Outcomes workshop in Alexandria, Va, on August 25 and 26, 1997, to develop recommendations regarding actions to improve pulmonary artery catheter utility and safety.

Participants  The NHLBI and FDA planning task force selected a workshop chairperson, subcommittee chairs, and participants. Approximately 85 participants were selected for their collective expertise in critical care, pulmonary medicine, cardiovascular medicine and surgery, pediatrics, nursing, biostatistics, and medical economics. The meeting was open to industry representatives and other government and lay observers. This workshop was funded by the NHLBI and the FDA's Division of Devices.

Evidence  Published reports relating to the efficacy and safety of the pulmonary artery catheter, especially consensus documents developed by professional societies.

Consensus Process  The planning task force disseminated materials, held teleconferences, and developed draft position papers prior to the workshop. These were modified during the workshop and thereafter in the course of several teleconferences, and presented to the entire group for final modifications and approval.

Conclusions  A need exists for collaborative education of physicians and nurses in performing, obtaining, and interpreting information from the use of pulmonary artery catheters. This effort should be led by professional societies, in collaboration with federal agencies, with the purpose of developing and disseminating standardized educational programs. Areas given high priority for clinical trials were pulmonary artery catheter use in persistent/refractory congestive heart failure, acute respiratory distress syndrome, severe sepsis and septic shock, and low-risk coronary artery bypass graft surgery.

     

Dynamic contrast-enhanced MR imaging of bacterial abscess and VX2 carcinoma in rabbits: comparison of gadopentetate dimeglumine and a macromolecular contrast agent

OBJECTIVE: The objective of this study was to compare enhancement patterns of a blood-pool contrast agent, Gadomer-17, with those of gadopentetate dimeglumine in bacterial abscesses and VX2 carcinoma in rabbits. MATERIALS AND METHODS: Fourteen rabbits with experimentally induced bacterial abscesses and VX2 carcinoma in both thighs underwent dynamic contrast-enhanced MR imaging with Gadomer-17 and gadopentetate dimeglumine at a 24-hr interval. The enhancement ratios (postcontrast to precontrast signal intensities) of lesions in the same animal were assessed and correlated with microvessel density. RESULTS: For Gadomer-17, the enhancement ratio of the abscesses (1.66 +/- 0.39) peaked 15 min after the injection, while that of the carcinoma (2.05 +/- 0.16) peaked at 10 min. The enhancement ratios of the carcinoma were consistently higher than those of the abscesses up to 30 min. For gadopentetate dimeglumine, peak enhancement ratio of the abscesses (2.30 +/- 0.75) was seen 5 min after the injection, while that of the carcinoma (2.32 +/- 0.51) was seen at 3 min. The enhancement ratios of the carcinomas were significantly higher at 1 min, but significantly lower at 20-30 min, compared with those of the abscesses, as a result of rapid decrease of enhancement ratios in the carcinomas. The microvessel density was 9.8 +/- 5.2 vessels per field of view for the abscesses and 36.3 +/- 9.5 vessels per field of view for the carcinoma (p < 0.001). CONCLUSION: Delayed peak enhancement and slow decay were found in both bacterial abscess and VX2 carcinoma with Gadomer-17, whereas early peak enhancement and rapid decay were found especially in VX2 carcinoma with gadopentetate dimeglumine. Enhancement ratios on MR imaging with a blood-pool contrast agent correlated well with the microvessel density in bacterial abscess and VX2 carcinoma.     

Automated solid-phase extraction and two-step derivatisation for simultaneous analysis of basic illicit drugs in serum by GC/MS

A combination of automated solid-phase extraction (SPE) and subsequent two-step derivatisation has been developed for the simultaneous analysis of basic drugs of abuse and cocaine metabolites in serum samples. Substances included in this procedure are morphine, codeine, methadone, cocaine, benzoylecgonine, methylecgonine, amphetamine, methamphetamine, MDMA, MDEA and MDA. SPE with mixed-mode cartridges (RP-C8 and cation-exchange) was fully automated with a Zymark RapidTrace SPE robot. GC/MS analysis was performed after derivatisation with a new two-step reaction by trifluoroacetic anhydride and 2,2,3,3,3-pentafluoropropanol. High recoveries (> 85%) with high reproducibility (CV 1.1-3.8%) were found for all drugs. High correlation coefficients (r > 0.998) were obtained due to the addition of deuterated standards prior to extraction. Experience obtained over 2 years of applying this method to drug analysis in serum is discussed.