Improvement of cardiac functions by chronic metformin treatment is associated with enhanced cardiac autophagy in diabetic OVE26 mice

OBJECTIVE

Autophagy is a critical cellular system for removal of aggregated proteins and damaged organelles. Although dysregulated autophagy is implicated in the development of heart failure, the role of autophagy in the development of diabetic cardiomyopathy has not been studied. We investigated whether chronic activation of the AMP-activated protein kinase (AMPK) by metformin restores cardiac function and cardiomyocyte autophagy in OVE26 diabetic mice.

RESEARCH DESIGN AND METHODS

OVE26 mice and cardiac-specific AMPK dominant negative transgenic (DN)-AMPK diabetic mice were treated with metformin or vehicle for 4 months, and cardiac autophagy, cardiac functions, and cardiomyocyte apoptosis were monitored.

RESULTS

Compared with control mice, diabetic OVE26 mice exhibited a significant reduction of AMPK activity in parallel with reduced cardiomyocyte autophagy and cardiac dysfunction in vivo and in isolated hearts. Furthermore, diabetic OVE26 mouse hearts exhibited aggregation of chaotically distributed mitochondria between poorly organized myofibrils and increased polyubiquitinated protein and apoptosis. Inhibition of AMPK by overexpression of a cardiac-specific DN-AMPK gene reduced cardiomyocyte autophagy, exacerbated cardiac dysfunctions, and increased mortality in diabetic mice. Finally, chronic metformin therapy significantly enhanced autophagic activity and preserved cardiac functions in diabetic OVE26 mice but not in DN-AMPK diabetic mice.

CONCLUSIONS

Decreased AMPK activity and subsequent reduction in cardiac autophagy are important events in the development of diabetic cardiomyopathy. Chronic AMPK activation by metformin prevents cardiomyopathy by upregulating autophagy activity in diabetic OVE26 mice. Thus, stimulation of AMPK may represent a novel approach to treat diabetic cardiomyopathy.

Understanding Structure−Stability Relationships ofCandidaantarticaLipase B in Ionic Liquids

Two different water-immiscible ionic liquids (ILs), 1-ethyl-3-methylimidizolium bis(trifluoromethylsulfonyl)imide and butyltrimethylammonium bis(trifluoromethylsulfonyl)imide, were used for butyl butyrate synthesis from vinyl butyrate catalyzed by Candida antarctica lipase B (CALB) at 2% (v/v) water content and 50 degrees C. Both the synthetic activity and stability of the enzyme in these ILs were enhanced as compared to those in hexane. Circular dichroism and intrinsic fluorescence spectroscopic techniques have been used over a period of 4 days to determine structural changes in the enzyme associated with differences in its stability for each assayed medium. CALB showed a loss in residual activity higher than 75% after 4 days of incubation in both water and hexane media at 50 degrees C, being related to great changes in both alpha-helix and beta-strand secondary structures. The stabilization of CALB, which was observed in the two ILs studied, was associated with both the maintenance of the 50% of initial alpha-helix content and the enhancement of beta-strands. Furthermore, intrinsic fluorescence studies clearly showed how a classical enzyme unfolding was occurring with time in both water and hexane media. However, the structural changes associated with the incubation of the enzyme in both ILs might be attributed to a compact and active enzyme conformation, resulting in an enhancement of the stability in these nonaqueous environments.

Stabilization of alpha-chymotrypsin by ionic liquids in transesterification reactions

Five different ionic liquids, based on dialkylimidazolium and quaternary ammonium cations associated with perfluorinated and bis (trifluoromethyl) sulfonyl amide anions, were used as reaction media to synthesize N-acetyl-L-tyrosine propyl ester by transesterification with alpha-chymotrypsin at 2% (v/v) water content at 50 degrees C. The synthetic activity was reduced by the increase in alkyl chains length of cations and by increases in anion size, which was related to the decrease in polarity. Incubation of the enzyme (with and without substrate) in ionic liquids exhibited first-order deactivation kinetics at 50 degrees C, allowing determination of deactivation rate constants and half-life times (1-3 h). Ionic liquids showed a clear relative stabilization effect on the enzyme, which was improved by increased chain length of the alkyl substituents on the imidazolium ring cations and the anion size. This effect was 10-times enhanced by the presence of substrate. For example, 1-butyl-3-methylimidazolium hexafluorophosphate increased the alpha-chymotrypsin half-life by 200 times in the presence of substrate with respect to the 1-propanol medium. These results show that ionic liquids are excellent enzyme-stabilizing agents and reaction media for clean biocatalysis in non-conventional conditions.

Continuous green biocatalytic processes using ionic liquids and supercritical carbon dioxide

Soluble Candida antarctica lipase B dissolved in ionic liquids showed good synthetic activity, enantioselectivity and operational stability in supercritical carbon dioxide for both butyl butyrate synthesis and the kinetic resolution of 1-phenylethanol processes by transesterification.

Impact of inhaled antiinflammatory therapy on hospitalization and emergency department visits for children with asthma

OBJECTIVE

Although the efficacy of inhaled antiinflammatory therapy in improving symptoms and lung function in childhood asthma has been shown in clinical trials, the effectiveness of these medications in real-world practice settings in reducing acute health care use has not been well-evaluated. This study examined the effect of inhaled antiinflammatory therapy on hospitalizations and emergency department (ED) visits by children for asthma.

DESIGN

Defined population cohort study over 1 year. Setting. Three managed care organizations (MCOs) in Seattle, Boston, and Chicago participating in the Pediatric Asthma Care-Patient Outcome Research and Treatment II trial. Participants. All 11 195 children, between 3 to 15 years old, with a diagnosis of asthma who were enrolled in the 3 MCOs between July 1996 and June 1997.

OUTCOME MEASURES

We identified children with 1 or more asthma diagnoses using automated encounter data. Medication dispensings were identified from automated pharmacy data. Multivariate logistic regression analysis was used to calculate effects of inhaled antiinflammatory therapy on the adjusted relative risk (RR) for hospitalization and ED visits for asthma.

RESULTS

Over 12 months, 217 (1.9%) of children had an asthma hospitalization, and 757 (6.8%) had an ED visit. After adjustment for age, gender, MCO, and reliever dispensing, compared with children who did not receive controllers, the adjusted RRs for an ED visit were: children with any (>/=1) dispensing of cromolyn, 0.4 (95% confidence interval [CI]: 0.3, 0.5); any inhaled corticosteroid (ICS), 0.5 (95% CI: 0.4, 0.6); any cromolyn or ICS combined (any controller), 0.4 (95% CI: 0.3, 0.5). For hospitalization, the adjusted RR for cromolyn was 0.6 (95% CI: 0.4, 0.9), for ICS 0.4 (95% CI: 0.3, 0.7), and for any controller 0.4 (95% CI: 0.3, 0.6). A significant protective effect for both events was seen among children with 1 to 5 and with >5 antiinflammatory dispensings. When the analysis was stratified by frequency of reliever dispensing, there was a significant protective effect for controllers on ED visits for children with 1 to 5 and with >5 reliever dispensings and on the risk of hospitalization for children with >5 reliever dispensings.

CONCLUSIONS

Inhaled antiinflammatory therapy is associated with a significant protective effect on the risk for hospitalization and ED visits in children with asthma. Cromolyn and ICSs were associated with similar effects on risks.asthma drug therapy, inhaled antiinflammatory agents, health maintenance organizations, hospitalization, emergency department.

The economic burden of asthma in US children: estimates from the National Medical Expenditure Survey

BACKGROUND

Asthma is the leading chronic illness of childhood, is responsible for substantial pediatric morbidity, and has a significant impact on use of health resources.

OBJECTIVE

Our purpose was to assess the per capita impact of pediatric asthma on medical care utilization and total expenditures.

METHODS

A population-based national probability survey, the National Medical Expenditure Survey, was conducted in 1987 to determine the use and cost of health care services in the United States. We analyzed the responses for all children aged 1 to 17 years with (n = 667) and without (n = 6911) asthma. Children with asthma were identified with use of a population-based screening question. Frequency and cost of medications, ambulatory visits, emergency department care, and hospitalizations for all reasons, including asthma, were assessed.

RESULTS

The period prevalence of childhood asthma in 1987 was 8.8% and the treated prevalence (any asthma medications) was 4.0%. Forty-one percent of families with asthmatic children were classified as having no primary insurance. Children with asthma used substantially more services in all categories of care: 3.1 times as many prescriptions, 1.9 times as many ambulatory provider visits, 2. 2 times as many emergency department visits, and 3.5 times as many hospitalizations. Only 10.7% of children with asthma were defined as chronic users of medications. Children with asthma incurred an average of $1129 (SD $5310) per child per year in total health care expenditures compared with $468 (SD $2960) for children without asthma, a 2.8-fold difference.

CONCLUSION

Asthma has considerable impact on the use and costs of medical care services among US children. Data from the 1987 National Medical Expenditure Survey provide a useful baseline against which more recent, postguideline data should be compared.

Utilization and cost of health care services for children with attention-deficit/hyperactivity disorder

BACKGROUND

Despite an increasing prevalence of diagnosed attention-deficit/hyperactivity disorder (ADHD) among children, the impact of ADHD on utilization and costs of health care services is largely unknown.

OBJECTIVE

To examine differences in health care utilization and costs between children with and without ADHD.

DESIGN

Retrospective matched cohort study conducted from January 1 to December 31, 1997. Setting. Health maintenance organization in western Washington State.

PARTICIPANTS

Children aged 3 through 17 years who were continuously enrolled in the health maintenance organization and used services during 1997 were eligible. Children were identified with ADHD if they had a diagnosis of ADHD or a prescription for a stimulant medication using automated patient files. Children without ADHD were randomly selected as controls and matched 4:1 to children with ADHD on age and sex.

OUTCOME MEASURE

Utilization and costs of specific categories of health care services. Results. A total of 2992 children (5.2%) were identified with ADHD. Children with ADHD incurred significantly greater per capita total costs ($1465 vs $690) than children without ADHD. Children with ADHD had 9.9 times more outpatient mental health visits (1.35/year vs 0.14/year), 3.4 times more pharmacy fills (11.25/year vs 3.30/year), and 1.6 times more primary care visits (3.84/year vs 2.36/year) than children without ADHD. The adjusted incremental costs were estimated to be $375 (95% confidence interval: $336-$416) for children with ADHD alone and $812 (95% confidence interval: $671-$973) for children with ADHD plus coexisting mental health disorders.

CONCLUSIONS

Children with ADHD use significantly more health care resources and incur significantly higher costs than children without ADHD. Coexisting mental health disorders substantially increase the cost of treating ADHD. Resource allocation decisions should consider the contributions of primary care, outpatient mental health, and pharmacy costs to the overall costs of care for children with ADHD.

Predictors of hemolytic uremic syndrome in children during a large outbreak of Escherichia coli O157:H7 infections

OBJECTIVE

To evaluate risk factors for progression of Escherichia coli O157:H7 infection to the hemolytic uremic syndrome (HUS).

STUDY DESIGN

We conducted a retrospective cohort study among 278 Washington State children <16 years old who developed symptomatic culture-confirmed E coli O157:H7 infection during a large 1993 outbreak. The purpose of the study was to determine the relative risk (RR) of developing HUS according to demographic characteristics, symptoms, laboratory test results, and medication use in the first 3 days of illness.

RESULTS

Thirty-seven (14%) children developed HUS. In univariate analysis, no associations were observed between HUS risk and any demographic characteristic, the presence of bloody diarrhea or of fever, or medication use. In multivariate analysis, HUS risk was associated with, in the first 3 days of illness, use of antimotility agents (odds ratio [OR] = 2.9; 95% confidence interval [CI] 1.2-7.5) and, among children <5.5 years old, vomiting (OR = 4. 2; 95% CI 1.4-12.7). Among the 128 children tested, those whose white blood cell (WBC) count was >/=13 000/microL in the first 3 days of illness had a 7-fold increased risk of developing HUS (RR 7. 2; 95% CI 2.8-18.5). Thirteen (38%) of the 34 patients with a WBC count >/=13 000/microL developed HUS, but only 5 (5%) of the 94 children whose initial WBC count was <13 000/microL progressed to HUS. Among children who did not develop HUS, use of antimotility agents in the first 3 days of illness was associated with longer duration of bloody diarrhea.

CONCLUSIONS

Prospective studies are needed to further evaluate measures to prevent the progression of E coli O157:H7 infection to HUS and to assess further clinical and laboratory risk factors. These data argue against the use of antimotility agents in acute childhood diarrhea. Our finding that no intervention decreased HUS risk underscores the importance of preventing E coli O157:H7 infections.

Fluorescence and CD spectroscopic analysis of the ?-chymotrypsin stabilization by the ionic liquid, 1-ethyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]amide

The stability of alpha-chymotrypsin in the ionic liquid, 1-ethyl-3-methyl-imidizolium bis[(trifluoromethyl)sulfonyl]amide ([emim][NTf2]), was studied at 30 and 50 degrees C and compared with the stability in other liquid media, such as water, 3 M sorbitol, and 1-propanol. The kinetic analysis of the enzyme stability pointed to the clear denaturative effect of 1-propanol, while both 3M sorbitol and [emim][NTf2] displayed a strong stabilizing power. For the first time, it is shown that enzyme stabilization by ionic liquids seems to be related to the associated structural changes of the protein that can be observed by differential scanning calorimetry (DSC) and fluorescence and circular dichroism (CD). The [emim][NTf2] enhanced both the melting temperature and heat capacity of the enzyme compared to the other media assayed. The fluorescence spectra clearly showed the ability of [emim][NTf2] to compact the native structural conformation of alpha-chymotrypsin, preventing the usual thermal unfolding which occurs in other media. Changes in the secondary structure of this beta/beta protein, as quantified by the CD spectra, pointed to the great enhancement (up 40% with respect to that in water) of beta-strands in the presence of the ionic liquid, which reflects its stabilization power.

Lipase catalysis in ionic liquids and supercritical carbon dioxide at 150 degrees C

Free and immobilized Candida antarctica lipase B dispersed in ionic liquids (1-ethyl-3-methylimidazolium bistriflimide and 1-buthyl-3-methylimidazolium bistriflimide) were used as catalyst for the continuous kinetic resolution of rac-1-phenylethanol in supercritical carbon dioxide at 120 and 150 degrees C and 10 MPa. Excellent activity, stability and enantioselectivity levels were recorded in continuous operation.

Hyperglycemia and Oxidative Stress: An Integral, Updated and Critical Overview of Their Metabolic Interconnections

This review focuses on the multiple and reciprocal relationships that exist between oxidative stress, hyperglycemia and diabetes and related metabolic disorders. Human metabolism uses most of the consumed glucose under aerobic conditions. Oxygen is needed in the mitochondria to obtain energy, as well as for the action of microsomal oxidases and cytosolic pro-oxidant enzymes. This relentlessly generates a certain amount of reactive oxygen species (ROS). Although ROS are intracellular signals necessary for some physiological processes, their accumulation leads to oxidative stress, hyperglycemia, and progressive resistance to insulin. A cellular pro-oxidant versus an antioxidant equilibrium would regulate ROS levels, but oxidative stress, hyperglycemia, and pro-inflammatory conditions feed back to each other and the relevance of the interconnections tends to increase those conditions. Hyperglycemia promotes collateral glucose metabolism through protein kinase C, polyols and hexosamine routes. In addition, it also facilitates spontaneous glucose auto-oxidation and the formation of advanced glycation end products (AGEs), which in turn interact with their receptors (RAGE). The mentioned processes undermine cellular structures, finally giving place to a progressively greater degree of oxidative stress with further hyperglycemia, metabolic alterations, and diabetes complications. NFκB is the major transcription factor involved in the expression of most of the pro-oxidant mediators, while Nrf2 is the major transcription factor regulating the antioxidant response. FoxO is also involved in the equilibrium, but its role is controversial. This review summarizes the key factors linking the diverse glucose metabolic routes enhanced in hyperglycemia with ROS formation and vice versa, emphasizing the role of the major transcription factors involved in the desirable balance between pro-oxidant and antioxidant proteins.

Chronic care costs in managed care

This DataWatch presents estimates of the health care costs for all adults who were continuously enrolled in a large staff-model health maintenance organization (HMO) during 1992. More than one-third of these adults were diagnosed with at least one chronic condition in 1992, and costs for this population are at least twice those of the population without chronic conditions. A diagnosis of a chronic condition results in an expected increase in costs of 80 percent-300 percent, depending on age, sex, and chronic condition profile. Previous studies of the costs of chronic illness have focused on the fee-for-service sector. As managed care continues to grow, it is important that economic analyses focus on this market segment.

Health care utilization and cost among children with asthma who were enrolled in a health maintenance organization

OBJECTIVE

To measure the impact of asthma on the use and cost of health care by children in a managed care organization.

DESIGN

Population-based historical cohort study.

SETTING

A medium-sized staff model health maintenance organization in western Washington state.

SUBJECTS

All 71 818 children, between age 1 to 17 years, who were enrolled and used services during 1992.

OUTCOME MEASURES

Children were identified with one or more asthma diagnoses during 1992 using automated encounter data. Nonurgent outpatient visits, pharmacy fills, urgent care visits, and hospital days, as well as associated costs were measured. All services were categorized as asthma care or nonasthma care. Multivariate regression analysis was used to compute marginal cost for asthma (difference in total cost between children with asthma and other children using services, adjusted for covariates).

RESULTS

Treated prevalence of asthma was 4.9%. Children with asthma incurred 88% more costs ($1060.32 vs $563. 81/yr), filled 2.77 times as many prescriptions (11.59 vs 4.19/yr), made 65% more nonurgent outpatient visits (5.75 vs 3.48/yr), and had twice as many inpatient days (.23 vs .11/yr) compared with the general population of children using services. Asthma care represented 37% of all health care received by children with asthma, while the remaining 63% were for nonasthma services. Almost two-thirds of asthma-related costs were attributable to nonurgent outpatient care and prescriptions; only one third was attributable to urgent care and hospitalizations. Controlling for age, sex, and comorbidities, the marginal cost of asthma was $615.17/yr (95% confidence interval $502.73, $727.61), which includes asthma as well as nonasthma services. This marginal cost represents 58% of all health care costs for children with asthma.

CONCLUSIONS

Children with asthma use significantly more health services (and incur significantly more costs) than other children using services, attributable largely to asthma care. The majority of all health care costs for children with asthma were for nonasthma services. Urgent care visits and hospitalizations are less important components of asthma costs in this managed care organization than has been found in other national studies.

Coronary slow flow phenomenon and risk for sudden cardiac death due to ventricular arrhythmias: a case report and review of literature

We report a case of coronary slow flow phenomenon (CSFP) in a patient who underwent coronary angiography due to anginal chest pain and recurrent syncope with complete normalization of flow after intracoronary adenosine. He was noted to have multiple episodes of nonsustained ventricular tachycardia on holter monitor and increased QTc dispersion on surface electrocardiogram (EKG). He responded very well to oral dipyridamole therapy with complete resolution of his symptoms and no episodes of ventricular tachycardia on the event recorder at 3 months. We review the diagnosis and clinical features of CSFP and its association with increased QTc dispersion and the role of oral dipyridamole therapy in this condition.

Criteria to Design Green Enzymatic Processes in Ionic Liquid/Supercritical Carbon Dioxide Systems

Five different ionic liquids (ILs) based on quaternary ammonium cations, with functional side chains ((3-hydroxypropyl)-trimethyl-, (3-cyanopropyl)-trimethyl-, butyl-trimethyl-, (5-cyanopentyl)-trimethyl- and hexyl-trimethyl-) associated with the same anion (bis(trifluoromethane)sulfonyl amide)), were synthesized, and their suitability for Candida antarctica lipase B (CALB)-catalyzed ester synthesis in IL/supercritical carbon dioxide (scCO(2)) biphasic systems was assayed. Catalytic efficiency of the system has been analyzed as a function of both enzyme properties and mass-transfer phenomena criteria. First, the suitability of these ILs as enzymic reaction media was tested for the kinetic resolution of rac-phenylethanol. All ILs were found to be suitable media for enzyme catalysis, the best catalytic parameter (5.3 U/mg specific activity, 94.9% selectivity) being obtained for the (5-cyanopentyl)-trimethylammonium. Second, enzyme stability in all of the ILs was studied at 50 degrees C over a period of 50 days, and data were analyzed by a two-step kinetic deactivation model. All of the ILs were shown to act as stabilizing agents with respect to hexane, producing an increase in the free energy of deactivation (to 25 kJ/mol protein) and an improvement in the half-life time of the enzyme (2000-fold), which agrees with the observed increased hydrophobicity of the cation alkyl side chain (measured by Hansen's solubility parameter, delta). By using two different CALB-IL systems with different hydrophobicity in the cation, continuous processes to synthesize six different short chain alkyl esters (butyl acetate, butyl propionate, butyl butyrate, hexyl propionate, hexyl butyrate, and octyl propionate) in scCO(2) at 10 MPa and 50 degrees C were carried out. Both rate-limiting parameters (synthetic activity and scCO(2)-ILs mass-transfer phenomena) were related with the delta-parameter of the ILs-alkyl chain and reagents.

Has asthma medication use in children become more frequent, more appropriate, or both?

OBJECTIVE

Despite national initiatives to improve asthma medical treatment, the appropriateness of physician prescribing for children with asthma remains unknown. This study measures trends and recent patterns in the pediatric use of medications approved for reversible obstructive airway disease (asthma medications).

DESIGN

Population-based longitudinal and cross-sectional analyses. Setting. A nonprofit staff model health maintenance organization located in the Puget Sound area of Washington state.

PARTICIPANTS

Children 0 to 17 years of age enrolled continuously during any one of the years from 1984 to 1993 (N = 83 232 in 1993). PRIMARY OUTCOME MEASURES. Percent of enrollees filling prescriptions for asthma medications and fill rates by medication class and estimated duration of inhaled antiinflammatory medication use.

RESULTS

Between 1984 and 1993, the frequency of asthma medication use increased: the percent of children filling any asthma medication prescription increased from 4. 0% to 8.1%, whereas the percent filling an inhaled antiinflammatory inhaler rose from 0.4% to 2.4%. In contrast, the intensity of inhaled antiinflammatory use decreased among users; 37% of users filled more than two inhalers during the year in 1984, and 29% in 1993. In high beta-agonist users (filling more than two beta-agonist inhalers each quarter per year), the estimated duration of inhaled antiinflammatory use increased slightly from a mean of 4.1 months per year in 1984-1986 to 5.0 months in 1991-1993; estimated duration of use in adolescents 10 to 17 years of age was approximately half that of children 5 to 9 years of age.

CONCLUSIONS

The proportion of children using asthma medications increased substantially during the study period, but the use of inhaled antiinflammatory medication per patient remained low even for those using large amounts of inhaled beta-agonists. These findings suggest that most asthma medications were used by children with mild lower airway symptoms and that inhaled antiinflammatory medication use in children with more severe disease fell short of national guidelines.

Effect of polyols on alpha-chymotrypsin thermostability: a mechanistic analysis of the enzyme stabilization

The influence of the synthetic substrate (N-acetyl-L-tyrosine ethyl ester) and the different polyols (ethylene glycol, glycerol, erythritol, xylitol and sorbitol) on the thermostability of alpha-chymotrypsin at 60 degrees C have been studied. The results obtained showed an important stabilizing effect in the presence of both additives. In order to describe the kinetics of enzyme stabilization, the experimental results were analyzed by a four-parameters deactivation model with excellent agreement. In all cases, alpha-chymotrypsin exhibited non-first-order deactivation kinetics, corresponding to a two-step unimolecular mechanism, where the main protective effect of polyols was observed in the first-step of the deactivation profile. Thus, the presence of polyols increased the level of activity stabilization (alpha 1), and decreased the first-order deactivation rate constant (k1). Additionally, the experimental results were analyzed as a function of both, the change in the standard free energy of denaturation (delta(delta Gzero)), and a protective effect, defined as the ratio of alpha-chymotrypsin half-lives (with and without polyols), showing in both cases a clear stabilizing effect of these polyhydroxylic cosolvents for the enzyme. The overall protective effect of polyols was also simultaneously related to their concentration and their water-activity depressing power.

One-year experience with an inpatient asthma clinical pathway

OBJECTIVE

To study the effects of an inpatient asthma clinical pathway on the processes and outcomes for children who were admitted to a hospital for the treatment of asthma.

DESIGN

Before-and-after study.

SETTING

A private nonprofit academic children's hospital in Seattle, Wash.

PATIENTS AND METHODS

Three hundred forty-two admissions of 297 patients in the first year of the asthma clinical pathway were compared with 353 admissions of 292 similar patients in the previous year. Patients who required intensive care, were younger than 2 years, or had a major chronic disease were excluded.

INTERVENTION

Asthma was chosen for the development of a clinical pathway because of its large number of admissions, involvement of multiple health care providers (nurses, physicians, and respiratory therapists), predictable hospital course, and variable lengths of hospital stay. The pathway was a consensus-based guideline for patient management that was intended to be adapted to the care of an individual patient. Prior to the implementation of the clinical pathway, nurses, attending physicians, house staff, and respiratory therapists were trained in its use. The main hospital chart of each patient who was admitted to the pathway had a flowchart that outlined day-to-day guidelines for monitoring and care. Nursing staff were responsible for documenting when a patient's care varied from the pathway, and these variances were entered into a computer database.

OUTCOME MEASURES

Use of peak flowmeters, steroids, laboratory studies, radiological studies, and respiratory therapy was assessed by analyzing the patients' electronic billing records. For patients enrolled in the pathway, additional data on process of care were obtained by analyzing the variance database. For both groups, the total charges, length of stay, and rate of readmission to the hospital were measured by use of the billing records.

RESULTS

There were no significant differences in the use of steroids or peak flowmeters, average lengths of stay, or total charges between the 2 groups. However, patients in the "pathway group" had significantly lower average charges for laboratory ($26 vs $39; P < .05) and radiology ($32 vs $55; P < .001) services. Variances from the pathway guidelines were most often related to the patients' responses to therapy.

CONCLUSIONS

The asthma clinical pathway had no effect on clinical outcomes and small effects on the use of resources. Further development, including physician and nurse training, computer and administrative support, and clinical severity scales, are needed to develop the potential utility of the clinical pathway as a research and quality assurance tool.

A non-destructive method to determine the safranal content of saffron (Crocus sativus L.) by supercritical carbon dioxide extraction combined with high-performance liquid chromatography and gas chromatography

A supercritical carbon dioxide extraction method to obtain selectively volatile compounds of saffron without sample destruction has been developed. The influence of both pressure and temperature was studied, 20 MPa and 100 degrees C being the best conditions to extract the total safranal content. A decrease in supercritical fluid density was shown to be a critical parameter for enhancing the extraction power of carbon dioxide. For all the assay conditions, the extracts mainly contained safranal and HTCC, as demonstrated by gas chromatography and high-performance liquid chromatography analyses. Both chromatographic methods were suitable for safranal quantification and showed excellent agreement. Supercritical extracts from five different saffron types were studied by high-performance liquid chromatography and their safranal contents were determined.