Correction: Weight Gain Prevention Outcomes From a Pragmatic Digital Health Intervention With Community Health Center Patients: Randomized Controlled Trial

[This corrects the article DOI: 10.2196/50330.].

Weight Gain Prevention Outcomes From a Pragmatic Digital Health Intervention With Community Health Center Patients: Randomized Controlled Trial

BACKGROUND

The prevalence of obesity and its associated comorbidities continue to rise in the United States. Populations who are uninsured and from racial and ethnic minority groups continue to be disproportionately affected. These populations also experience fewer clinically meaningful outcomes in most weight loss trials. Weight gain prevention presents a useful strategy for individuals who experience barriers to weight loss. Given the often-limited weight management resources available to patients in primary care settings serving vulnerable patients, evaluating interventions with pragmatic designs may help inform the design of comprehensive obesity care delivered in primary care.

OBJECTIVE

This study aims to evaluate the effectiveness of Balance, a 2-arm, 12-month pragmatic randomized controlled trial of a digital weight gain prevention intervention, delivered to patients receiving primary care within federally qualified community health centers.

METHODS

Balance was a 2-arm, 12-month pragmatic randomized controlled trial of a digital weight gain prevention intervention delivered to individuals who had a BMI of 25-40 kg/m2, spoke English or Spanish, and were receiving primary care within a network of federally qualified community health centers in North Carolina. The Balance intervention was designed to encourage behavioral changes that result in a slight energy deficit. Intervention participants received tailored goal setting and tracking, skills training, self-monitoring, and responsive health coaching from registered dietitians. Weight was measured at regular primary care visits and documented in the electronic health record. We compared the percentage of ≤3% weight gain in each arm at 24 months after randomization-our primary outcome-using individual empirical best linear unbiased predictors from the linear mixed-effects model. We used individual empirical best linear unbiased predictors from participants with at least 1 electronic health record weight documented within a 6-month window centered on the 24-month time point.

RESULTS

We randomized 443 participants, of which 223 (50.3%) participants were allocated to the intervention arm. At baseline, participants had a mean BMI of 32.6 kg/m2. Most participants were Latino or Hispanic (n=200, 45.1%) or non-Latino or Hispanic White (n=115, 26%). In total, 53% (n=235) of participants had at least 1 visit with weight measured in the primary time window. The intervention group had a higher proportion with ≤3% weight gain at 6 months (risk ratio=1.12, 95% CI 0.94-1.28; risk difference=9.5, 95% CI -4.5 to 16.4 percentage points). This difference attenuated to the null by 24 months (risk ratio=1.00, 95% CI 0.82-1.20; risk difference=0.2, 95% CI -12.1 to 11.0 percentage points).

CONCLUSIONS

In adults with overweight or obesity receiving primary care at a community health center, we did not find long-term evidence to support the dissemination of a digital health intervention for weight gain prevention.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03003403; https://clinicaltrials.gov/study/NCT03003403.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

RR2-10.1186/s12889-019-6926-7.

Impact of meltwater flow intensity on the spatiotemporal heterogeneity of microbial mats in the McMurdo Dry Valleys, Antarctica

The meltwater streams of the McMurdo Dry Valleys are hot spots of biological diversity in the climate-sensitive polar desert landscape. Microbial mats, largely comprised of cyanobacteria, dominate the streams which flow for a brief window of time (~10 weeks) over the austral summer. These communities, critical to nutrient and carbon cycling, display previously uncharacterized patterns of rapid destabilization and recovery upon exposure to variable and physiologically detrimental conditions. Here, we characterize changes in biodiversity, transcriptional responses and activity of microbial mats in response to hydrological disturbance over spatiotemporal gradients. While diverse metabolic strategies persist between marginal mats and main channel mats, data collected from 4 time points during the austral summer revealed a homogenization of the mat communities during the mid-season peak meltwater flow, directly influencing the biogeochemical roles of this stream ecosystem. Gene expression pattern analyses identified strong functional sensitivities of nitrogen-fixing marginal mats to changes in hydrological activities. Stress response markers detailed the environmental challenges of each microhabitat and the molecular mechanisms underpinning survival in a polar desert ecosystem at the forefront of climate change. At mid and end points in the flow cycle, mobile genetic elements were upregulated across all mat types indicating high degrees of genome evolvability and transcriptional synchronies. Additionally, we identified novel antifreeze activity in the stream microbial mats indicating the presence of ice-binding proteins (IBPs). Cumulatively, these data provide a new view of active intra-stream diversity, biotic interactions and alterations in ecosystem function over a high-flow hydrological regime.

The Balance protocol: a pragmatic weight gain prevention randomized controlled trial for medically vulnerable patients within primary care

BACKGROUND

For patients with obesity who are not ready for or experience barriers to weight loss, clinical practice guidelines recommend provider counseling on preventing further weight gain as a first-line treatment approach. Unfortunately, evidence-based weight gain prevention interventions are not routinely available within primary care. To address this gap, we will implement a pragmatic 12-month randomized controlled trial of a digital weight gain prevention intervention delivered to patients receiving primary care within a network of Federally Qualified Community Health Centers in central North Carolina.

METHODS

Balance (Equilibrio in Spanish) is a pragmatic effectiveness trial that will randomize adult patients who have overweight or obesity (BMI of 25-40 kg/m²) to either: 1) a weight gain prevention intervention with tailored behavior change goals and tracking, daily weighing on a network-connected electronic scale, and responsive weight and goal coaching delivered remotely by health center registered dietitians; or 2) a usual care program with automated healthy living text messages and print materials and routine primary care. The primary outcome will be weight gain prevention at 24-months, defined as ≤3% change in baseline weight. To align with its pragmatic design, trial outcome data will be pulled from the electronic health record of the community health center network.

DISCUSSION

For underserved, often rurally-located patients with obesity, digital approaches to promote a healthy lifestyle can curb further weight gain. Yet enrolling medically vulnerable patients into a weight gain prevention trial, many of whom are from racial/ethnic minorities, can be difficult. Despite these potential challenges, we plan to recruit a large, diverse sample from rural areas, and will implement a remotely-delivered weight gain prevention intervention to medically vulnerable patients. Upcoming trial results will demonstrate the effectiveness of this pragmatic approach to implement and evaluate a digital weight gain prevention intervention within primary care.

TRIALS REGISTRATION

NCT03003403 . Registered December 28, 2016.

Effectiveness of an App and Provider Counseling for Obesity Treatment in Primary Care

INTRODUCTION

Obesity treatment is less successful for socioeconomically disadvantaged populations, particularly when delivered in primary care. Digital health strategies can extend the reach of clinical obesity treatments to care settings serving patients at highest risk.

METHODS

Track was an effectiveness RCT of a 12-month digital weight-loss intervention, embedded within a community health center system. Participants were 351 adult patients (aged 21-65 years) with obesity and hypertension, diabetes, and hyperlipidemia. Patients were randomized to usual care (n=175) or an intervention (n=176) comprising app-based self-monitoring of behavior change goals with tailored feedback, a smart scale, dietitian-delivered counseling calls, and clinician counseling informed by app-generated recommendations, delivered via electronic health record. The primary outcome was 12-month weight change. Randomization began on June 18, 2013, final assessments were completed on September 10, 2015. Data analysis was conducted in 2016 and 2017. The trial retained 92% of usual care and 96% of intervention participants at 12 months.

RESULTS

The Track intervention produced larger weight losses relative to usual care at 6 months (net effect: -4.4 kg, 95% CI= -5.5, -3.3, p<0.001) and 12 months (net effect: -3.8 kg, 95% CI= -5.0, -2.5, p<0.001). Intervention participants were more likely to lose ≥5% of their baseline weight at 6 months (43% vs 6%, p<0.001) and 12 months (40% vs 17%, p<0.001). Intervention participants completing ≥80% of expected self-monitoring episodes (-3.5 kg); counseling calls (-3.0 kg); or self-weighing days (-4.4 kg) lost significantly more weight than less engaged intervention participants (all p<0.01).

CONCLUSIONS

A digital obesity treatment, integrated with health system resources, can produce clinically meaningful weight-loss outcomes among socioeconomically disadvantaged primary care patients with elevated cardiovascular disease risk.

TRIAL REGISTRATION

This study is registered at www.clinicaltrials.gov NCT01827800.

Abstract P5-08-06: Impact of a decision-support tool on the utilization of colony-stimulating factors and incidence of febrile neutropenia among patients with breast cancer

Background:

Following the 2012 American Society of Clinical Oncology's Choosing Wisely campaign recommendation against the routine use of colony-stimulating factors (CSFs) for the primary prevention of febrile neutropenia (FN) in patients with ≤ 20% risk, an evidence-based clinical decision-support tool (CSF decision tool) was implemented to promote risk-appropriate CSF use in breast cancer patients receiving chemotherapy by a national payer in the United States (US). We hypothesized that there should be no change in pre- and post-implementation FN rates if the CSF decision tool had promoted appropriate FN risk stratification among breast cancer patients.

Methods:

A retrospective observational cohort study design was used to analyze data from a national payer administrative claims database of nearly 40 million lives geographically spread across the US. The CSF decision tool was first implemented in 2014, with a staggered implementation across states (July 1, 2014 - November 1, 2014). Study subjects were female patients, aged ≥ 18 years, who initiated chemotherapy for breast cancer in the time periods before or after the implementation of the decision tool (July 1, 2014 through March 30, 2015). Patients were assigned to case (defined as patients in the states where the CSF decision tool had been implemented) or control (defined as patients in states where the CSF decision tool had yet to be implemented) cohort. Patients in each cohort were followed up to 6 months after the first chemotherapy dose in the pre- and post-implementation periods. The outcomes were changes in the incidence of FN and CSF use rates, respectively. Rates of FN and CSF use were compared between the cohorts using difference-in-differences models; generalized estimating equations were used to adjust for differences in baseline risk factors including age, history of neutropenia or infections.

Results:

The final study population comprised 7,224 patients: 4,001 and 3,223 in the case and control cohorts, respectively. There was a higher proportion of patients who were 65 years or older in the case cohort compared to the control (22% vs 18%, p: &lt;0.001). Otherwise, the cohorts were comparable in FN risk factors at baseline in pre- and post-implementation periods.

In adjusted regression results, pre- and post-implementation FN rates were not significantly different for both case (5.38% to 5.65%) and control (5.07% to 5.13%) cohorts, [p=0.778]. Use of CSF in the pre- and post-implementation periods decreased from 75% to 69% in the case cohort compared with a reduction from 72% to 71% in the control cohort: an absolute difference of 5.4% decrease in CSF use associated with the implementation of the decision support tool [p= 0.006].

Conclusion:

Despite a modest reduction in CSF use, we found no evidence of an increase in FN rates after the implementation of the CSF decision tool. Given the lack of impact of the Choosing Wisely campaign on inappropriate CSF use; our findings suggest that beyond the educational efforts and media campaigns, a greater reduction in unnecessary CSF use can be achieved through the use of clinical decision algorithms to reduce practice variation and improve adherence to national guideline recommendations.

Citation Format: Adeboyeje G, Agiro A, Goodwin A, DeVries A, Malin J. Impact of a decision-support tool on the utilization of colony-stimulating factors and incidence of febrile neutropenia among patients with breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P5-08-06.

How successful are oncologists in identifying patient distress, perceived social support, and need for psychosocial counselling?

20-40% of cancer patients show emotional distress. Psychosocial support should be offered to severely distressed patients. However, little is known about the selection of patients to whom such support should be offered. This study investigated oncologists' ability to identify such patients. In a consecutive series of 298 cancer patients undergoing radiotherapy, distress, perceived social support and desire for supportive counselling were assessed using screening instruments. Simultaneously, 8 oncologists estimated patient distress and need for psychosocial support. A complete set of data was obtained in 80.2% of cases. Concordance of the oncologists' estimation of patient distress and perceived social support with the results of the screening instruments was weak (kappa = 0.10 and kappa = 0.05). Oncologists recognized the presence of severe distress only in 11 of the 30 severely distressed patients. Correct perception of distress was lower in patients with head and neck cancer and lung cancer and in lower class patients. Oncologists' recommendations for supportive counselling did not correlate with patient distress or the amount of perceived support but rather with progressive disease and less denial behaviour. Our results underline the need for educating oncologists in order to improve their ability to identify patient distress.

[Perfusion-index values evaluated by dynamic magnetic resonance imaging in advanced rectal carcinoma. A new predictor of response to preoperative radiochemotherapy?]

PURPOSE

The aim of our study was to evaluate in vivo the influence of tumor microcirculation data on therapy outcome.

PATIENTS AND METHODS

Tumor perfusion data of primary rectal carcinoma (n = 14, cT3) who underwent preoperative chemoradiation have been analyzed (Table 1). The perfusion data were acquired at the beginning and at the end of therapy by use of an ultrafast T1-mapping sequence on a whole-body magnetic resonance imager. The gadolinium-DTPA concentration-time-curves were evaluated for arterial blood and tumor before, during and after intravenous constant rate infusion and from that the perfusion index (PI) was calculated. Subsequent resection of the tumors allowed for a correlation of perfusion index values with the pathological classification.

RESULTS

Nine patients showed a T downstaging (ypT0-2, group 1), 5 patients did not (ypT3, group 2). The initial mean perfusion index value of group 1 (n = 9) was 8.2 ml/min/100 g (+/- 2) and for group 2 (n = 5) 10.4 ml/min/100 g (+/- 0.4). The difference in perfusion index values before chemoradiation between group 1 and group 2 was significant different (p = 0.012, Mann-Whitney test). The perfusion index value at the end of therapy of group 1 (n = 6) was 9.6 ml/min/100 g (+/- 2.8) and for group 2 (n = 4) 10.7 ml/min/100 g (+/- 1.6). The difference in perfusion index values after chemoradiation between group 1 and group 2 was not significant different (Table 2).

CONCLUSION

Our used perfusion index value combines 2 parameters: tumor perfusion and extraction fraction. Therefore a significant negative influence on therapy outcome of high perfusion index values could be explained possibly by areas with a high portion of high perfusion (e.g. av-shunts) and a low extraction fraction (= low exchange of nutrients). However, we could show a significant negative influence of high perfusion index values on therapy outcome (p = 0.012). Because the tumor stage has a significant influence on tumor-free survival, there is a possibility for using initial perfusion index values as a new prognostic factor in rectal carcinoma without sphincter infiltration undergoing a preoperative chemoradiation. To examine this hypotheses a prospective trial is in preparation.

Use of complementary and alternative medicine by cancer patients is not associated with perceived distress or poor compliance with standard treatment but with active coping behavior: a survey

BACKGROUND

Complementary and alternative medicine (CAM) is often used by cancer patients. Data on characteristics of users, concomitant psychologic disturbance, and compliance with standard treatment continue to be controversial. Use of and interest in CAM and their correlation with psychologic disturbance, ways of coping with illness, and compliance with standard treatment were examined in this study.

METHODS

The authors conducted a survey in a consecutive sample of 205 cancer patients undergoing radiotherapy, using a structured questionnaire to record use of and interest in CAM, the Hospital Anxiety and Depression Scale, the Hornheide Questionnaire to assess patient distress and social support, and the Freiburg Questionnaire of Coping with Illness.

RESULTS

Of the 172 participants, 24.4% (response rate, 83.9%) reported use of CAM, and 31.4% reported not having used but being interested in such methods. Logistic regression analysis including clinical, demographic, and psychologic characteristics as independent variables yielded 3 predictors of use of or interest in CAM: younger age (P = 0.004; odds ratio (OR), 0.96), progressive cancer (P = 0.064; OR, 1.47), and active coping behavior (P = 0.016; OR, 1.65). Patients interested in or using CAM did not show more psychologic disturbance, poorer social support, or less trust in medicine or compliance with radiotherapy than subjects without such interest.

CONCLUSIONS

Use of CAM by cancer patients is not associated with perceived distress or poor compliance with medical treatment but with active coping behavior. Patients seem to consider CAM as supplementary to standard medical methods and one way of avoiding passivity and of coping with feelings of hopelessness.

Proton radiation therapy for chordomas and chondrosarcomas of the skull base

OBJECT

Local tumor control, patient survival, and treatment failure outcomes were analyzed to assess treatment efficacy in 58 patients in whom fractionated proton radiation therapy (RT) was administered for skull base chordomas and chondrosarcomas.

METHODS

Between March 1992 and January 1998, a total of 58 patients who could be evaluated were treated for skull base tumors, 33 for chordoma and 25 for chondrosarcoma. Following various surgical procedures, residual tumor was detected in 91% of patients; 59% demonstrated brainstem involvement. Target dosages ranged from 64.8 and 79.2 (mean 70.7) Co Gy equivalent. The range of follow up was 7 to 75 months (mean 33 months). In 10 patients (17%) the treatment failed locally, resulting in local control rates of 92% (23 of 25 patients) for chondrosarcomas and 76% (25 of 33 patients) for chordomas. Tumor volume and brainstem involvement influenced control rates. All tumors with volumes of 25 ml or less remained locally controlled, compared with 56% of tumors larger than 25 ml (p = 0.02); 94% of patients without brainstem involvement did not experience recurrence; in patients with brainstem involvement (and dose reduction because of brainstem tolerance constraints) the authors achieved a tumor control rate of 53% (p = 0.04). Three patients died of their disease, and one died of intercurrent disease. Actuarial 5-year survival rates were 100% for patients with chondrosarcoma and 79% for patients with chordoma. Grade 3 and 4 late toxicities were observed in four patients (7%) and were symptomatic in three (5%).

CONCLUSIONS

High-dose proton RT offers excellent chances of lasting tumor control and survival, with acceptable risks. In this series all small- and medium-sized tumors with no demonstrable brainstem involvement have been controlled; all such patients are alive. Surgical debulking enhanced delivery of full tumoricidal doses, but even patients with large tumors and disease abutting crucial normal structures benefited.

[The role of radiotherapy in the treatment of malignant meningiomas]

PURPOSE

Most malignant meningiomas will recur following surgical resection only. The role of irradiation and radiation dose levels is poorly defined. This study reviews a single institution experience using both, conventional and high doses > or = 60 Gy/CGE radiation regimen.

PATIENTS AND METHODS

Between 1974 and 1995 16 patients with histologically proven malignant meningioma underwent radiation therapy (RT). Age at diagnosis ranged between 6 and 79 years (median: 49 years). Three patients reported previous irradiation to the head at least 14 years prior to diagnosis. Ten patients were treated for primary, and 6 patients for recurrent disease. Six patients underwent gross total and 10 patients subtotal resection (Table 1). RT was delivered using conventional, megavoltage photons or combined 160 MeV proton and photon irradiation. Except 1 patient, who died during RT, the radiation doses ranged between 40 and 70 Gy/CGE (= Cobalt Gray Equivalent) (median: 58 Gy/CGE, Table 2).

RESULTS

With median observation time of 59 months (range: 10 to 155 months), actuarial local control rates at 5 and 8 years were 52% and 17%, respectively. Target doses > or = Gy/CGE resulted in significantly improved tumor control (100%) compared to < 60 Gy/CGE (17%) (p = 0.0006, Table 3 and Figure 1). Improved local control translated also in increased overall survival: 87% (> or = 60 Gy/CGE) versus 15% (< 60 Gy/CGE) at 5 years (p = 0.025, Figure 2). At time of analysis, 6/16 patients (38%) were alive. Two patients developed symptomatic brain damage at doses of 59.3 and 72 Gy/CGE.

CONCLUSION

Conformal, radiation therapy with target doses > or = 60 Gy/CGE, in this study by use of combined proton and photon irradiation, can significantly improve chances of long-term local control and survival for patients diagnosed with these challenging tumors.

Comparison of chromosome telomere integrity in multiple tissues from subjects at different ages

Telomere DNA, at the ends of each chromosome, is conserved in nature and required for chromosome replication and stability. Reduction in telomere length has been observed in several malignancies as well as in leukocytes from healthy persons with advancing age. There is a paucity of data regarding telomere length and the effects of in vivo aging in different tissues. These data could be helpful in interpreting telomere length and understanding the role of telomere integrity and telomerase activity in malignant cells. We report telomeric DNA integrity studies of blood and skin collected from eight Caucasians of both sexes representing each decade of life from the fetus to 72 years of age without exposure to chemotherapy or radiation. In addition, telomeric data from 15 other tissues from the fetus and 8 other tissues from the 72-year-old male were examined. No significant differences were found in the shortest telomere size, the average telomere size, or telomere size variation between blood and skin from subjects at different ages. The average telomere size was 11.7 +/- 2.2 kb for blood and 12.8 +/- 3.7 for skin in all subjects studied. The shortest telomere length was 5.4 +/- 1.9 kb for blood and 4.3 +/- 0.9 kb for skin. Significant differences (P < 0.001) were found in the overall length of the DNA hybridization signal representing the shortest telomere size and the length of the DNA peak migration hybridization signal representing variation in telomere size between the 20-week fetus and the 72-year-old male. The 72-year-old male showed the shortest telomeres and the most variation (heterogeneity) in telomere size for all tissues studied, but the greatest differences were observed in blood compared with other tissues (e.g., average telomere length was 12.2 kb in the fetus and 7.2 kb in the 72-year-old male). The size of the telomere was negatively correlated with age for all tissues studied.

Pharmacokinetic MRI for assessment of malignant glioma response to stereotactic radiotherapy: initial results

The purpose of this study was to assess the value of dynamic, contrast-enhanced MRI in patients with malignant glioma (a) to predict before stereotactic radiotherapy local tumor control, (b) to investigate temporal changes in tumor microcirculation after stereotactic radiotherapy, and (c) to analyze whether malignant glioma response may be predicted earlier by alterations in the tissue pharmacokinetics rather than in terms of tumor volume. Ninety MRI studies were performed of 18 patients with malignant glioma before and 6, 18, 26, 52, and 72 weeks after the end of stereotactic radiotherapy. The signal time courses of the contrast-enhanced tumors were analyzed using a pharmacokinetic two-compartment model that calculates for the parameter A, reflecting the degree of MRI signal enhancement [no units] and the exchange rate constant k21 [min(-1)]. Before radiotherapy, the amplitude A was significantly (P < .05) lower in patients with subsequent local tumor control (n = 8; mean A = .34 +/- .15) compared to patients without subsequent local tumor control (n = 10; mean A = .94 +/- .71). In the local tumor control group, early after stereotactic radiotherapy (at 6-18 weeks), there was a significant (P < .05) time-dependent decrease in the parameter k21, whereas there was still no alteration in the tumor volume. A low amplitude A before radiotherapy, combined with an early drop of k21 after stereotactic radiotherapy, reliably characterized the group of patients with subsequent tumor volume decrease. Our preliminary results suggest that two contrast-enhanced dynamic MR studies, one before and one early after stereotactic radiotherapy, offer important information on local tumor control within the first 6 to 18 weeks after stereotactic radiotherapy. Moreover, this response may be evidenced before tumor volume changes and provides a therapeutic window to broaden treatment options and to improve treatment outcome.

Lectin intravital perfusion studies in tumor-bearing mice: micrometer-resolution, wide-area mapping of microvascular labeling, distinguishing efficiently and inefficiently perfused microregions in the tumor

Intravital lectin perfusion was combined with computer-guided scanning digital microscopy to map the perfused elements of the vasculature in tumor-bearing mice. High-precision composite images (spatial precision 1.3 micron and optical resolution 1.5 micron) were generated to permit exact positioning, reconstruction, analysis, and mapping of entire tumor cross-sections (c. 1 cm in diameter). Collation of these mosaics with nuclear magnetic resonance maps in the same tumor plane identified sites of rapid contrast medium uptake as tumor blood vessels. Digitized imaging after intravital double labeling allowed polychromatic visualization of two different types of mismatched staining. First, simultaneous application of two lectins, each bearing a different fluorochrome, revealed organ-specific differential processing in the microvascular wall. Second, sequential application of two boluses of one lectin, bearing different fluorochromes successively, distinguished between double-labeled microvessels, representing efficiently perfused vascular segments, and single-labeled microvessels, with inefficient or intermittent perfusion. Intravital lectin perfusion images of blood vessels in the vital functional state thus highlighted biologically significant differences in vessel function and served as high-resolution adjuncts to MR imaging.

Ketoconazole in the prevention of acute respiratory distress syndrome

We conducted a critical review of the literature on ketoconazole in preventing acute respiratory distress syndrome (ARDS), a serious disorder associated with high mortality. Two double-blind, prospective, placebo-controlled, randomized trials compared ketoconazole with placebo for prophylaxis of ARDS. In one trial, compared with placebo, ketoconazole resulted in a reduced frequency of ARDS (6% vs 31%, p<0.01), lower plasma thromboxane B2 levels (33 vs 75 pg/ml, p<0.05), and shorter intensive care unit stay (7 vs 15.5 days, p<0.05). In the second trial the drug reduced the frequency of ARDS (15% vs 64%, p=0.002), lowered thromboxane B2 levels (83 vs 143 pg/ml), and reduced mortality (15% vs 39%, p=0.05) compared with placebo. Larger multicenter studies are warranted to validate the findings of these two trials.

Do specialists order too many tests? The case of allergists and pediatric asthma

BACKGROUND

Is the practice style of specialists overly reliant on diagnostic tests? Health maintenance organization managers and other clinicians have been critical of the high cost practice styles of specialists, but if the specialists' practice style ultimately results in similar or lower total costs because of better outcomes in the treatment of exceptional cases, then such practice styles are cost-effective and should be encouraged. Indeed, if this is the case, not employing a test-intensive practice style could be considered negligent under a legal criterion.

OBJECTIVE

We attempted to determine whether the care of pediatric asthmatic patients by allergists is characterized by more testing, but by better, less costly outcomes than care by non-allergists.

METHODS

We used administrative data on pediatric asthmatic cases from a large health care plan from 1992 to determine whether patients treated by allergists received more tests, cost more, and had fewer asthmatic management breakdowns than patients treated by non-allergists. We used regression analysis to hold constant aspects of the patient's case mix.

RESULTS

Although allergists ordered significantly more tests than non-allergists, their overall treatment costs were similar. Patients treated by allergists had fewer management breakdowns.

CONCLUSIONS

These results suggest that the allergists' test-intensive practice style is cost-effective.

Evidence for genetic heterogeneity of malignant hyperthermia susceptibility

A locus for malignant hyperthermia susceptibility (MHS) has been localized on chromosome 19q12-13.2, while at the same time the gene encoding the skeletal muscle ryanodine receptor (RYR1) also has been mapped to this region and has been found to be tightly linked to MHS. RYR1 was consequently postulated as the candidate for the molecular defect causing MHS, and a point mutation in the gene has now been identified and is thought to be the cause of MH in at least some MHS patients. Here we report the results of a linkage study done with 19q12-13.2 markers, including the RYR1 cDNA, in two Bavarian families with MHS. In one of the families, three unambiguous recombination events between MHS and the RYR1 locus were found. In the second family only one informative meiosis was seen with RYR1. However, segregation analysis with markers for D19S75, D19S28, D19S47, CYP2A, BCL3, and APOC2 shows that the crossovers in the first family involve the entire haplotype defined by these markers flanking RYR1 and, furthermore, reveals multiple crossovers between these haplotypes and MHS in the second family. In these families, pairwise and multipoint lod scores below -2 exclude MHS from an interval spanning more than 26 cM and comprising the RYR1 and the previously described MHS locus. Our findings thus strongly suggest genetic heterogeneity of the MHS trait and prompt the search for another MHS locus.

Mucin biosynthesis. Enzymic properties of human-tracheal epithelial GDP-L-fucose:beta-D-galactoside alpha-(1----2)-L-fucosyltransferase

The human-tracheal, epithelial alpha-(1----2)-L-fucosyltransferase that transfers L-fucose from GDP-L-fucose to an acceptor containing a beta-D-galactopyranosyl group at the nonreducing terminal was characterized. Optimal enzyme activity was obtained at pH 6.5. 20-30mM MnCl2 (or CaCl2), and 0.05% Triton X-100 or 0.5% Tween 20. Mg2+ and Ba2+ ions moderately enhanced the enzyme activity, whereas Fe2+, Co2+, Zn2+, and Cd2+ ions were inhibitory. The enzyme activity was inhibited by N-ethylmaleimide and nucleotides of guanine, inosine, xanthine, and uridine. However, ATP and dithiothreitol did not affect the enzyme activity. The apparent Michaelis constant for GDP-L-fucose, freezing point-depressing glycoproteins (expressed as Gal----GalNAc----Thr), and phenyl beta-D-galactopyranoside was 0.29, 5.70, and 25.4mM, respectively. Under alkali-borohydride conditions (0.05M NaOH-M NaBH4, 45 degrees, 20 h), an L-[14C]fucosyltrisaccharide was released from the product obtained by use of freezing point-depressing glycoprotein as the acceptor. The alpha-L anomeric configuration of the fucoside was determined by the release of L-[14C]fucose from the purified trisaccharide by Turbo cornutus alpha-L-fucosidase. The (1----2) linkage of the L-fucosyl group to the D-galactosyl residue was established by methylation technique (m.s.-g.l.c.). The present enzyme has properties similar to those of the human milk alpha-(1----2)-L-fucosyltransferase which is encoded by a secretor gene.