Controlled study of respiratory viruses and wheezing.
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Acute Disease↗
Biomedical subjects
S Schuh
Publications and source records attributed to S Schuh.
Bounds on the CP asymmetry in b --> sgamma decays.
We have measured the CP asymmetry A(CP) identical with[gamma(b-->sgamma)-gammab-->sgamma)]/[gamma(b-->sgamma)+gamma(b-->sgamma)] to be A(CP) = (-0.079+/-0.108+/-0.022) (1.0+/-0.030), implying that, at 90% confidence level, A(CP) lies between -0.27 and +0.10. These limits rule out some extreme non-standard-model predictions, but are consistent with most, as well as with the standard model.
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Study of tau decays to six pions and a neutrino.
The tau decays to six-pion final states have been studied with the CLEO detector at the Cornell Electron Storage Ring. The measured branching fractions are B(tau(-)-->2pi(-)pi(+)3pi(0)nu(tau)) = (2.2+/-0.3+/-0.4)x10(-4) and B(tau(-)-->3pi(-)2pi(+)pi(0)nu(tau)) = (1.7+/-0.2+/-0.2)x10(-4). A search for substructure in these decays shows that they are saturated by intermediate states with eta or omega mesons. We present the first observation of the decay tau(-)-->2pi(-)pi(+)omega(nu)tau and the branching fraction is measured to be (1.2+/-0.2+/-0.1)x10(-4). The measured branching fractions are in good agreement with the isospin expectations but somewhat below the conserved-vector-current predictions.
Journal Article↗
Observation of new states decaying into Lambda+(c)pi(-)pi(+).
Using 13.7 fb(-1) of data recorded by the CLEO detector at the Cornell Electron Storage Ring, we investigate the spectrum of charmed baryons which decay into Lambda+(c)pi(-)pi(+) and are more massive than the Lambda+(c)(2625) baryon. We find evidence for two new states: one is broad and has an invariant mass roughly 480 MeV above that of the Lambda+(c) baryon; the other is narrow with an invariant mass of 596+/-1+/-2 MeV above the Lambda+(c) mass.
Journal Article↗
Observation of the Omega(0)(c) Charmed Baryon at CLEO.
The CLEO experiment at the CESR collider has used 13.7 fb(-1) of data to search for the production of the Omega(0)(c) (css ground state) in e(+)e(-) collisions at square root of (s) approximately 10.6 GeV. The modes used to study the Omega(0)(c) are Omega(-)pi(+), Omega(-)pi(+)pi(0), Xi-K-pi(+)pi(+), Xi0K-pi(+), and Omega(-)pi(+)pi(+)pi(-). We observe a signal of 40.4+/-9.0(stat) events at a mass of 2694.6+/-2.6(stat)+/-1.9(syst) MeV/c(2), for all modes combined.
Journal Article↗
First observation of the decays B(0) --> D(*-)p_p pi+ and B(0) --> D(*-)p_n.
We report the first observation of exclusive decays of the type B-->D(*)N_NX, where N is a nucleon. Using a sample of 9.7x10(6)B_B pairs collected with the CLEO detector operating at the Cornell Electron Storage Ring, we measure the branching fractions B(B0-->D(*-)p_p pi(+)) = (6.5(+1.3)(-1.2)+/-1.0)x10(-4) and B(B0-->D(*-)p_n) = (14.5(+3.4)(-3.0)+/-2.7)x10(-4). Antineutrons are identified by their annihilation in the CsI electromagnetic calorimeter.
Journal Article↗
First observation of the sigma(*+)(c) baryon and a new measurement of the sigma(*+)(c) mass.
Using data recorded with the CLEO II and CLEO II.V detector configurations at the Cornell Electron Storage Rings, we report the first observation and mass measurement of the Sigma(*+)(c) charmed baryon, and an updated measurement of the mass of the Sigma(+)(c) baryon. We find M(Sigma(*+)(c))-M(Lambda(+)(c)) = (231.0+/-1.1+/-2.0) MeV, and M(Sigma(+)(c))-M(Lambda(+)(c)) = (166.4+/-0.2+/-0.3) MeV, where the errors are statistical and systematic, respectively.
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Study of B Decays to Charmonium States: B-->eta(c)K and B --> chi(c0)K.
In a sample of 9.66x10(6)B&Bmacr; pairs collected with the CLEO detector we make the first observation of B decays to an eta(c) and a kaon. We measure branching fractions B(B+-->eta(c)K+) = (0.69(+0.26)(-0.21)+/-0.08+/-0.20)x10(-3) and B(B degrees -->eta(c)K degrees ) = (1.09(+0.55)(-0.42)+/-0.12+/-0.31)x10(-3), where the first error is statistical, the second is systematic, and the third is from the eta(c) branching fraction uncertainty. From these we extract the eta(c) decay constant in the factorization approximation, f(eta(c)) = 335+/-75 MeV. We also search for B decays to a chi(c0) and a kaon. No evidence for a signal is found and we set 90% C.L. upper limits: B(B+-->chi(c0)K+)<4.8x10(-4) and B(B degrees -->chi(c0)K degrees )<5.0x10(-4).
Journal Article↗
Predictors of hospitalization in children with acute asthma.
OBJECTIVE: To identify predictors of long duration of bronchodilator therapy in children with acute asthma. STUDY DESIGN: An emergency department prospective cohort study of 278 children > or =12 months of age, with clinical and socioeconomic parameters collected at baseline and 4 hours after administration of corticosteroids. Patients were classified into short and long therapy groups, with interval from first albuterol dose to initiation of administration every 4 hours < or =12 or >12 hours, respectively. Predictors significant by univariate analysis were examined by multiple logistic regression. RESULTS: Five variables were associated with long therapy (n = 85) versus short therapy (n = 193): previous intensive care unit admission (odds ratio [OR] 7.2, 95% CI = 1.85, 27.7); baseline oxygen saturation < or =92% (OR 2.6, 95% CI = 0.89, 7.4), asthma score > or =6/9 (OR 2.9, 95% CI = 1.9, 4.37), oxygen saturation < or =92% (OR 6.6, 95% CI = 1.34, 32.0), and hourly albuterol dosing interval (OR 4.3, 95% CI = 0.82, 22.12) 4 hours after administration of corticosteroids. Probability of long therapy was 91.8% to 99% for > or =3 predictors, but only 40.6% to 61.8% for individual factors. CONCLUSION: A combination of 3 or more factors predicts long bronchodilator therapy and signals the need for hospitalization. Children with only one predictor can be safely treated in the emergency department or observation unit and reevaluated.
Acute Disease↗
Study of charmless hadronic B meson decays to pseudoscalar-vector final states.
We report results of searches for charmless hadronic B meson decays to pseudoscalar( pi(+/-), K+/-, pi(0), or K(0)(S))-vector( rho, K(*), or omega) final states. By using 9.7x10(6) BB pairs collected with the CLEO detector, we report the first observation of B(-)--->pi(-)rho(0), B(0)-->pi(+/-)rho(-/+), and B(-)-->pi(-)omega, which are expected to be dominated by hadronic b-->u transitions. The measured branching fractions are (10.4(+3.3)(-3.4)+/-2.1)x10(-6), (27.6(+8.4)(-7.4)+/-4.2)x10(-6), and (11.3(+3.3)(-2.9)+/-1. 4)x10(-6), respectively. Branching fraction upper limits are set for all of the other decay modes investigated.
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A comparison of inhaled fluticasone and oral prednisone for children with severe acute asthma.
BACKGROUND: Inhaled corticosteroids are effective in the treatment of children with asthma. It is uncertain how inhaled corticosteroids compare with oral corticosteroids in the management of severe acute disease. METHODS: We performed a double-blind, randomized trial involving 100 children five years of age or older who had severe acute asthma (indicated by a forced expiratory volume in one second [FEV1] that was less than 60 percent of the predicted value) and in whom the results could be evaluated. All were treated with an aggressive bronchodilator regimen and received one dose of either 2 mg of inhaled fluticasone through a metered-dose inhaler with a spacer or 2 mg of oral prednisone per kilogram of body weight. They were assessed hourly for up to four hours. RESULTS: The mean (+/-SD) base-line FEV1 as a percentage of the predicted value was 46.3+/-12.5 in the fluticasone group (51 subjects) and 43.9+/-9.9 in the prednisone group (49 subjects). The FEV1 increased by a mean of 9.4+/-12.5 percentage points in the fluticasone group and by 18.9+/-9.8 percentage points in the prednisone group four hours after therapy (P< 0.001). None of the children in the prednisone group had a reduction in FEV1 as a percentage of the predicted value from base line to four hours, as compared with 25 percent of those in the fluticasone group (P<0.001). Sixteen (31 percent) of the children treated with fluticasone were hospitalized, as compared with five (10 percent) of those treated with prednisone (P=0.01). CONCLUSIONS: Children with severe acute asthma should be treated with oral prednisone and not with inhaled fluticasone or a similar inhaled corticosteroid.
Administration, Inhalation↗
Observation of B --> K(+/-) pi(0) and B --> (K)0 pi(0), and evidence for B --> pi(+)pi(-).
We have studied charmless hadronic decays of B mesons into two-body final states with kaons and pions and observe three new processes with the following branching fractions: beta(B-->pi(+)pi(-)) = (4.3(+1. 6)(-1.4)+/-0.5)x10(-6), beta(B-->K(0)pi(0)) = (14.6(+5.9+2.4)(-5.1-3. 3))x10(-6), and beta(B-->K(+)/-pi(0)) = (11.6(+3.0+1.4)(-2.7-1.3))x10(-6). We also update our previous measurements for the decays B-->K(+)/-pi(-/+) and B+/--->K(0)pi(+/-).
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Two-body B meson decays to eta and eta('): observation of B --> eta K*.
In a sample of 19 x 10(6) produced B mesons, we have observed the decays B-->eta K(*) and improved our previous measurements of B-->eta'K. The branching fractions we measure for these decay modes are B(B+-->eta K(*+)) = (26.4(+9.6)(-8.2)+/-3.3)x10(-6), B(B(0)-->eta K(*0)) = (13.8(+5.5)(-4.6)+/-1.6)x10(-6), B(B(+)-->eta'K(+) = (80(+10)(-9)+/-7)x10(-6), and B(B(0)-->eta'K0) = (89(+18)(-16)+/-9)x10(-6). We have searched with comparable sensitivity for related decays and report upper limits for these branching fractions.
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Measurement of charge asymmetries in charmless hadronic B meson decays.
We search for CP-violating charge asymmetries (alpha(CP)) in the B meson decays to K(+/-)pi(-/+), K(+/-)pi(0), K(0)(S)pi(+/-), K(+/-)eta('), and omega pi(+/-). Using 9.66 million upsilon(4S) decays collected with the CLEO detector, the statistical precision on alpha(CP) is in the range of +/-0.12 to +/-0.25 depending on decay mode. While CP-violating asymmetries of up to +/-0.5 are possible within the standard model, the measured asymmetries are consistent with zero in all five decay modes studied.
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Comparison of albuterol delivered by a metered dose inhaler with spacer versus a nebulizer in children with mild acute asthma.
OBJECTIVE: In children with mild acute asthma, to compare treatment with a single dose of albuterol delivered by a metered dose inhaler (MDI) with a spacer in either a weight-adjusted high dose or a standard low-dose regimen with delivery by a nebulizer. STUDY DESIGN: In this randomized double-blind trial set in an emergency department, 90 children between 5 and 17 years of age with a baseline forced expiratory volume in 1 second (FEV1 ) between 50% and 79% of predicted value were treated with a single dose of albuterol, either 6 to 10 puffs (n = 30) or 2 puffs (n = 30) with an MDI with spacer or 0.15 mg/kg with a nebulizer (n = 30). RESULTS: No significant differences were seen between treatment groups in the degree of improvement in percent predicted FEV1 (P =.12), clinical score, respiratory rate, or O2 saturation. However, the nebulizer group had a significantly greater change in heart rate (P =.0001). Our study had 93% power to detect a mean difference in percent predicted FEV1 of 8 between the treatment groups. CONCLUSION: In children with mild acute asthma, treatment with 2 puffs of albuterol by an MDI with spacer is just as clinically beneficial as treatment with higher doses delivered by an MDI or by a nebulizer.
Adolescent↗
A comparison of nebulized budesonide, intramuscular dexamethasone, and placebo for moderately severe croup.
BACKGROUND: In children with croup, treatment with nebulized budesonide decreases symptoms, but it is uncertain how budesonide compares with dexamethasone, the conventional therapy for croup, and whether either reduces the rate of hospitalization. METHODS: We performed a double-blind, randomized trial involving 144 children with moderately severe croup. The children were treated with racepinephrine and a single dose of 4 mg of nebulized budesonide (48 children), 0.6 mg of intramuscular dexamethasone per kilogram of body weight (47 children), or placebo (49 children). The children were assessed before treatment and then hourly for five hours after treatment. Physicians who were unaware of the treatment assignments determined the children's need for further treatment and hospitalization. RESULTS: The characteristics of the groups were similar at base line, including the types of viruses identified, the types of croup, and the clinical severity of the illness. The overall rates of hospitalization were 71 percent in the placebo group (35 of 49 children), 38 percent in the budesonide group (18 of 48 children), and 23 percent in the dexamethasone group (11 of 47 children) (unadjusted P=0.001 for the comparison of budesonide with placebo, P<0.001 for the comparison of dexamethasone with placebo, and P=0.18 for the comparison of budesonide with dexamethasone). Children treated with budesonide or dexamethasone had a greater improvement in croup scores than those given placebo (P=0.03 and P<0.001, respectively), and those treated with dexamethasone had a greater improvement than those treated with budesonide (P=0.003). CONCLUSIONS: In children with moderately severe croup, treatment with intramuscular dexamethasone or nebulized budesonide resulted in more rapid clinical improvement than did the administration of placebo, with dexamethasone offering the greatest improvement. Treatment with either glucocorticoid resulted in fewer hospitalizations.
Administration, Inhalation↗
Ultrasonographic and clinical predictors of intussusception.
OBJECTIVE: The objective of this study was to determine the positive and negative clinical predictors of intussusception and the correlation of ultrasonography and air enema in establishing this diagnosis. STUDY DESIGN: This was a prospective descriptive cohort study. SETTING: This study was performed in a tertiary care pediatric emergency department. PARTICIPANTS: Eighty-eight of 245 candidates were assessed for clinical predictors of intussusception. All 245 cases were examined for correlation between ultrasonography and air enema. INTERVENTIONS: A questionnaire, ultrasonography, and air enema were used. RESULTS: Thirty-five of the 88 patients assessed for clinical predictors were positive for intussusception. Significant positive predictors were right upper quadrant abdominal mass (positive predictive value [PPV] 94%), gross blood in stool (PPV 80%), blood on rectal examination (PPV 78%), the triad of intermittent abdominal pain, vomiting, and right upper quadrant abdominal mass (PPV 93%, p = 0.0001), and the triad with occult or gross blood per rectum (PPV 100%, p = not significant). Significant negative predictors were a combination of > or = 3 of 10 clinically significant negative features (negative predictive value 77%, p = 0.035). Of the total 245 cases, intussusception (as confirmed by doughnut, target, or pseudokidney sign) was ruled out by ultrasonography in 97.4%. Alternate ultrasound findings comprised 27% of negative cases. CONCLUSIONS: Excellent positive predictors of intussusception were identified prospectively. Although no reliable negative predictors were found, patients at low risk may be screened by ultrasonography.
Air↗
Changes in treatment and outcomes of children receiving care in the intensive care unit for severe acute asthma.
OBJECTIVE: Significant changes have occurred in the intensity of treatment of children with severe asthma in the last decade. The objectives of this study are 1) to describe the changes in treatment of asthmatic children needing care in the intensive care unit (ICU) initially treated in our emergency department (ED) in 1983 to 1985 (I) and in 1990 to 1992 (II), and 2) to examine if these changes correspond to changes in clinical outcomes. DESIGN: Retrospective descriptive study. PATIENTS: All asthmatic children less than 18 years old treated in the ED and admitted to the ICU directly or via the ward with a primary diagnosis of asthma. SETTING: Pediatric tertiary care hospital. RESULTS: A total of 89 ICU admissions were required for patients initially treated in our ED, 54 in 1983 to 1985 and 35 in 1990 to 1992. In 1985, 29.7% of asthma patients required hospital admission and 0.5% needed ICU admission, while 30.7 and 0.7% required hospital and ICU admission, respectively, in 1992. Admissions to the ICU directly via the ED were similar in both time periods (I, 27; II, 30), while those admitted to the ICU via the ward decreased significantly (I, 27; II, 5; P < 0.01). Recently, while in the ED, these ICU patients, on average, were treated with < or =q1h albuterol inhalations longer (I, 1.7 hours; II, 3.4 hours; P < 0.001), more frequently (I, 1.8 inhalations/h; II, 3.3 inhalations/h; P < 0.001), and with greater dosages (I, 0.20 mg/kg/h; II, 0.55 mg/kg/h; P < 0.001), than previously. Only 72% of patients in 1983 to 1985 received i.v. steroids in the ED versus 100% in 1990 to 1992. Ward patients in 1990 to 1992 received < or =q1h inhalations for a greater proportion of their ward stay (I, 6.9/14.7 hours = 47%; II, 9.2/9.2 hours = 100%). There was a recent trend toward longer ICU treatment with < or =q1h albuterol inhalations (I, 8.7 hours; II, 12.3 hours; P = 0.24) and with i.v. albuterol (I, 29.4 hours; II, 37.4 hours; P = 0.26). Ventilation rates were low (I, 5/54 = 9.3%; II, 2/35 = 5.7%; P = NS) and the average duration of ICU stay remained unchanged (I, 40.6 hours; II, 42.1 hours; P = NS). CONCLUSIONS: Despite recent dramatic ED and ward treatment changes, ICU admission rates for pediatric asthma remain relatively constant. However, intensive treatment may have contributed to the decrease in ICU admissions via the ED to ward route in slightly less critical cases.
Acute Disease↗