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R Singleton

Publications and source records attributed to R Singleton.

At least 19 recordsLinked to original sources
PubMed2000

Bronchiectasis in Alaska Native children: causes and clinical courses.

Although bronchiectasis has become a rare condition in U.S. children, it is still commonly diagnosed in Alaska Native children in the Yukon Kuskokwim Delta. The prevalence of bronchiectasis has not decreased in persons born during the 1980s as compared with those born in the 1940s. We reviewed case histories of 46 children with bronchiectasis. We observed that recurrent pneumonia was the major preceding medical condition in 85% of patients. There was an association between the lobes affected by pneumonia and the lobes affected by bronchiectasis. Eight (17%) patients had surgical resection of involved lobes. We conclude that the continued high prevalence of bronchiectasis appears to be related to extremely high rates of infant and childhood pneumonia. Pediatr Pulmonol. 2000;29:182-187. Published 2000 Wiley-Liss, Inc.

Adolescent↗
PubMed2000

From bacteriology to biochemistry: Albert Jan Kluyver and Chester Werkman at Iowa State.

This essay explores connections between bacteriology and disciplinary evolution of biochemistry in this country during the 1930s. Many features of intermediary metabolism, a central component of biochemistry, originated as attempts to answer fundamental bacteriological questions. Thus, many bacteriologists altered their research programs to answer these questions. In doing so they changed their disciplinary focus from bacteriology to biochemistry. Chester Hamlin Werkman's (1893-1962) Iowa State career illustrates the research perspective that many bacteriologists adopted. As a junior faculty member in the Bacteriology Department in the late 1920s, Werkman faced a powerful professional dilemma: establishing a research identity that distinguished him from his colleagues with flourishing national and international reputations. His solution was to radically alter his research program from traditional bacteriology to a biochemistry program, which reflected the influence of the Dutch microbiologist/biochemist, Albert Jan Kluyver (1888-1956). Werkman was extremely successful in this career change. His laboratory made significant contributions to biochemistry, and Werkman achieved a notable degree of personal success. His career began in the shadow of his departmental bacteriological colleagues; within a decade he became the department's dominant research figure, as a biochemist. Werkman's personal success, however, had profound consequences for the disciplinary future of bacteriology at Iowa State.

Bacteriology↗
PubMed2000

Experience with the prevention of invasive Haemophilus influenzae type b disease by vaccination in Alaska: the impact of persistent oropharyngeal carriage.

OBJECTIVES: To report the epidemiology of invasive Haemophilus influenzae type b (Hib) disease in high-risk Alaska Native infants before and after universal infant Hib vaccination and evaluate an increase in invasive Hib disease in 1996 after changing Hib vaccine type. STUDY DESIGN: Statewide laboratory surveillance for invasive Hib disease has been conducted since 1980. Three cross-sectional Hib carriage studies were conducted in 1997 and 1998. RESULTS: The invasive Hib disease rate in Alaska Natives decreased from 332 cases per 100,000 children <5 years old in 1980-1991 to 17:100,000 in 1992-1995 but increased primarily in rural areas to 57.9:100,000 after a switch in Hib vaccine types. Carriage studies in 5 rural Alaska Native villages showed oropharyngeal Hib carriage as high as 9.3% in children aged 1 to 5 years; in contrast, carriage in urban Alaska Native children was <1%. CONCLUSIONS: Although Hib disease has decreased in Alaska, the rate of Hib disease and carriage in rural Alaska Natives did not decrease to the same extent as in non-Natives and urban Alaska Natives. Use of polyribosylribitol phosphate-outer-membrane protein conjugate vaccine for the first vaccine dose is critical to disease control in this population with continued transmission in infants <6 months of age. The ability to eliminate Hib carriage and disease may be affected by population characteristics, vaccination coverage, and Hib vaccine type used. This may pose a challenge to global elimination of Hib.

Adolescent↗
PubMed2000

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Journal Article↗
PubMed1999

Reemergence of invasive Haemophilus influenzae type b disease in a well-vaccinated population in remote Alaska.

Before vaccination, Alaska Natives experienced very high rates of invasive Haemophilus influenzae type b (Hib) disease and carriage. Vaccination with Hib conjugate vaccine PRP-OMP (polyribosylribitol phosphate Neisseria meningitidis outer membrane protein) began in 1991 and resulted in a sharp decline in cases. In 1996, after switching to a different Hib conjugate vaccine, DTP-HbOC (which combines diphtheria-tetanus-whole cell pertussis vaccines with HbOC [Hib oligosaccharide CRM197]), cases of invasive Hib disease increased, suggesting ongoing Hib transmission despite widespread vaccination. To determine the prevalence of and risk factors for carriage, a cross-sectional study of oropharyngeal Hib carriage was conducted among Alaska Native children aged 1-5 years in remote southwestern Alaska. Of 496 children with swabs taken, 46 (9.3%) were colonized with Hib. Carriage rates varied by village from 2.2% to 13.2% and by age from 6.1% in 1-year-olds to 14.7% in 5-year-olds. Crowding was associated with Hib carriage. Widespread vaccination with PRP-OMP Hib conjugate vaccine did not eliminate carriage in this population of Alaska Natives, and ongoing carriage contributed to disease resurgence.

Age Factors↗
PubMed1998

Overuse of parenteral antibiotics for wound care in an urban emergency department.

This study compared patterns of parenteral antibiotic treatment by emergency physicians with literature-derived guidelines in the management of wound care. All patients who received parenteral antibiotics as part of wound management in an urban general emergency department (ED) (annual volume 65,000) and did not receive subsequent consultation or admission were prospectively studied for 4 weeks (July 18 to August 15, 1994). Data collected included age, sex, antibiotic, route of administration, dose, cost, diagnosis, and board certification of emergency physician. Antibiotic choice and dose were reviewed by study-blinded physicians and compared with criteria based on a review of the current wound care literature. Wound characteristics justifying antibiotic prophylaxis were derived from the literature and included immunocompromised patient, wounds with debris or occurring under contaminated circumstances, wounds with cellulitis or purulent drainage, wounds older than 18 hours, and crush injuries. The study included 72 patients, and 13 (18%) antibiotic discrepancies were found. Cefazolin (n = 49 [64%]) and ceftriaxone (n = 25 [35%]) were the most commonly prescribed parenteral antibiotics, with cefazolin used in 9 (69%) and ceftriaxone in 4 (31%) of discrepant cases. There were not significant differences in discrepant parenteral antibiotic by emergency physicians' board certification. There were no significant demographic differences between patients receiving discrepant and nondiscrepant antibiotics. The excess cost of discrepant parenteral antibiotics during this small study period was $380. Approximately one fifth of the parenteral antibiotics prescribed during wound care administered in the ED were discrepant with current recommendations derived from the literature.

Adolescent↗
PubMed1998

RSV-associated hospitalizations in Alaska Native infants.

PURPOSE: Retrospective reviews for 1986-1992 suggested that Alaska Native children experience high rates of respiratory syncytial virus (RSV)-associated hospitalization; however, the epidemiology of RSV infections has been poorly characterized. METHODS: A prospective hospital-based surveillance study was undertaken to determine rates of RSV-associated hospitalization in Alaska Native children < 36 months from the Yukon-Kuskokwim Delta. RESULTS: During the first study year, October 1993 to September 1994, there were 40 RSV cases (hospitalization rate, 53/1,000 infants < 1 year of age); however, during the second year, October 1994 to September 1995, there were 251 RSV cases (hospitalization rate, 294/1,000 infants). An unusually high proportion, 12%, of RSV cases were < 1 month of age. Disease severity was higher for children with a history of prematurity, heart, or lung disease (p = .001, X2 analysis). Of 255 cell cultures during 1994-1995, 190 were RSV-positive, 11 were positive for influenza, 4 for adenovirus, and 1 for parainfluenza. This study demonstrates wide seasonal variation in a population with an extremely high RSV hospitalization rate; increased disease severity associated with young age and pre-existing medical conditions; and co-circulation of RSV with other viruses.

Alaska↗
PubMed1997

Correlation of thallium uptake with left ventricular wall thickness by cine magnetic resonance imaging in patients with acute and healed myocardial infarcts.

Myocardial infarction (MI) is characterized by cellular necrosis which undergoes fibrotic transformation over time. Cine magnetic resonance imaging (MRI) offers high-resolution 3-dimensional images of the left ventricular myocardium, allowing sampling of the myocardial wall thickness over the entire left ventricle. Tomographic (single-photon emission computed tomography [SPECT]) thallium images also provide 3-dimensional information on the location and level of thallium uptake, which has been shown to correlate with myocardial viability. The purposes of this study were: (1) to examine the relation between both end-diastolic and end-systolic wall thickness and normalized thallium-201 uptake over the left ventricle in a group of patients with MI, (2) to examine the relation between regional wall thickening and normalized thallium uptake, and (3) to examine the relation between thallium uptake and wall thickness both early and late after infarction. Twenty-four patients with MI underwent stress, redistribution, and reinjection thallium SPECT imaging and cine MRI within several days. Seventeen patients underwent imaging late after infarction and 7 underwent imaging early after infarction. Normalized thallium activity was correlated with MRI wall thicknesses at both end-diastole and end-systole for 18 segments for each ventricle. In addition, end-diastolic and end-systolic wall thicknesses were grouped by their corresponding thallium activity levels into percentiles. End-systolic wall thickness correlated significantly with normalized thallium uptake in 14 of 18 segments, end-diastolic wall thickness in only 4 of 18 segments, and wall thickening in only 3 of 18 segments. Mean values for end-diastolic and end-systolic wall thicknesses corresponding to severely reduced (<50%) normalized thallium activity were 9.9 +/- 1.1 and 8.5 +/- 0.6, respectively. Using receiver-operating curve analysis, end-systolic wall performed as a better diagnostic parameter than end-diastolic wall for identifying severely reduced thallium activity levels. For all levels of thallium activity, end-diastolic wall thicknesses were all thinner late versus early after MI, whereas end-systolic wall thickness was thinner only in the segments corresponding to severely reduced thallium activity. Based on these results, end-systolic wall thickness is the best noninvasive anatomic parameter of myocardial scar.

Adult↗