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Biomedical subjects

David A Waltz

Publications and source records attributed to David A Waltz.

11 recordsLinked to original sources
PubMed2006

Membranous obliterative bronchitis: a proposed unifying model.

Three adults with cystic fibrosis (one after lung transplantation) presented with fever, chest pain, and acute radiographic changes. The changes included a cavitary lesion of the lung, acute dense infiltrates, and lobar collapse. After failing conventional antibiotic therapy, the patients underwent flexible bronchoscopy. All had bronchial obstruction by a membrane that had completely occluded the bronchial orifice at the bifurcation of the bronchi. Therapeutic interventions ranged from continuing intravenous antibiotics, bronchoscopy-assisted perforation of the membrane by sharp instrumentation, and transthoracic needle-guided perforation of the membrane with subsequent stenting of the orifice. The patients recovered, but the posttransplant patient had recurrent membranous obstructions with multiple interventions. The cause and triggers of the process are unknown. Based on repeated observations of the evolution of the membranes, and histologic material from bronchoscopies, we propose a putative paradigm of the natural history of the process. We suggest that local stimuli generate a richly vascularized granulation polyp, which progresses in a "shutter-like" motion to form partial or completely obstructive membranes. The subsequent course depends on the vascular supply to the membrane. We also propose that similar processes may be the underlying pathologic events in some cases of lung abscess and necrotizing pneumonia.

Adult↗
PubMed2005

Impact of Burkholderia dolosa on lung function and survival in cystic fibrosis.

RATIONALE: Chronic infection with Burkholderia cepacia complex bacteria in cystic fibrosis is associated with accelerated decline in pulmonary function and increased mortality. Clinical implications of the recently characterized genomovar VI, B. dolosa, are unknown. OBJECTIVES: Characterization of impact of B. dolosa on pulmonary function and mortality in cystic fibrosis. METHODS: We compared patients chronically infected with B. dolosa (n = 31) with unmatched patients with B. multivorans (n = 24) and with age- and sex-matched control subjects without Burkholderia species (n = 58). We analyzed rates of pulmonary function decline (% predicted FEV(1)) using a random effects model assuming segmented linear trends. All available FEV(1) measurements from 5 yr (median, 4.8) before until 2.5 yr (median, 1.5) after the first positive culture for Burkholderia (reference date) were analyzed. Survival was compared using the Kaplan-Meier method and proportional hazards model. MEASUREMENTS AND MAIN RESULTS: Baseline FEV(1) and rate of decline were similar in the cohorts. Decline in FEV(1) after the reference date accelerated in patients with B. dolosa (-2.3 percentage points/yr pre vs. -7.1 post, p = 0.002), but was unchanged in the B. multivorans and control patients (-2.3 vs. -0.8 post, p = 0.38, and -2.1 pre vs. -0.5 post, p = 0.20, respectively). The probability of dying within 18 mo of the reference date was 13, 7, and 3% for B. dolosa, B. multivorans, and control patients, respectively (B. dolosa vs. control hazard ratio, 10.8; 95% confidence interval, 1.3-92.8; p = 0.03). CONCLUSIONS: B. dolosa chronic infection in cystic fibrosis is associated with accelerated loss of lung function and decreased survival.

Adult↗
PubMed2005

Cutaneovisceral angiomatosis with thrombocytopenia.

We describe 10 children with multiple vascular lesions of the skin and gastrointestinal tract associated with sustained, minor thrombocytopenia. In some children, there was involvement of the lung (n = 5), bone (n = 2), liver (n = 1), spleen (n = 1), and muscle (n = 1). The cutaneous lesions were congenital, multifocal, discrete, red-brown and variably blue macules and papules; in 3 children, a large dominant plaque was also present. All children developed hematemesis and/or melena and endoscopic evaluation revealed several to numerous small mucosal lesions that involved all levels of the gastrointestinal tract. Three of 5 children with pulmonary nodules had cough and 1 also had hemoptysis. Biopsies of cutaneous, gastrointestinal, and pulmonary lesions showed thin-walled, blood-filled vascular channels and variable endothelial hyperplasia. The endothelial nuclei were elongated, round, crescentic, or hobnailed. Cytoplasmic and extracellular periodic acid-Schiff positive deposits were often present in the zones of endothelial hyperplasia. The platelets were small in some children, suggesting a primary defect, possibly accounting for the thrombocytopenia. Gastrointestinal hemorrhage and hemoptysis required antiangiogenic therapy. The constellation of findings defines a congenital proliferative disorder of blood vessels with a distinctive microscopic appearance. We have termed this relatively indolent or slowly progressive disorder cutaneovisceral angiomatosis with thrombocytopenia because this designation incorporates its major clinical and histopathologic features.

Angiogenesis Inhibitors↗
PubMed2005

Tracheomalacia and tracheobronchomalacia in children and adults: an in-depth review.

Tracheomalacia and tracheobronchomalacia are disorders that are encountered in both pediatric and adult medicine. Despite increasing recognition of these disease processes, there remains some uncertainty regarding their identification, causes, and treatment. This article is intended to be a comprehensive review of both the adult and pediatric forms of the diseases, and includes sections on the historical aspects of the disorders, and their classification, associated conditions, histopathology, and natural history. We also review the various modalities that are used for diagnosis as well as the state of the art of treatment, including airway stent placement and surgical intervention.

Adult↗
PubMed2004

Population-based newborn screening for genetic disorders when multiple mutation DNA testing is incorporated: a cystic fibrosis newborn screening model demonstrating increased sensitivity but more carrier detections.

OBJECTIVES: Newborn screening for cystic fibrosis (CF) provides a model to investigate the implications of applying multiple-mutation DNA testing in screening for any disorder in a pediatric population-based setting, where detection of affected infants is desired and identification of unaffected carriers is not. Widely applied 2-tiered CF newborn screening strategies first test for elevated immunoreactive trypsinogen (IRT) with subsequent analysis for a single CFTR mutation (DeltaF508), systematically missing CF-affected infants with any of the >1000 less common or population-specific mutations. Comparison of CF newborn screening algorithms that incorporate single- and multiple-mutation testing may offer insights into strategies that maximize the public health value of screening for CF and other genetic disorders. The objective of this study was to evaluate technical feasibility and practical implications of 2-tiered CF newborn screening that uses testing for multiple mutations (multiple-CFTR-mutation testing). METHODS: We implemented statewide CF newborn screening using a 2-tiered algorithm: all specimens were assayed for IRT; those with elevated IRT then had multiple-CFTR-mutation testing. Infants who screened positive by detection of 1 or 2 mutations or extremely elevated IRT (>99.8%; failsafe protocol) were then referred for definitive diagnosis by sweat testing. We compared the number of sweat-test referrals using single- with multiple-CFTR-mutation testing. Initial physician assessments and diagnostic outcomes of these screened-positive infants and any affected infants missed by the screen were analyzed. We evaluated compliance with our screening and follow-up protocols. All Massachusetts delivery units, the Newborn Screening Program, pediatric health care providers who evaluate and refer screened-positive infants, and the 5 Massachusetts CF Centers and their affiliated genetic services participated. A 4-year cohort of 323 506 infants who were born in Massachusetts between February 1, 1999, and February 1, 2003, and screened for CF at approximately 2 days of age was studied. RESULTS: A total of 110 of 112 CF-affected infants screened (negative predictive value: 99.99%) were detected with IRT/multiple-CFTR-mutation screening; 2 false-negative screens did not show elevated IRT. A total of 107 (97%) of the 110 had 1 or 2 mutations detected by the multiple- CFTR-mutation screen, and 3 had positive screens on the basis of the failsafe protocol. In contrast, had we used single-mutation testing, only 96 (87%) of the 110 would have had 1 or 2 mutations detectable by single-mutation screen, 8 would have had positive screens on the basis of the failsafe protocol, and an additional 6 infants would have had false-negative screens. Among 110 CF-affected screened-positive infants, a likely "genetic diagnosis" was made by the multiple-CFTR-mutation screen in 82 (75%) versus 55 (50%) with DeltaF508 alone. Increased sensitivity from multiple-CFTR-mutation testing yielded 274 (26%) more referrals for sweat testing and carrier identifications than testing with DeltaF508 alone. CONCLUSIONS: Use of multiple-CFTR-mutation testing improved sensitivity and postscreening prediction of CF at the cost of increased referrals and carrier identification.

Algorithms↗
PubMed2003

Efficiency of pulmonary administration of tobramycin solution for inhalation in cystic fibrosis using an improved drug delivery system.

STUDY OBJECTIVES: To determine whether tobramycin solution for inhalation (TSI) can be administered safely and more efficiently with a new-generation aerosol device, the AeroDose 5.5 RP inhaler (Aerogen; Mountain View, CA) than with the approved PARI LC PLUS nebulizer (PARI Respiratory Equipment; Monterey, CA) with Pulmo-Aide compressor (DeVilbiss Corp; Somerset, PA). Second, we wanted to ascertain which AeroDose-delivered tobramycin dose is equivalent to the standard 300-mg dose administered with the PARI LC PLUS. DESIGN: Open-label, randomized, multicenter, single-dose, three-period, four-treatment, active- control, crossover trial. SETTING: Nine US cystic fibrosis (CF) centers. PATIENTS: Fifty-three patients >or= 12 years of age with a confirmed diagnosis of CF, the ability to expectorate sputum, and FEV(1) of >or= 40% of predicted. METHODS: Subjects inhaled three single doses of TSI at 1-week intervals, as follows: conventional control treatment, 300 mg via the PARI LC PLUS; and two of three experimental treatments, 30, 60, or 90 mg via the AeroDose. FEV(1) was measured before and after dosing. After each dose, sputum and serum samples were collected at various intervals for 8 h, and urine was collected for 24 h to estimate lung and systemic tobramycin delivery. RESULTS: There were no significant differences between treatments in the change in FEV(1) 30 min after dosing or in the frequency of adverse events. Sputum and serum levels of tobramycin produced by the AeroDose 90-mg dose treatment approximated those achieved with the PARI LC PLUS 300-mg dose treatment. Nebulization times using the AeroDose inhaler were < 50% those of the PARI LC PLUS. CONCLUSIONS: Compared with the standard nebulizer, the AeroDose safely achieved an approximately threefold greater efficiency in the delivery of TSI to the lungs in less than half the time.

Administration, Inhalation↗