Public health nutrition practice in the United States.
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Demography↗
Biomedical subjects
D B Johnson
Publications and source records attributed to D B Johnson.
Cryosurgery and needle ablation of renal lesions.
Laparoscopic renal cryoablation is a minimally invasive alternative for treating renal tumors utilizing narrow probes cooled with a compressed gas such as argon or carbon dioxide. At this time, cryotherapy has shown the most promise as an alternative to partial nephrectomy as a nephron-sparing treatment for renal tumors. Radiofrequency ablation employs needle electrodes placed percutaneously directly into renal lesions to deliver energy, creating high temperatures leading to cell death. High-intensity focused ultrasound is a noninvasive technique in which focused ultrasound energy is applied to cause cell death within the focal zone. Microwave thermotherapy uses small applicators to deliver microwave energy to tissues, resulting in the generation of heat. Although RF, HIFU, and microwave thermotherapy show promise as energy sources for tumor ablation, they are in the early stages of development. Little is known about their acute and chronic histologic effects and long-term efficacy as a treatment for malignant disease. Further work is needed to develop cryosurgery and needle ablation in order to delineate what role these techniques will ultimately play in the management of RCC.
Catheter Ablation↗
A microbiological survey of Montserrat Island hydrothermal biotopes.
In March 1996, a survey of hydrothermal sites on the island of Montserrat was carried out. Six sites (Galway's Soufrière. Gages Upper and Lower Soufrières, Hot Water Pond, Hot River, and Tar River Soufrière) were mapped and sampled for chemical, ATP, and microbial analyses. The hydrothermal Soufrière sites on the slopes of the active Chances Peak volcano exhibited temperatures up to almost 100 degrees C and were generally either mildly acidic at pH 5-7 or strongly acidic at pH 1.5-3, but with some hot streams and pools of low redox potential at pH 7-8. Hot Water Pond sites, comprising a series of heated pools near the western shoreline of the island. were neutral and saline, consistent with subsurface heating of entrained seawater. Biological activity shown by ATP analyses was greatest in near-neutral pH samples and generally decreased as acidity increased. A variety of heterotrophic and chemolithotrophic thermophilic organisms were isolated or observed in enrichment cultures. Most of the bacteria that were obtained in pure culture were familiar acidophiles and neutrophiles, but novel, iron-oxidizing species of Sulfobacillus were revealed. These species included the first mesophilic iron-oxidizing Sulfobacillus strains to be isolated and a strain with a higher maximum growth temperature (65 degrees C) than the previously described moderately thermophilic Sulfobacillus species.
Adenosine Triphosphate↗
Laparoscopic cryoablation for renal-cell cancer.
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Animals↗
A medical digital library to support scenario and user-tailored information retrieval.
Current large-scale information sources are designed to support general queries and lack the ability to support scenario-specific information navigation, gathering, and presentation. As a result, users are often unable to obtain desired specific information within a well-defined subject area. Today's information systems do not provide efficient content navigation, incremental appropriate matching, or content correlation. We are developing the following innovative technologies to remedy these problems: 1) scenario-based proxies, enabling the gathering and filtering of information customized for users within a pre-defined domain; 2) context-sensitive navigation and matching, providing approximate matching and similarity links when an exact match to a user's request is unavailable; 3) content correlation of documents, creating semantic links between documents and information sources; and 4) user models for customizing retrieved information and result presentation. A digital medical library is currently being constructed using these technologies to provide customized information for the user. The technologies are general in nature and can provide custom and scenario-specific information in many other domains (e.g., crisis management).
Database Management Systems↗
Interactive software for generation and visualization of structured findings in radiology reports.
OBJECTIVE: Our objectives were to develop a user-friendly graphic interface for a module that integrates traditional radiology reporting, natural language processing, and editing capabilities; to facilitate the structuring of radiology reports as part of routine clinical practice; to use a commercial speech recognition module for online transcription; and to implement the module in a hardware-independent environment. CONCLUSION: After implementation, the module was tested with 150 chest radiology reports by two radiologists and assessed for ease of use and accuracy. Overall, accuracy was close to 90% and user satisfaction was high. When radiology reports are structured as a part of routine clinical practice, it is possible to accomplish intelligent indexing and retrieval to facilitate teaching and research.
Medical Records Systems, Computerized↗
The urinary tract response to entry of pathogens.
The urinary tract response to the entry of pathogens is complex and involves multiple aspects of the immune system. Herein we have divided them into cytokine, immunoglobulin, and cellular responses. Our current understanding suggests that interleukin 6 (IL-6) and IL-8 are the major contributors to the cytokine response. Both IL-6 and IL-8 are produced locally and systemically as part of the initiation of an inflammatory reaction. The cellular response becomes clinically apparent by the appearance of polymorphonuclear neutrophils (PMNs) in the urine. The contribution of gamma delta T-lymphocytes is beginning to be appreciated due to the use of gene-knockout mice in studies of urinary tract infection (UTI). B-lymphocytes are important because antibody response to UTI is important. In addition to the classic systemic antibody response, a local antibody response dominated by secretory immunoglobulin A (sIgA) has been shown to play a major role in the host response to UTI. Efforts to create a vaccine against UTI have focused on stimulation and intensification of this local sIgA production. Investigation continues to define the role of these responses, explain how they interact, and elucidate other aspects of the immune response to UTI that are yet unknown. Ultimately, this work aims to provide more effective treatment and prevention of UTI in those susceptible to invasions of the urinary tract by pathogens. Comprehension of how these responses interact may lead to a better understanding of UTI susceptibility and promote new and innovative types of treatment.
Animals↗
Müllerian-type epithelial tumor arising within a torsed appendix testis.
Because it is a remnant of the müllerian duct system, the appendix testis contains müllerian epithelium that theoretically may produce epithelial tumors similar to those that occur in the female genital tract. Few reports of tumors of müllerian origin arising in the testis exist, and rarely are neoplasms arising from the appendix testis identified. We present a case of a serous cystic neoplasm of low malignant potential derived from müllerian-type epithelium that was located in the torsed appendix testis of a young, otherwise healthy, boy.
Adolescent↗
Leaching of pyrite by acidophilic heterotrophic iron-oxidizing bacteria in pure and mixed cultures.
Seven strains of heterotrophic iron-oxidizing acidophilic bacteria were examined to determine their abilities to promote oxidative dissolution of pyrite (FeS2) when they were grown in pure cultures and in mixed cultures with sulfur-oxidizing Thiobacillus spp. Only one of the isolates (strain T-24) oxidized pyrite when it was grown in pyrite-basal salts medium. However, when pyrite-containing cultures were supplemented with 0.02% (wt/vol) yeast extract, most of the isolates oxidized pyrite, and one (strain T-24) promoted rates of mineral dissolution similar to the rates observed with the iron-oxidizing autotroph Thiobacillus ferrooxidans. Pyrite oxidation by another isolate (strain T-21) occurred in cultures containing between 0.005 and 0.05% (wt/vol) yeast extract but was completely inhibited in cultures containing 0.5% yeast extract. Ferrous iron was also needed for mineral dissolution by the iron-oxidizing heterotrophs, indicating that these organisms oxidize pyrite via the "indirect" mechanism. Mixed cultures of three isolates (strains T-21, T-23, and T-24) and the sulfur-oxidizing autotroph Thiobacillus thiooxidans promoted pyrite dissolution; since neither strains T-21 and T-23 nor T. thiooxidans could oxidize this mineral in yeast extract-free media, this was a novel example of bacterial synergism. Mixed cultures of strains T-21 and T-23 and the sulfur-oxidizing mixotroph Thiobacillus acidophilus also oxidized pyrite but to a lesser extent than did mixed cultures containing T. thiooxidans. Pyrite leaching by strain T-23 grown in an organic compound-rich medium and incubated either shaken or unshaken was also assessed. The potential environmental significance of iron-oxidizing heterotrophs in accelerating pyrite oxidation is discussed.
Journal Article↗
High-dose melphalan with autotransplantation for refractory multiple myeloma: results of a Southwest Oncology Group phase II trial.
PURPOSE: To evaluate high-dose melphalan followed by autologous stem-cell transplantation in patients with refractory multiple myeloma. PATIENTS AND METHODS: Multiple myeloma patients with alkylating agent or vincristine/doxorubicin/dexamethasone-refractory disease were eligible for the phase II multi-institutional Southwest Oncology Group trial S8993. Patients up to age 70 years were enrolled between April 15, 1991, and May 1, 1996. Patients without prior stem-cell collection were primed with high-dose cyclophosphamide (HD-CTX; 6 g/m(2)) and granulocyte-macrophage colony-stimulating factor. After stem-cell procurement, patients received melphalan 200 mg/m(2) with autologous transplantation. Upon recovery from melphalan, patients were to receive interferon alfa-2b until relapse. RESULTS: Seventy-two patients were enrolled onto S8993; five were ineligible and one received no therapy. Of the 66 assessable patients, 56 patients underwent the transplant procedure; 54 were assessable for response and 56 for toxicity. The response to HD-CTX (n = 37) included three complete remissions (CRs; 8%) and five partial remissions (PR; 14%); response to melphalan (n = 54) included 16 CRs (30%) and 19 PRs (35%), for an overall CR and >/= PR (n = 66; intent-to-treat) of 27% and 58%, respectively. Toxicities included six treatment-related deaths: two during HD-CTX and four during transplantation. The median progression-free survival (PFS) and overall survival (OS) durations on an intent-to-treat basis from transplant registration was 11 months and 19 months (95% confidence interval, 14 to 29 months), respectively. The 3-year actuarial PFS and OS rates were 25% and 31%, respectively. CONCLUSION: High-dose therapy with melphalan 200 mg/m(2) is feasible with high response rates (58% overall) and an OS of 19 months in patients with refractory multiple myeloma.
Adult↗
Initial experiences with building a health care infrastructure based on Java and object-oriented database technology.
A multi-tiered telemedicine system based on Java and object-oriented database technology has yielded a number of practical insights and experiences on their effectiveness and suitability as implementation bases for a health care infrastructure. The advantages and drawbacks to their use, as seen within the context of the telemedicine system's development, are discussed. Overall, these technologies deliver on their early promise, with a few remaining issues that are due primarily to their relative newness.
Database Management Systems↗
Creating and indexing teaching files from free-text patient reports.
Teaching files based on real patient data can enhance the education of students, staff and other colleagues. Although information retrieval system can index free-text documents using keywords, these systems do not work well where content bearing terms (e.g., anatomy descriptions) frequently appears. This paper describes a system that uses multi-word indexing terms to provide access to free-text patient reports. The utilization of multi-word indexing allows better modeling of the content of medical reports, thus improving retrieval performance. The method used to select indexing terms as well as early evaluation of retrieval performance is discussed.
Abstracting and Indexing↗
Nutrition and feeding in infants with bronchopulmonary dysplasia after initial hospital discharge: risk factors for growth failure.
OBJECTIVE: To identify nutritional risk factors for growth failure in infants with bronchopulmonary dysplasia (BPD) after initial hospital discharge, and to describe growth in and feeding concerns about these infants after discharge to the community. DESIGN: A cohort of 40 infants with BPD was followed up for 7 monthly visits after initial hospital discharge. Data on potential risk factors were gathered prospectively. SUBJECTS/SETTING: Forty infants with BPD were recruited from all 4 tertiary-level neonatal intensive care units in the Puget Sound area of Washington. Exclusionary criteria included congenital or chromosomal anomalies, grade IV intraventricular hemorrhage, and drug or alcohol exposure in utero. MAIN OUTCOME MEASURES: Growth failure defined as weight less than the 5th percentile on National Center for Health Statistics growth curves at 2 or more points in time and a decrease in weight-for-age z score during the study period. STATISTICAL ANALYSES PERFORMED: Relative risk of growth failure with exposure to each risk factor was determined. The chi 2 test was used to measure association between growth and development, and change in z scores was used to examine growth patterns. RESULTS: Growth failure occurred in 8 of 40 infants. Twenty-nine of the infants experienced a drop in weight-for-age z score from the initial to the final study visit. Growth failure was associated with low socioeconomic status (relative risk = 4.0, 95% confidence interval = 1.3, 12.6), postdischarge days of illness (relative risk = 10.5, 95% confidence interval = 1.4, 77.4) and "suspect" development (chi 2 = 7.12, P = .014). APPLICATIONS: Infants with BPD may benefit from comprehensive postdischarge nutrition and feeding therapy that includes ensuring adequate energy intake, parental support and education, and feeding evaluation and therapy.
Bronchopulmonary Dysplasia↗
Changes in left ventricular mass and volumes in patients receiving angiotensin-converting enzyme inhibitor therapy for left ventricular dysfunction after Q-wave myocardial infarction.
OBJECTIVES: We evaluated global and segmental left ventricular (LV) mass and LV mass/volume ratio in patients with LV dysfunction receiving angiotensin-converting enzyme (ACE) inhibitor therapy after acute myocardial infarction (MI). BACKGROUND: ACE inhibitors attenuate LV dilatation and compensatory hypertrophy after acute MI in animal models. However, LV remodeling in patients after acute MI has been largely defined on the basis of changes in chamber volume alone. METHODS AND RESULTS: Twenty-nine patients with LV ejection fraction <40% received the ACE inhibitor ramipril (range 2.5 to 20 mg/day) within 5 days of their first Q-wave MI. Magnetic resonance imaging was performed at baseline and at 3 months, providing global and regional LV volumes and mass from summated serial short-axis slices. Mean arterial blood pressure was unchanged from baseline to 3-month follow-up (89 +/- 10 to 92 +/- 17 mm Hg). LV mass decreased (90 +/- 25 to 77 +/- 21 gm/m2, p < 0.0005) as LV end-diastolic volumes increased (65 +/- 13 to 73 +/- 22 ml/m2, p < 0.01). Global LV mass to volume ratio decreased from 1.40 +/- 0.28 to 1.08 +/- 0.18 gm/ml (p < 0.0001), as did circumferential wall thickness to volume ratio of noninfarcted myocardium at the base of the LV (0.06 +/- 0.02 to 0.05 +/- 0.02 mm/ml, p < 0.001). LV ejection fraction increased from 35 +/- 6 to 40 +/- 9% (p < 0.001) in the presence of an increase in calculated end-systolic wall stress (185 +/- 57 to 227 +/- 54 gm/cm2, p < 0.01). CONCLUSIONS: ACE inhibitor therapy was associated with improved LV function in the face of a decrease in mass to volume ratio of the LV as well as a decrease in wall thickness to volume ratio of noninfarcted myocardium. Whether ACE inhibitor therapy had direct or indirect effects on these changes in LV mass and function are open questions that require further investigation.
Adult↗
Extraskeletal mesenchymal chondrosarcoma of the rectus sheath.
Mesenchymal chondrosarcomas (MSCs) are a rare form of chondrosarcoma which usually arise in bone. Extraskeletal chondrosarcomas constitute a minority (14-25%) of MSCs. We describe the imaging features of an extraskeletal mesenchymal chondrosarcoma that arose from the rectus abdominus muscle.
Adult↗
Case report: post-traumatic thoracolumbar pseudomeningocoele--an unusual cause of upper lumbar pain.
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Accidental Falls↗
Gadolinium-enhanced magnetic resonance angiography of renal transplants.
Our purpose was to investigate three-dimensional (3D) gadolinium-enhanced magnetic resonance angiography (Gd-MRA) in the evaluation of renal transplant arteries. Eleven MR angiography examinations were performed in nine renal transplant patients. Gd-MRA, three-dimensional phase contrast (3D-PC) post-gadolinium, and two-dimensional time-of-flight (2D-TOF) MR angiography were performed and independently reviewed by three vascular radiologists who, for each MR angiography sequence, separately graded occlusive disease in the ipsilateral iliac artery, the transplant artery anastomosis, and the transplant artery itself. The Gd-MRA and 3D-PC data were reviewed as maximum intensity projections (MIP) reconstructed in standard planes, and the 2D-TOF data were interpreted from source images. In addition, a single vascular radiologist prospectively interpreted the Gd-MRA and 3D-PC data together, hereinafter Gd/PC, from MIP reconstructions for each case. In all of these patients either surgical (n = 3) or angiographic studies (n = 8) were performed within 21 days following the MR examination, which served as a reference standard to determine sensitivity and specificity. The sensitivity/specificity for the detection of significant stenosis were as follows: Gd-MRA, 67/88; 3D-PC, 60.3/76.6; 2D-TOF, 47/81; and Gd/PC, 100/100. The kappa statistic (kappa) for interobserver agreement for the grading of stenoses by 2D-TOF, Gd-PC, and Gd-MRA was 0.48, 0.60, and 0.74, respectively. The percentage of all vascular segments seen well enough to grade (cumulative for all three observers) was 94%, 85%, and 79% for Gd-MRA, 3D-PC, and 2D-TOF, respectively. The combination of Gd-MRA and 3D-PC is a promising approach to the evaluation of transplant renal arteries.
Adolescent↗
Angiotensin-converting enzyme inhibitor therapy affects left ventricular mass in patients with ejection fraction > 40% after acute myocardial infarction.
OBJECTIVES: We tested the hypothesis that angiotensin-converting enzyme (ACE) inhibitor therapy decreases left ventricular (LV) mass in patients with a left ventricular ejection fraction (LVEF) > 40% and no evidence of heart failure after their first acute Q wave myocardial infarction (MI). BACKGROUND: Recently, ACE inhibitor therapy has been shown to have an early mortality benefit in unselected patients with acute MI, including patients without heart failure and a LVEF > 35%. However, the effects on LV mass and volume in this patient population have not been studied. METHODS: Thirty-five patients with a LVEF > 40% after their first acute Q wave MI were randomized to titrated oral ramipril (n = 20) or conventional therapy (control, n = 15). Magnetic resonance imaging (MRI) performed an average of 7 days and 3 months after MI provided LV volumes and mass from summated serial short-axis slices. RESULTS: Left ventricular end-diastolic volume index did not change in ramipril-treated patients (62 +/- 16 [SD] to 66 +/- 17 ml/m2) or in control patients (62 +/- 16 to 68 +/- 17 ml/m2), and stroke volume index increased significantly in both groups. However, LV mass index decreased in ramipril-treated patients (82 +/- 18 to 73 +/- 19 g/m2, p = 0.0002) but not in the control patients (77 +/- 15 to 79 +/- 23 g/m2). Systolic arterial pressure did not change in either group at 3-month follow-up. CONCLUSIONS: In patients with a LVEF > 40% after acute MI, ramipril decreased LV mass, and blood pressure and LV function were unchanged after 3 months of therapy. Whether the decrease in mass represents a sustained effect that is associated with a decrease in morbid events requires further investigation.
Angiotensin-Converting Enzyme Inhibitors↗