Biomedical subjects
Publications and source records attributed to B R Parker.
We have presented an unusual case of chondroblastoma mimicking a malignant tumor. Retrospective review of radiographs obtained 19 years before the diagnosis gave us a unique opportunity to follow the natural history of this atypical lesion.
BACKGROUND: Bronchopulmonary dysplasia is a chronic lung disease that often develops after mechanical ventilation in prematurely born infants with respiratory failure. It has become the most common form of chronic lung disease in infants in the United States. The long-term outcome for infants with bronchopulmonary dysplasia has not been determined. METHODS: We studied the pulmonary function of 26 adolescents and young adults, born between 1964 and 1973, who had bronchopulmonary dysplasia in infancy. We compared the results with those in two control groups: 26 age-matched adolescents and young adults of similar birth weight and gestational age who had not undergone mechanical ventilation, and 53 age-matched normal subjects. RESULTS: Sixty-eight percent of the subjects with bronchopulmonary dysplasia in infancy (17 of the 25 tested) had airway obstruction, including decreases in forced expiratory volume in one second, forced expiratory flow between 25 and 75 percent of vital capacity, and maximal expiratory flow velocity at 50 percent of vital capacity, as compared with both control groups (P less than 0.0001 for all comparisons). Twenty-four percent of the subjects with bronchopulmonary dysplasia in infancy had fixed airway obstruction, and 52 percent had reactive airway disease, as indicated by their responses to the administration of methacholine or a bronchodilator. Hyperinflation (an increased ratio of residual volume to total lung capacity) was more frequent in the subjects with a history of bronchopulmonary dysplasia than in either the matched cohort (P less than 0.0006) or the normal controls (P less than 0.0004). Six of the subjects who had bronchopulmonary dysplasia in infancy had severe pulmonary dysfunction or current symptoms of respiratory difficulty. CONCLUSIONS: Most adolescents and young adults who had bronchopulmonary dysplasia in infancy have some degree of pulmonary dysfunction, consisting of airway obstruction, airway hyperreactivity, and hyperinflation. The clinical consequences of this dysfunction are not known.
Explore the source record for details and available documents.
Proper therapy for Hodgkin disease requires accurate staging of the disease. We compared the value of CT and lymphography with that of laparotomy for staging newly diagnosed Hodgkin disease in 46 children. The laparotomy revealed disease in one or more subdiaphragmatic sites in 46%. Correlation of the imaging studies with the laparotomy findings showed that lymphography has a greater sensitivity (80%) than does CT (40%) in detecting retroperitoneal lymph nodes. The sensitivity of CT in detecting splenic involvement was only 19%, presumably because of the small size of tumor deposits in involved spleens. Staging laparotomy altered the clinical stage in 37% of children, which resulted in a significant change of therapy in those patients. Although lymphography and, to a lesser degree, CT are useful for staging of Hodgkin disease, laparotomy continues to be the most important tool in choosing appropriate therapy for children with Hodgkin disease.
Explore the source record for details and available documents.
Lesch-Nyhan syndrome is a rare X-linked recessive disorder of purine metabolism associated with a virtually complete deficiency of the enzyme hypoxanthine-guanine phosphoribosyl-transferase (HPRT). The disease is characterized by hyperuricemia, self-multilation, choreoathetosis, spasticity, and mental retardation. The abnormalities of purine metabolism are present at birth and may lead to uric acid crystalluria and stone formation early in life. Radiographic findings described in Lesch-Nyhan syndrome include faintly radio-opaque stones on abdominal radiographs or, if renal disease is present, small kidneys with poor function on intravenous urogram. Radiolucent stones are usually composed of uric acid; however, several cases of xanthine and hypoxanthine-containing calculi in Lesch-Nyhan patients receiving allopurinl therapy have also been described. Oxypurine is the collective name for the compounds hypoxanthine, xanthine, and uric acid, and all may be radiolucent. We report a case of Lesch-Nyhan syndrome with presumed renal parenchymal oxypurine deposition demonstrated readily by ultrasonography but not detected on standard radiographs or intravenous urograms.
A dynamic probabilistic model based on hazard rate analysis, Monte Carlo modeling, and lead-time estimation techniques was developed to determine the optimal timing and frequency of chest radiography in the monitoring for relapse of children with treated Hodgkin disease. The analysis incorporates the performance characteristics of chest radiography, the natural history of the disease process, and therapeutic efficacy as a function of earliness of detection in the determination of optimal strategy. Examples of the model applied to the experiences of Stanford Medical Center and St. Jude Children's Research Hospital illustrate the utility of such a model in customizing an optimal monitoring strategy for a specific institution and clinical experience. The results suggest that monitoring protocols significantly overutilize chest radiography in the evaluation for recurrent Hodgkin disease in children.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The goal of any social/health intervention program is to improve the lot of the people it is designed to serve. Of critical importance is the development and implementation of programs able to achieve such a goal is evaluation research (ER)--a process representing an interface between the generic notion of evaluation and the rigor of social research methodology. The evaluation researcher should be familiar with, and be capable of using, any of a number of (statistical and non-statistical) data-analytic techniques. The objectives of this discussion, therefore, are to (1) identify, categorize, and briefly describe statistical and other data-analytic techniques of potential use to the evaluation researchers; and (2) identify currently available resources, i.e., texts, books of readings, monographs, etc., that offer discussions and analyses of these techniques. It is hoped that such an exposition will lead to a wider understanding, acceptance, and use of these procedures, which can only enhance the quality of subsequent program policy- and decisionmaking.
Policy problems in the health and public sectors are quickly assuming a new level of complexity. Thus, the health/public sector analyst is being confronted with the task of identifying, formulating, evaluating, and making choices among larger and more complicated sets of decision alternatives. Given the context of such decisions, less-than-effective choices could adversely affect the health and social well-being of whole sections of a population. What seems to be needed, therefore, is an approach that would provide system and objectivity to the policy-making process. The use of quantitative techniques, so long applied to problems in the private and industrial sectors, would be the mainstay of such an approach. It is the goal of this article, therefore, to identify, classify, and briefly describe elements of the emerging set of materials (texts, edited readings, and monographs) which offer discussions of these techniques as they apply to problems in the health and public sectors. It is hoped that such a presentation will hasten the application of available analytic decision tools to the policy/decision problems of the public sector.
Explore the source record for details and available documents.
Large pleural effusion as the presenting feature of coccidioidomycosis in childhood has not previously been reported and may cause significant diagnostic difficulty. Three children are described who required prolonged hospitalization and therapy with amphotericin B. Primary coccidioidomycosis should be included in the differential diagnosis of large pleural effusions in pediatric patients who have been in the endemic area. Such effusions suggest a severe form of the disease and may represent evidence of acute dissemination.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Experience with 193 children 15 years of age or less who were referred for pedal lymphography over the past 11 1/2 years was reviewed. Successful bilateral lymphatic cannulation was obtained in 94% of cases; in only 2% was the study a bilateral failure. No significant complications or permanent sequelae were encountered. Lymphographic-histologic correlation in 94 children yielded an overall accuracy rate of 95% (specificity, 99%; sensitivity, 80%). Interpretative aspects were similar to that in adults; however, the frequent presence of reactive hyperplasia in childhood was noted. These results suggest that lymphography can be successfully and safely performed in children and that its diagnostic accuracy is at least as high as in adults.
A case is presented of massive air embolism complicating respiratory distress syndrome of the newborn. This uncommon complication of respiratory therapy has occurred only with high inflation pressures and has been uniformly fatal in this and all reported cases. Antemortem radiographs are necessary for accurate diagnosis.
The pretreatment roentgenographic evaluation of 105 consecutive patients less than 16 years of age with Hodgkin's disease was reviewed. The patients were divided into groups aged 1-10 years (37%) and 11-15 years (63%). All patients had chest roentgenograms, of which 36% were abnormal in the younger group and 77% abnormal in the older group. Full-lung tomography was helpful only when the chest film was abnormal or equivocal. Foot lymphography was performed in 103 patients with 20% positive for Hodgkin's disease. Lymphographic-histologic correlation was 98% in the 62 patients undergoing laparotomy. Routine skeletal surveys, as well as examinations of the urinary tract and gastrointestinal tract, were not rewarding.