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Biomedical subjects

B R Parker

Publications and source records attributed to B R Parker.

At least 19 recordsLinked to original sources
PubMed1995

Evolving asymmetric hypertrophic pyloric stenosis associated with histologic evidence of eosinophilic gastroenteritis.

The most frequently occurring and important cause of gastric outlet obstruction in the neonate and young infant is infantile hypertrophic pyloric stenosis (IHPS). A reported association of IHPS and eosinophilic gastroenteritis [1] raises interesting questions about the possible etiologic relationship between the two entities. It is plausible that the observed sonographic pyloric muscular wall thickness in IHPS may in part be dependent on the degree and duration of an allergic gastroenteropathy. A recent report suggests that endoscopy may be a more reliable diagnostic method than sonography in the patient with evolving IHPS [2]. Our recent experience with a patient with evolving IHPS supports the findings described in these prior reports.

Eosinophilia↗
PubMed1991

Case report 663. Unusual chondroblastoma of the scapula.

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.

Adult↗
PubMed1990

Late pulmonary sequelae of bronchopulmonary dysplasia.

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.

Adolescent↗
PubMed1990

Staging of Hodgkin disease in children: comparison of CT and lymphography with laparotomy.

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.

Adolescent↗
PubMed1989

Renal oxypurine deposition in Lesch-Nyhan syndrome: sonographic evaluation.

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.

Allopurinol↗
PubMed1989

Dynamic probabilistic model for determination of optimal timing of surveillance chest radiography in pediatric Hodgkin disease.

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.

Child↗
PubMed1988

Juvenile xanthogranuloma of the kidney.

Juvenile xanthogranuloma is a benign histiocytosis of infancy and childhood characteristically involving the skin, the eye, and, rarely, the lungs, liver and mesothelial structures. This report documents the first known case of renal involvement which is demonstrated by ultrasound and computed tomography.

Granuloma↗
PubMed1987

Pyelocalyceal diverticula in the Beckwith-Wiedemann syndrome.

A case of pyelocalyceal diverticula in a patient with the Beckwith-Wiedemann syndrome is presented. The abnormalities were first identified on screening ultrasound and confirmed at excretory urography. The diverticula in this syndrome are likely secondary to hereditary embryopathy of the kidneys.

Beckwith-Wiedemann Syndrome↗
PubMed1985

Diagnostic ultrasound in pediatric oncology.

Sonography is an extremely versatile diagnostic tool for the assessment of cancer in children, offering several advantages over other imaging modalities, chief of which is its truly noninvasive nature. In view of the available comparative studies and the risk/benefit and cost/benefit ratios of the imaging procedures available, ultrasound is attractive for use as the initial study of many pediatric mass lesions. Its availability, ease of application, and lower cost also favor its use in the assessment of the child with known or suspected malignancy.

Abdomen↗
PubMed1985

Heuristic approaches to decision-making in the delivery of primary health care within developing regions.

The delivery of primary health care (PHC) services is now recognized as a crucial element in the development of low-income regions. Effective delivery of these services requires the ability to solve a variety of policy decision problems. Research has demonstrated the utility of operations research/management science (OR/MS) models and methodologies in the analysis and solution of such problems. However, this approach may be limited in some regions by the data and computational requirements of the models. Intuitive approaches in the spirit of OR/MS models, termed heuristics, can provide an effective alternative in such cases. The current paper proposes a general heuristic procedure for solving problems of PHC delivery in developing regions. The heuristic is applied, in detail, to the problem of identifying "best" community financing schemes for PHC services in low-income sections of Rio de Janeiro, Brazil.

Decision Making↗