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Biomedical subjects

T M Bender

Publications and source records attributed to T M Bender.

At least 19 recordsLinked to original sources
PubMed2000

Effects of luminance and resolution on observer performance with chest radiographs.

PURPOSE: To examine the combined effects of image resolution and display luminance on observer performance for detection of abnormalities depicted on posteroanterior chest radiographs. MATERIALS AND METHODS: A total of 529 radiographs were displayed on a specially constructed view box at three luminance levels (770, 260, and 85 cd/m(2)) and three resolutions (100-microm, 200-microm, and 400-microm pixels). Each image was reviewed nine times by six radiologists who participated in this study. The abnormalities included nodule, pneumothorax, interstitial disease, alveolar infiltrates, and rib fracture. Negative (normal) radiographs were also included. RESULTS: Receiver operating characteristic curves indicated that the effect of image luminance was greater than that of resolution. The detection of pneumothorax, interstitial disease, and rib fracture showed statistically significant differences (P <. 05) due to luminance. The detection of pneumothorax was the only abnormality with a statistically significant difference due to resolution. There was no evidence that luminance was related to image resolution for any of the abnormalities. CONCLUSION: At a resolution of 400-microm pixels or higher across the field of view and a luminance of 260 cd/m(2) or more, primary diagnosis with posteroanterior chest radiographs is not likely to be affected by the quality of display.

Analysis of Variance↗
PubMed1997

Esophageal atresia/tracheoesophageal fistula and associated congenital esophageal stenosis.

BACKGROUND: The association of congenital stenosis of the distal esophagus (CES) in children with esophageal atresia/tracheoesophageal fistula complex (TEF) has been described but is thought to be rare. Most reports have been of individual or small numbers of cases. OBJECTIVE: The objective of the study was to evaluate the incidence, clinical and radiographic features of CES associated with TEF, and to compare the clinical and radiographic features of CES with acquired anastomotic strictures in TEF patients. MATERIALS AND METHODS: A retrospective review was undertaken of the records and radiographs of 225 infants with primary TEF repair over a 26-year period. RESULTS: A total of 18 of 225 (8 %) cases of CES associated with TEF and 43 of 225 (19 %) cases of anastomotic strictures were identified. CES was typically a relatively long, smooth circumferential narrowing at the junction of the mid-esophagus and distal esophagus, with normal-caliber esophagus above and below; anastomotic strictures, in contrast, were focal. Diagnosis of CES was delayed in 10 cases and missed on one or more fluoroscopic studies in 14 children. Symptoms, including feeding and respiratory problems and foreign body impaction, were common in both CES and anastomotic strictures; repeated esophageal dilatations were usually necessary. Esophageal perforation complicated dilatation in 6 (33 %) young children with CES, but none of the children with anastomotic strictures (P < 0.001). CONCLUSION: CES in combination with TEF is not rare and usually produces clinical symptoms. The diagnosis may be missed or delayed unless specifically evaluated surgically and radiologically. Esophageal dilatation in CES is potentially hazardous with a high risk of perforation, especially in young children.

Dilatation↗
PubMed1994

Diagnostic power of lecithin/sphingomyelin ratio and fluorescence polarization assays for respiratory distress syndrome compared by relative operating characteristic curves.

Amniotic fluids from 328 patients were analyzed for lecithin/sphingomyelin (L/S) ratio and surfactant/albumin (S/A) ratio by fluorescence polarization. Of this group, 61 neonates showed respiratory distress syndrome (RDS) on delivery within 3 days of testing. We compared the power of the L/S and S/A in diagnosing pulmonary maturity, using relative operating characteristic (ROC) curves. The area defined by the ROC curve of the S/A test exceeded the area defined by the L/S curve, but this difference was not statistically significant. The diagnostic power of the S/A test appears to be at least equal to that of the standard L/S test. A review of five cases of RDS in which laboratory tests had suggested maturity showed that neither the L/S nor the S/A could satisfactorily resolve the problem of false interpretations of maturity, particularly in mothers with diabetes mellitus who underwent cesarean section.

Albumins↗
PubMed1993

Mechanism of c-myc regulation by c-Myb in different cell lineages.

Activation of the murine c-myc promoter by murine c-Myb protein was examined in several cell lines by using a transient expression system in which Myb expression vectors activate the c-myc promoter linked to a chloramphenicol acetyltransferase reporter gene or a genomic beta-globin gene. S1 nuclease protection analyses confirmed that the induction of c-myc by c-Myb was transcriptional and affected both P1 and P2 start sites in a murine T-cell line, EL4, and a myelomonocytic line, WEHI-3. Mutational analyses of the c-myc promoter revealed that two distinct regions could confer Myb responsiveness in two T-cell lines, a distal site upstream of P1 and a proximal site within the first noncoding exon. In contrast, only the proximal site was required for other cell lineages examined. Five separate Myb-binding sites were located in this proximal site and found to be important for c-Myb trans activation. DNA binding was necessary for c-myc activation, as shown by the loss of function associated with mutation of Myb's DNA-binding domain and by trans-dominant repressor activity of the DNA binding, trans-activation-defective mutant. The involvement of additional protein factors was addressed by inhibiting protein synthesis with cycloheximide in a conditional expression system in which the activity of presynthesized Myb was under the control of estrogen. These experiments indicate that de novo synthesis of additional proteins was not necessary for c-myc trans activation. Together these data reveal two cell lineage-dependent pathways by which c-Myb regulates c-myc; however, both pathways are mechanistically indistinguishable in that direct DNA binding by Myb is required for activating c-myc whereas neither de novo protein synthesis nor other labile proteins are necessary.

Animals↗
PubMed1991

Radiographic manifestations of anomalies of the gastrointestinal tract.

Congenital anomalies of the gastrointestinal tract can pose serious threats to the health of newborn infants and children. Perhaps nowhere has pediatric surgery had as dramatic an impact as in the care and treatment of these conditions. The pediatric radiologist works closely with the surgeon in evaluating these anomalies in young children. Plain radiographic films and contrast studies have been and remain the first step in studying these anomalies. Newer imaging modalities, however, also have made contributions to the continuing importance of the role of the radiologist in the diagnosis and care of children with these anomalies.

Digestive System↗
PubMed1991

Radiographic manifestations of anomalies of the limbs.

Limb anomalies and their commonly associated organ malformations are increasingly recognized in fetal life because of the use of high resolution real-time sonography. In most instances plain radiography establishes the diagnosis of limb anomalies shortly after birth. In some neonates the diagnosis is tentative until full skeletal maturity is attained. When evaluation of the soft tissues and unmineralized cartilage or ossification center is a prerequisite to early definitive therapy, computed tomography and magnetic resonance imaging are the procedures of choice.

Arm↗
PubMed1988

Radiologic evaluation of the diaphragm.

Recent technical advancements allow us to better evaluate the diaphragm and juxtadiaphragmatic lesions. Plain radiographs demonstrate morphology of the diaphragm in most cases. Function of the diaphragm can easily be evaluated by ultrasonography and fluoroscopy. Ultrasonography can be performed at bedside and should be used before fluoroscopy in infants and children. Ultrasonography can also demonstrate congenital anomalies of the diaphragm in utero. CT clearly discloses the underlying pathology and the extent of most juxtadiaphragmatic lesions. The newest modality, MRI, is quite promising and may become the procedure of choice for evaluation of diaphragmatic as well as juxtadiaphragmatic lesions in the very near future.

Diaphragm↗
PubMed1988

Pulmonary pseudofibrosis and pseudomass lesions.

Abnormal size and/or number of the pulmonary and bronchial vessels and lymphatics may mimic pulmonary parenchymal lesions (pseudofibrosis). Abnormalities of the central pulmonary artery, pulmonary vein, thoracic aorta, and brachiocephalic branches may mimic intrathoracic mass lesions (pseudomass lesions). Radiologists should interpret these radiographic findings in the light of other accompanying radiographic findings and the clinical presentation.

Bronchial Arteries↗
PubMed1988

Radiographic evaluation of children with urinary tract infections.

Any child with urinary tract infection needs a radiologic work-up to determine his or her potential risk for sustaining renal damage. VCUG, either fluoroscopic or isotopic, should always be performed. If the infection responds to treatment and the VCUG is normal, ultrasonography should be performed. However, when the VCUG demonstrates reflux, radionuclide scan or, less preferably, excretory urography is indicated to assess renal parenchymal damage and function. When a urinary tract infection does not respond to treatment, ultrasonography or CT scan should be obtained to check for renal or perirenal abscess. If the findings are normal, medical treatment to control the infection is indicated. Further evaluation of the urinary tract may be temporarily delayed. In an infant with urinary tract infection and sepsis, renal ultrasonography is indicated. If the sonogram is normal, VCUG can be delayed until the infant responds to medical treatment. If ultrasonography is abnormal, VCUG and radionuclide scan such as 99mtechnetium DTPA with furosemide to evaluate gross morphology and function should be obtained. Complicated medical problems, such as urinary tract infection in combination with a history of intravenous drug abuse or with findings of fever and a mass, deserve immediate evaluation with ultrasonography or CT scan. A patient with fever of unknown origin and normal urine culture should have a radionuclide scan using gallium67 citrate or indium111-tagged leukocytes, both of which can demonstrate an extrarenal or unsuspected intrarenal site of infection. A variety of imaging modalities are available today for investigating urinary tract infections in the pediatric patient. Used intelligently, singly or in combination, these examinations provide information for the clinical evaluation as well as short-and long-term management of infections, their causes and complication, and their effect on renal function.

Child, Preschool↗
PubMed1987

Pediatric chest trauma.

Blunt and penetrating chest trauma in children results from many causes but the major cause is motor vehicle accidents. The trauma induces a variety of injuries to the bony thorax, the pulmonary parenchyma, and mediastinal structures. In recent years, a disturbing increase in iatrogenic chest trauma has occurred in patients, particularly small infants, receiving intensive hospital care. Radiologic evaluation plays an important role in documenting and diagnosing these traumatic and iatrogenic injuries. The various radiologic manifestations of these injuries are described and discussed.

Child↗
PubMed1985

Transient myocardial ischemia of the newborn infant.

Ten full-term newborn infants with transient myocardial ischemia developed radiographic evidence of cardiomegaly and pulmonary venous congestion within the first few hours of life. In five patients, radiographic findings returned to normal during the first week of life. In the remaining five patients, radiographic findings improved within the second week and eventually became normal. Echocardiography done on six patients demonstrated left ventricular dysfunction in all six patients. Those infants with documented perinatal insults tend to have a protracted clinical course with eventual recovery. Pathophysiology and clinical course are discussed.

Cardiac Catheterization↗
PubMed1985

Congenital oesophageal stenosis.

Clinical and radiographic observations in 34 infants and children with congenital stenosis of the oesophagus are reported. (1) Congenital stenosis of the oesophagus occurs more frequently than the previous literature suggests. (2) A congenital stenosis most commonly affects the lower oesophagus at the junction of its middle and distal thirds. (3) High oesophageal stenosis is less common, usually producing respiratory distress. Low oesophageal stenosis is more frequent, usually producing vomiting and oesophageal obstruction at the time the patients begin eating solid foods. (4) Oesophageal stenosis persists into adult life although its clinical course is benign. (5) An infant who vomits undigested food should have an oesophagram for evaluation of possible congenital oesophageal stenosis. (6) A child who impacts a foreign body in the oesophagus, particularly in the distal half of the oesophagus, should have a follow-up oesophagram after removal of the foreign body to assess the possibility of congenital oesophageal stenosis.

Child, Preschool↗
PubMed1984

Calcified mediastinal lymph nodes in Hodgkin's disease.

Four new cases of calcified mediastinal lymph nodes in Hodgkin's Disease in children are reported. Calcifications appeared 13 months to 3 years 11 months following radiotherapy. One of the four cases continued to show a widened mediastinum despite remission. It is still to be determined if the presence of calcified mediastinal nodes in Hodgkin's disease represents a favourable prognostic sign.

Calcinosis↗