Excretory urography in the emergency department: utility of teleradiology

To test the feasibility of teleradiology for use with excretory urograms obtained in the emergency department in cases for suspected renal colic, radiographs from 43 patients were digitized, transmitted via standard phone lines, and viewed on a video monitor 2 miles distant. Diagnostic interpretations of the video image and the original radiograph were reviewed for degree of concordance. The video and film images of the 27 examinations showing obstruction were interpreted with 100% correlation. Agreement as to the site of obstruction was present in 93% of cases. Only two-thirds of renal and ureteral calculi seen on the radiographs were discerned on the video images, however. Teleradiology proved as useful for ongoing monitoring and modification of these examinations as for initial interpretation.     

Expression of sodium channel subtypes during development in rat skeletal muscle.

This study contrasts the developmental patterns of expression of 2 subtypes of the voltage-dependent sodium channel in rat muscle that are differentiated by their immunoreactivity with monoclonal antibodies raised to the purified muscle sodium channel protein. One subtype is found in the transverse tubular (T) system of slow twitch fibers as well as the plasma membrane of fast and slow twitch fibers in the anterior tibial and soleus muscles. The second is present in the plasma membrane in all fibers of both muscles. The transverse tubular subtype exhibits 2 immunocytochemical staining patterns within muscle fibers, reticular and homogeneous, which may represent labeling of the developing T tubular system and of a cytoplasmic pool of alpha subunits of the sodium channel respectively. The reticular pattern eventually disappears in fast twitch fibers but persists into the adult stage in slow twitch fibers. The homogeneous pattern is also seen with antibodies to the plasma membrane subtype and disappears in early development as immunoreactivity to both subtypes gradually appears in the surface membrane. A reticular pattern is never seen with the plasma membrane subtype. The factors that modulate the expression of these subtypes is unknown.     

Localization of sodium channel subtypes in adult rat skeletal muscle using channel-specific monoclonal antibodies

Five monoclonal antibodies specific for the 260 kDa subunit of the rat skeletal muscle sodium channel were used to probe the distribution of this channel in adult muscle. All the antibodies reacted with the surface membrane of fast- and slow-twitch fibers in the rat anterior tibial and soleus muscles. Immunoreactivity was also present in the endplate region; this was significantly more intense than that in the surrounding extrajunctional membrane. At the electron microscopic level, this junctional immunoreactivity could be traced uniformly throughout the secondary folds of the post-synaptic membrane. Three of the monoclonal antibodies (A/B2, F/E4, and I/E3) exhibited an additional distinct immunoreactivity pattern, staining the interior of selected fibers in the anterior tibial muscle that were subsequently identified as slow-twitch fibers. An identical reactivity pattern was observed with most of the soleus muscle fibers. In longitudinal sections of slow fibers examined at the light microscopic level, transversely oriented, regularly spaced doublets of fluorescence were localized at the junction of the A and I bands in each sarcomere. In permeabilized slow fibers exposed to A/B2 and examined at the electron microscopic level, internal reactivity was associated exclusively with the membranes of the T-tubular system. A/B2 also strongly stained a transversely oriented pattern within cardiac muscle fibers exhibiting the characteristics of the T-tubular system in that tissue. We conclude that at least 3 subpopulations of sodium channels are present in adult skeletal muscle: those in the sarcolemma of fast and slow fibers, those in slow-twitch fiber T-tubular membranes, and those in the T-tubular system of fast fibers. The channels in the slow fiber T-system apparently share common epitopes with those in the T-system of cardiac fibers.     

Bronchopulmonary dysplasia: radiographic appearance in middle childhood

Chest radiographs were compared for three groups of children 8-9 years old: 23 survivors of bronchopulmonary dysplasia (BPD), 33 survivors of hyaline membrane disease without BPD, and 35 survivors of premature birth without neonatal respiratory problems. Only four children in the second group and three in the third had abnormal lungs. Linear shadows, apparently representing strands of fibrosis or deep pleural fissuring, were seen more frequently (15 of 23) in the BPD group than in the others (P less than .0001). Seventeen children in the BPD group had definite pulmonary abnormalities, none of them severe. The anteroposterior dimension of the chest in survivors of BPD tended to be decreased (P less than .001 vs that of reported control subjects).