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Biomedical subjects

J F Johnson

Publications and source records attributed to J F Johnson.

At least 19 recordsLinked to original sources

Distention of the posterior urethra: association with nonneurogenic neurogenic bladder (Hinman syndrome).

In nonneurogenic neurogenic bladder (NNNB), or Hinman syndrome, a functional bladder outlet obstruction is produced by voluntary contraction of the external sphincter during voiding. To determine whether any radiographic findings are diagnostic of this condition, the authors reviewed the genitourinary images of six boys in whom NNNB was diagnosed in the past 5 years. In contrast to true neurogenic bladder, findings of elongated, trabeculated, high-volume bladders with substantial postvoid residuals, obstructive uropathy, and vesicoureteral reflux were not associated with clinical, radiographic, or urodynamic evidence of an underlying neurologic abnormality. Furthermore, four boys had distention of the posterior urethra that the authors believe is suggestive of this condition. In these patients, the posterior urethra appeared entirely normal during early voiding, but distended after contraction of the external sphincter as voiding progressed. This posterior urethral distention may worsen the symptoms of enuresis, but may also reduce or retard the damage to the proximal urinary tract.

Child

Epstein-Barr virus genotypes in AIDS-associated lymphomas are similar to those in endemic Burkitt's lymphomas.

PCR was used to screen EBV-positive lymphomas from endemic and sporadic Burkitt's lymphoma patients, including EBV-positive lymphomas derived from patients with HIV infection. Only 10% of sporadic lymphomas from either North America (1/15) or South America (2/14) were associated with the type 2 EBV strain, whereas 50% (8/16) of lymphomas from equatorial Africa and 46% (10/22) of HIV-associated lymphomas were positive for the type 2 strain. These data, in conjunction with previous reports, suggest that the proportions of strain types in Burkitt's lymphoma reflect the proportions of strain types in peripheral lymphocytes, and not simply the prevailing regional strain. The increased association of the type 2 strain in lymphocytes and lymphomas from HIV-infected individuals and from Africa may be a result of intermittent (malaria) or continuous (HIU) compromise of immune function in these populations.

Africa

Esophageal inflammation and stricture: complication of chronic granulomatous disease of childhood.

Esophagitis in children with immunodeficiency is most commonly due to opportunistic infection. The authors describe three patients with chronic granulomatous disease (CGD) of childhood who developed esophageal strictures that were believed to be complications of the primary disease. At radiologic examination, all three patients initially had a focal narrowing of the upper thoracic esophagus. Endoscopy showed no signs of opportunistic infection or Barrett esophagus. Biopsy of the strictures in two patients revealed findings consistent with CGD. In two of the three patients, inflammation extended to involve the middle and distal esophagus. Long-term response to balloon dilation was poor in the first two patients. The third patient was lost to follow-up after a partial clinical and radiographic response to dilation.

Adult

Chest tube perforation of esophagus following repair of esophageal atresia.

The two major acute thoracic complications of closed chest tube thoracostomy are pulmonary laceration and vascular compression. We have noted that closed chest tube thoracostomy can also perforate an esophageal anastomosis or myotomy site. Clinically, such a perforation produces a profuse discharge of gas and/or fluid through a chest tube positioned at the level of the anastomosis or myotomy site. Plain films demonstrate an accumulation of extrapleural gas and/or fluid adjacent to the distal portion of the chest tube. If untreated, these accumulations may form into an extrapleural abscess.

Anastomosis, Surgical

Ileocolic intussusception: extensive reflux of air preceding pneumatic reduction.

The use of an air enema for diagnosis and treatment of intussusception has recently gained popularity. The current end point for reduction is the reflux of air into the terminal ileum. The authors report three cases in which air freely refluxed into the terminal ileum without complete reduction of the intussusceptum. Thus, reflux of air alone cannot be relied on as the sole criterion for reduction. Close examination of the cecum for a persistent filling defect is imperative to exclude unsuccessful reduction.

Enema

Symptomatic hypoglycemia secondary to a glipizide-trimethoprim/sulfamethoxazole drug interaction.

Sulfonamides have been reported to augment the hypoglycemic effects of chlorpropamide, glyburide, and tolbutamide. This case report is the first to describe a possible interaction with glipizide. An 83-year-old man receiving glipizide 10 mg bid developed symptomatic hypoglycemia within three days of adding trimethoprim/sulfamethoxazole (TMP/SMX) to his regimen. All other factors, including laboratory data, dietary intake, activity level, and concurrent use of other medications, were stable and noncontributory. This patient may have been at increased risk for this interaction secondary to his age and history of alcohol abuse. The mechanism of the interaction is probably inhibition of glipizide metabolism rather than protein-binding displacement. This case suggests that, when TMP/SMX is combined with glipizide, patients should be closely monitored, especially those at high risk for hypoglycemia.

Aged

Chronic torsion of the wandering spleen.

Torsion of a wandering spleen can occasionally produce chronic disabling clinical findings that are mistaken for a variety of digestive disturbances. Since the clinical complaints are misleading, a correct and timely radiographic analysis can prevent an extensive but unnecessary pursuit of other more common conditions. Images of an ectopic, enlarged, disoriented spleen with a devitalized parenchyma and adherent pseudocapsule can quickly establish the diagnosis of chronic splenic torsion.

Chronic Disease

Ileocolic intussusception: new sign on the supine cross-table lateral radiograph.

The ability to detect ileocolic intussusception on the supine cross-table lateral radiograph of the abdomen in infants was prospectively evaluated in 12 cases (including two recurrences) over a 2-year period. The intussusceptions (including one recurrence) were directly depicted on five radiographs as a homogeneous water-density mass producing a convex interface with bowel gas at the anterior part of the abdomen. In another four patients, the intussusception produced an inappropriate craniocaudal separation of gas-filled bowel loops in the upper part of the abdomen, caudal to the liver shadow. The intussusception was prospectively recognized on the supine cross-table lateral radiograph in nine of 12 cases.

Gases

Gastric inflammatory pseudotumor in children.

Gastric inflammatory pseudotumors have radiographic, surgical, and histologic features that simulate malignant tumors. To avoid inappropriately aggressive therapy, it is important to know when to consider this diagnostic possibility preoperatively. The cases of two children with gastric inflammatory pseudotumors are presented to emphasize three findings in this entity: (a) An inflammatory pseudotumor should be considered if a gastric mass encompasses an ulcer or a confined gastric perforation. (b) Other unusual inflammatory responses associated with a gastric mass, such as sclerosing cholangitis and retroperitoneal fibrosis, should suggest the diagnosis. (c) Inflammatory pseudotumor is the most likely cause of a gastric mass in a child with Castleman syndrome.

Child

Diffuse neonatal gastric infarction.

Diffuse neonatal gastric infarction can be a devastating complication of invasion of the gastric wall and vessels by fungi colonizing the gastric mucosa. Even in the presence of extensive transmural necrosis, however, the radiographs do not necessarily show evidence of gastric mucosal abnormality. Instead, plain films and positive contrast studies may erroneously suggest a mechanical gastric outlet obstruction. Ancillary evidence of a devitalized viscus in a baby who appears to have complete gastric outlet obstruction should suggest the diagnosis of gastric infarction.

Candidiasis

Pneumatosis in the descending colon: preliminary observations on the value of prone positioning.

Prone positioning is valuable for accurate diagnosis of intramural air in the descending colon. In the supine position, partial collapse of the descending colon can minic intramural air. Conversely, complete collapse of the descending colon eliminates the interface between intraluminal and intramural air so that the recognition of intramural air is obscured. The tendency for the descending colon to distend with gas in the prone position may reduce these false positives and negatives for intramural air.

Air

Sodium dodecyl sulfate-gel electrophoresis: staining of polypeptides using heavy metal salts.

Water-soluble salts of several heavy metals were examined for their ability to stain polypeptides resolved by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Brief gel exposure (5 min or less) to cobaltous acetate or chlorides of copper, nickel, and zinc produced negatively stained protein patterns that were qualitatively indistinguishable from those of parallel gels stained with Coomassie blue R-250. Protein patterns could be visualized less than 1 min after treatment of gels with zinc chloride; the threshold of detection was estimated at about 10-12 ng protein on standard-size slab gels. Test samples including human erythrocyte membranes, sialoglycoprotein (glycophorin) extracts, and commercial molecular weight protein standards were used to establish the scope of these stains. Protein patterns visualized by the heavy metal salts were compared and contrasted with profiles seen with three widely used silver stains. Proteins from gels treated with copper or zinc chloride could be easily recovered by simple diffusion; this makes feasible both analytical and preparative electrophoretic applications of the staining procedure. A mechanism is proposed to explain the observed protein staining by heavy metal salts.

Copper

The sensitivity of plain films for detecting perforation in children with appendicitis.

The plain films of 37 patients under age 18 with surgically and pathologically proven non perforated (16/37) and ruptured (21/37) appendicitis were reviewed in order to determine the ability of the plain film to specify perforation. Perforation was suggested when one or more of the following six findings were clearly defined: 1. Acute small bowel obstruction. 2. Extraluminal gas. 3. Mass in the right lower quadrant. 4. Colon cut-off sign at the hepatic flexure. 5. Fecalith. 6. Obliteration of the pelvic fat planes. This approach resulted in a sensitivity of 80% and a specificity of 94%, with the only false positive for perforation occurring in a patient with a fecalith. In five patients, extraluminal gas produced a triangular accumulation in the right flank which could be distinguished from intraluminal bowel gas on the supine or prone film.

Adolescent

Bleomycin nodules mimicking metastatic osteogenic sarcoma.

Patients with osteogenic sarcoma are at a very high risk of developing pulmonary metastatic disease. Bleomycin has recently been reported to cause pulmonary nodules mimicking metastatic disease. Our case adds what we believe to be the first report in the pediatric literature and describes new findings that we believe are so suggestive of bleomycin nodules that immediate biopsy to exclude metastatic disease may not be necessary.

Antineoplastic Combined Chemotherapy Protocols