The consultants concur that distal tracheal stenosis is a challenging problem in the pediatric patient but don't all agree on the presentation or management. Drs. Cotton and Crysdale agree that these children are usually seen with biphasic stridor. Dr. Parsons believes that biphasic stridor is not particularly common but inspiratory stridor is. The experts divide the differential diagnosis into intrinsic and extrinsic categories. Dr. Cotton lists tracheomalacia, complete tracheal rings and masses, such as an isolated hemangioma or granuloma. The usual extrinsic lesion is a vascular anomaly, the most common being an innominate artery. Dr. Crysdale's differential diagnosis includes tracheal stenosis, either congenital or acquired, and tracheomalacia. Vascular compression is most common as an extrinsic cause. Dr. Parsons includes tracheomalacia, complete tracheal rings, segmental tracheal stenosis, isolated masses, and vascular anomalies, such as an aberrant innominate artery. He also states that a tracheoesophageal fistula must be considered. Dr. Cotton prefers MRI and possibly a barium swallow for assessing vascular architecture. Even finding an air bronchogram on a chest x-ray can pinpoint an area of stenosis. The best test is direct laryngoscopy with video-photography. While Drs. Parsons and Crysdale agree that direct laryngoscopy is the best, Dr. Crysdale also suggests MRI or CT and adds that a contrast bronchogram is a most useful test.(ABSTRACT TRUNCATED AT 250 WORDS)

Airway Obstruction↗

PubMedDate not supplied

Nasal mass in a pediatric patient.

The consultants agreed that the differential diagnosis should focus on congenital masses, including an encephalocele, glioma, dermoid, hamartoma, hemangioma, rhabdomyosarcoma, neurofibroma, and nasolacrimal duct cyst. There was some disagreement as to which is the best way to evaluate the mass, ranging from an MRI (Dr. Reilly), to CT scan (Dr. Cotton), to both MRI and CT (Dr. Koopman). Blood tests to evaluate pituitary function could be indicated if there was a sphenoid defect (Dr. Reilly). None of the experts would biopsy this lesion. All would proceed with a definitive resection. One surgeon would defer surgery for several months and then perform the resection via a biocoronal craniotomy (Dr. Reilly). A combined anterior craniotomy and external ethmoidectomy would be planned by another (Dr. Koopman). The third consultant would combine an anterior craniotomy with a mid-face degloving, external rhinoplasty, or lateral rhinotomy approach (Dr. Cotton). Routine perioperative antibiotics would only be used by two of the surgeons (Drs. Reilly and Koopman). If a CSF leak were encountered there are several options. A small lesion could be allowed to close on its own (Dr. Reilly). If the leak occurred while the bicoronal incision was still open or if the leak were large, it could be repaired from above (Drs. Reilly and Koopman). One surgeon would proceed with a repair from above even if the leak were encountered during the intranasal approach (Dr. Cotton). Only one surgeon would restrict postoperative activity with intubation and sedation or paralysis (Dr. Koopman). Regarding follow-up, no one was concerned about the final pathology report.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain↗

PubMedDate not supplied

Construction of protein analogues by site-specific condensation of unprotected fragments.

The extreme sensitivity to periodate of 1-amino, 2-hydroxy compounds permits the selective conversion of N-terminal serine and threonine to an aldehydic group. We have used this reaction to construct analogues of human granulocyte colony stimulating factor (G-CSF) by allowing such oxidized peptides to react with others that have had a hydrazide derivative attached to the C-terminus by reversed proteolysis. Two recombinant analogues of G-CSF were used as starting materials. Both had only a single lysine residue (at position 62 and 75, respectively) followed immediately by a serine. Digestion of each analogue by the lysine-specific protease from Achromobacter lyticus gave two fragments, one of which could be N-terminally oxidized and the other converted to the C-terminal hydrazide derivative by reversed proteolysis using the same enzyme. After preliminary studies with model peptides, we first reacted the corresponding peptide pairs together and then, in order to eliminate the 64-74 disulfide loop, fragment 1-62 from the first analogue with fragment 76-174 from the second. Reactions are efficient (up to 80% product based on the oxidized fragment) and take place under very mild conditions. The hydrazone bond can easily be stabilized by reduction with NaBH3CN. This method represents a new, reasonably general route for the construction of large protein chimeras of precisely controlled structure.

Amino Acid Sequence↗

PubMedDate not supplied

Site-specific religation of G-CSF fragments through a thioether bond.

A new approach is described for linking, through a thioether bond, the C-terminus of one unprotected polypeptide with the N-terminus of another. Homocysteine thiolactone is attached to the C-terminus of one polypeptide by reverse proteolysis and provides through hydroxylamine treatment a free sulfhydryl group. The alpha-amino group of a second polypeptide is selectively iodoacetylated by reaction with iodoacetic anhydride at pH 6.0 or the N-hydroxysuccinimide ester derivative at pH 7.0. Coupling of the two modified fragments occurs in a spontaneous alkylation reaction under mild conditions. After preliminary experiments with small peptides, this approach was extended to large protein fragments derived from recombinant analogs of G-CSF by enzymatic digestion. This approach provides a means of making head-to-tail protein chimeras or introducing noncoded structural elements into a protein.

Acetylation↗

PubMedDate not supplied

Surgical correction of subglottic stenosis of the larynx in infants and children. Progress report.

Explore the source record for details and available documents.

Animals↗

PubMedDate not supplied

Esophageal papillomatosis: case report.

An unusual case report of asymptomatic multiple esophageal papillomas associated with pedunculated hypopharyngeal papillomas that presented as laryngeal obstruction in a 2 1/2-year-old boy who underwent resection and irradiation of a retroperitoneal neuroblastoma at the age of nine months. Barium swallow and esophagoscopy confirmed the presence of multiple asymptomatic lesions involving the upper two-thirds of the esophagus. Biopsy confirmed the hypopharyngeal and esophageal lesions to be similar in nature.

Airway Obstruction↗

PubMedDate not supplied

Management of subglottic stenosis in infancy and childhood. Review of a consecutive series of cases managed by surgical reconstruction.

The management of mature subglottic stenosis secondary to endotracheal intubation in infancy and childhood remains a controversial issue. If treated similarly to congenital subglottic stenosis by tracheotomy and a "wait-and-see" period then there is a considerably higher mortality and morbidity for the acquired disease compared with the congenital. Eighteen children with severe acquired subglottic stenosis managed by surgical reconstruction are presented; 17 have been successfully extubated. The longest follow-up is 5 1/2 years. No evidence of interference with laryngeal growth is evident.

Adolescent↗

PubMedDate not supplied

Protrusion of the laryngeal ventricle in a pediatric patient following nasotracheal tube intubation.

Nasotracheal intubation has been well established as a method for maintaining an artificial airway in children. Approximately 0.5% to 1.0% of cases have complications that require surgical intervention to correct the laryngeal trauma. A complication described as protrusion of the laryngeal ventricle following nasotracheal intubation is reported. The clinical presentation and a rationale for the treatment plan are discussed.

Child↗