Synthesis of Cyclic Peptide Mimetics by the Successive Ring Expansion of Lactams.

A successive ring-expansion protocol is reported that enables the controlled insertion of natural and non-natural amino acid fragments into lactams. Amino acids can be installed into macrocycles via an operationally simple and scalable iterative procedure, without the need for high dilution. This method is expected to be of broad utility, especially for the synthesis of medicinally important cyclic peptide mimetics.

Cervical thoracic duct cyst: Importance of preoperative suspicion for appropriate management of left-sided neck mass.

Cervical thoracic duct cysts occur infrequently but are an important consideration when evaluating cystic supraclavicular masses. Only 22 cases have been reported to date. We review the clinical presentation, evaluation, and treatment of 2 cases of large thoracic duct cysts treated with surgical resection. A high suspicion of thoracic duct cyst based on location, radiographic findings, and fine-needle aspiration results is sufficient evidence for recommendation of surgical excision. However, enlarged cysts, as noted in our cases, can obliterate or attenuate the thoracic duct, making it difficult to identify intraoperatively. A high suspicion of thoracic duct cyst is important for identifying and ligating the duct to prevent complications such as chyle leak or chylothorax.

Intraoperative parathyroid hormone assay: a necessary tool for multiglandular disease.

OBJECTIVES: The aims were to: (1) evaluate whether failure of intraoperative parathyroid hormone (ioPTH) to decrease by the Miami criterion is a more specific indicator of multiglandular disease (MGD) than sestamibi scan and (2) determine an adequate cutoff value for decrease in ioPTH in MGD. STUDY DESIGN: Case series with chart review. SETTING: Louisiana State University Health Sciences Center- Shreveport. SUBJECTS AND METHODS: Review of subjects undergoing parathyroidectomy using ioPTH and sestamibi for suspected parathyroid adenoma between 2005 and 2009. Patients with MGD were identified by pathology and operative reports. RESULTS: Eighty-three subjects were identified (68 single adenomas, 11 double adenomas, and 4 multiple-gland hyperplasias). Sestamibi predicted MGD in only 4 of 15 cases (27%). Five of the 11 double adenomas (DAs) were identified during initial surgery; the rest required reoperation for cure. ioPTH was useful in predicting MGD in 7 of 10 cases (70%) when a postexcisional value was drawn after removal of the first enlarged gland. Using the Miami criterion of 50% decrease in ioPTH over 15 minutes would have resulted in 1 unnecessary neck exploration and 3 missed DAs. Requiring both a 50% decrease in ioPTH over 15 minutes and normalization of the postexcisional value would have missed only 1 DA and resulted in a single unnecessary neck exploration. CONCLUSION: Sestamibi alone fails to identify MGD 73% of the time, but the success rate increases significantly when combined with ioPTH. The "50% and normal" criterion worked best to increase the success rate in our study population, but larger trials are needed to confirm the utility of this criterion.

Tracheal non-Hodgkin's lymphoma masquerading as benign granulation tissue: a report of two cases.

Primary tracheal non-Hodgkin's lymphoma (NHL) is rare, with fewer than 30 cases reported to date. We review the clinical presentation, evaluation, and treatment of 2 cases of tracheal NHL mimicking granulation tissue. The first patient was a 67-year-old man with myelodysplastic syndrome and Crohn's disease who had a recurring lesion of the proximal trachea causing significant airway obstruction. The second patient was a 47-year-old man with a history of multiple intubations who presented with dyspnea and stridor due to circumferential tracheal stenosis. In both cases, bronchoscopy revealed abundant granulation tissue, and the initial biopsy results indicated benign disease. However, after requests from the diagnostic team to rule out lymphoma, additional immunohistochemical stains and polymerase chain reaction testing confirmed NHL. Radiotherapy was initiated. The first patient responded well and remains disease-free after 4 years. The second patient died of airway obstruction due to severe distal tracheal stenosis. Recurrent granulation tissue should raise the suspicion of malignancy and prompt further tissue evaluation for evidence of lymphoma. Steroids for airway compromise may cause progression to mature stenosis as prednisone is used in the treatment of lymphoma. Localized disease involving the central airways may be treated successfully with limited chemotherapy and radiotherapy.