Management of thyroid carcinoma invading the aerodigestive tract

OBJECTIVES: To evaluate approaches to thyroid carcinoma invading the aerodigestive tract, with particular attention to well-differentiated carcinomas. STUDY DESIGN: Retrospective review of experience with thyroid carcinoma invading the aerodigestive tract over a 20-year period at a tertiary referral hospital. METHODS: The medical records of all patients with a diagnosis of thyroid cancer treated at Emory University Hospital, Atlanta, Georgia, from 1977 through 1997 were reviewed. Multiple clinical variables were analyzed including treatment, development of recurrence, and survival. Survival and time to local recurrence were determined by Kaplan-Meier analysis, and statistical comparisons were made using log-rank analysis. RESULTS: Five hundred thirty-six cases were identified; 28 patients (5.2%) were identified with invasive disease involving the aerodigestive tract. Histologic findings at the time of invasion included 15 well-differentiated (WD) carcinomas and 13 poorly differentiated (PD) carcinomas. Eight of the 28 patients (5 WD, 3 PD) underwent surgical resection of some portion of the aerodigestive tract with curative intent. Ten patients (8 WD, 2 PD) underwent incomplete resection with tumor left adjacent to aerodigestive tract structures. All patients undergoing incomplete resection developed local recurrence. Six required salvage resection, as opposed to no recurrences in WD carcinomas following complete resection (P = .01). Survival at 5 years for WD carcinomas undergoing complete resection versus initial incomplete resection was 100% versus 50%, respectively (P = .27). CONCLUSION: Review of our experience shows that complete resection of thyroid carcinoma invading the aerodigestive tract can offer prolonged palliation, improved local control, and the opportunity for cure in selected patients.     

Phenol-degrading denitrifying bacteria in wastewater sediments

The simultaneous determination of amino and organic acids in plant tissue extracts using capillary gas chromatography is described. Plant leaves were extracted in 5% (w/v) perchloric acid and neutralized extracts were purified using C18 cartridges. The amino and organic acids in purified extracts were then converted to tert-butyldimethylsilyl (TBDMS) derivatives prior to separation and detection by capillary gas chromatography (GC) with flame ionization detection. Conditions required for optimal derivatization were investigated. Amino and organic acids were readily converted to their TBDMS derivatives using N-methyl-N-tert-butyldimethylsilyltrifluoroacetamide in dimethylformamide solvent 1:6 (v/v) with an average recovery of 90% and a reproducibility of about 5%. The characteristic [M-57] and [M-159] fragment ion of the TBDMS derivatives was confirmed using GC-MS. The proposed method was demonstrated by the determination of amino and organic acids in extracts of Acacia and Eucalyptus leaves, where detection limits were 1-20 ng.     

Three-dimensional analysis of the 16 nm urothelial plaque particle: luminal surface exposure, preferential head-to-head interaction, and hinge formation

The luminal surface of mouse urothelium in contact with the urine is almost entirely covered with plaques consisting of uroplakin-containing particles that form p6 hexagonal crystals with a center-to-center distance of 16 nm. A combination of quick-freeze/deep-etch images and our previous negative staining data indicate that the head domain of the uroplakin particle, which is exposed without an extensive glycocalyx shield, interacts closely with the head domains of the neighboring particles, while the membrane-embedded tail domains are farther apart; and that urothelial particles and plaques are not rigid structures as they can change their configuration in response to mechanical perturbations. Based on these data, we have constructed three-dimensional models depicting the structural organization of urothelial particles and plaques. Our models suggest that the head-to-head interaction may play a key role in determining the shape and size of the urothelial plaques. These models can explain many properties of urothelial plaques including their unique shape, detergent-insolubility, and morphological changes during vesicle maturation.     

Camptothecin causes cell cycle perturbations within T-lymphoblastoid cells followed by dose dependent induction of apoptosis

We have investigated the effect of the anticancer compound, camptothecin on Jurkat T-cells, a lymphoblastoid leukemic cell-line. Exposure to low concentrations led to rapid cessation of DNA (more than 95%) and RNA (more than 75%) synthesis. Perturbations to the cell cycle were observed following exposure which caused a significant accumulation of cells within G1 (P = 0.03) with a concomitant decrease in G2/M (P = 0.025). Concentrations below 0.1 microM could inhibit DNA synthesis but not induce apoptosis. Induction of apoptosis was dose dependent and could be detected as early as 3 h post exposure. The apoptotic population appeared to be derived from G1 and S-phase cells but not G2/M, coinciding with the cell cycle compartments in which DNA and RNA polymerases function. However, direct inhibition of DNA polymerase alone was not shown to be associated the induction of apoptosis or with a decrease in susceptibility to camptothecin-induced cell death. The effects of camptothecin on Jurkat T-cells and the potential mechanisms involved are discussed in the context of observations made in other transformed cell lines.