[Two case report of papillary carcinoma of thyroglossal duct cyst]

Thyroglossal duct carcinoma is a rare midline neck carcinoma that is usually diagnosed postoperatively. Its incidence is about 1-1.5%. This article presents two cases of thyroglossal duct cyst carcinoma and their diagnosis and the management methods are described. Our patients were 24 and 16 year old ladies that referred to Khalili hospital with chief complaint of midline neck mass in 1379, 1377. Their para-clinical tests were negative for malignancy but papillary carcinoma was detected after surgery. They have only been followed up for few years without any thyroidectomy and radioiodine therapy. There is high false negativity in fine needle aspiration and sonography for ruling out malignancy in thyroglossal cyst; therefore, para clinical tests cannot rule out malignancy and excisional biopsy is the only definite way for ruling out thyroglossal cyst carcinoma. On the other hand, severe controversy exists in managing of thyroglossal cyst carcinoma. While some surgeons are interested in total thyroidectomy and radioiodine ablation, it is not necessary to do thyroidectomy if the thyroid gland, lymph nodes and excised mass margins are free of malignancy because excellent prognosis of thyroglossal cyst carcinoma and probable thyroid involvement can be found by close follow up

Cloning and expression of SAT-3 involved in SA-Le(x) biosynthesis: inhibition studies with polyclonal antibody against GST-SAT-3 fusion protein.

The SAT-3 activity (CMP-NeuAc:Gal beta 1-4GlcNAc beta 1-3 Gal beta 1-4Glc-ceramide alpha 2-3 sialytransferase) involved in the biosynthesis of sialy Le(x) has been characterized in human colon carcinoma cells and embryonic chicken brains. Using RT-PCR-based strategy, we have isolated partial cDNA clones of SAT-3 from ECB and Colo-205 mRNAs. Suitable primers from sialylmotif and N-terminal sequence of human placenta SAT-3 (HP-SAT-3) were used. The 800 bp cDNA fragment encoding a region (90%) of alpha 2-3 sialyltransferase (SAT-3) catalytic domain from ECB has been expressed as a glutathione S-transferase (GST) soluble fusion protein (62 kDa) in E. coli and purified over glutathione-agarose affinity matrix. Polyclonal antibody has been produced against affinity-purified catalytic domain of SAT-3 (GST-SAT-3 fusion protein). A concentration-dependent polydonal antibody binding to native SAT-3 has also been demonstrated by measuring the residual SAT-3 activity in the enzyme fractions from Colo-205. The marked inhibition (> 80%) of SAT-3 activity and relatively less inhibition (< 20%) of SAT-4 activity (CMP-NeuAc:GgOse4Cer alpha 2-3sialyl transferase) suggests strongly the existence of two different gene products (SAT-3 and SAT-4) in human colon carcinoma Colo-205 cells and in embryonic chicken brains (ECB).

Ceramide glycanase from rat mammary tissues: inhibition by PPMP(D-/L-) and its probable role in signal transduction.

A ceramide glycanase (CGase activity has been characterized from lactating rat mammary tissue which cleaves the glycosidic bond between sphingosine and the glucose chain of a glycosphingolipid (GSL) thus liberating the intact oligosaccharide chain from a GSL. The majority (65%) of the hydrolase activity was detected in the supernatant fraction when the rat mammary tissue homogenate was centrifuged at 100,000 x g. Attempts to purify the enzyme indicated that the CGase protein is of hydrophobic nature as it binds to hydrophobic columns. The enzyme has been partially purified using hydrophobic columns in tandem. The partially purified protein was found to be immunoreactive to the antibody raised against the purified clam CGase. The immunostained band corresponded to a 64 kDa protein as also found with the clam enzyme. This immuno cross-reactivity indicated probable structural similarities between CGase proteins isolated from widely separated species in the evolutionary tree. The rat CGase was found to have a specific detergent requirement for optimal activity, and the pH optimum was found to be between 5 and 6. The enzyme activity is partially heat stable. It is not a divalent cation requiring enzyme; however, the activity is totally inhibited in the presence of mercury, indicative of a sulfhydryl group in the active site of the enzyme. The rat mammary CGase activity is inhibited in the presence of both D- and L-PPMP (1-phenyl-2-hexadecanoylamino-3-morpholino-1-propanol. HCl), homologs of PDMP (1-phenyl-2-decanoylamino-3-morpholino-1-propanol. HCl), a well-known inhibitor of GlcT-1 (Ceramide: UDP-Glc Glucosyltransferase), an enzyme in the glycolipid synthetic pathway. The inhibition seems to be of a competitive nature and the same type of inhibition is also observed with clam CGase. The CGase activity was found to be highest in lactating tissue compared to the activity found in either pregnant or post-lactating rat mammary tissues. Tissue survey indicated the presence of high levels of CGase in lactating rat liver, uterus, and ovary; moderate activity was detected in kidney and spleen. Both virgin and male rat mammary tissue also indicated a basic level of CGase activity. However, newborn spleen and mammary tissue showed a comparable level of activity to that found in lactating rat tissues. This report is mainly concerned with the characterization of CGase activity from a mammalian source and its importance in cellular processes.