Vulvar Merkel Carcinoma: A Case Report

This is a new case of Merkel cell carcinoma of the vulva. It is a rare neuroendocrine carcinoma with an aggressive behavior. Because of its rarity in this location, it is not clear whether it behaves differently from the usual neuroendocrine carcinomas of the skin. A case of a 63-year-old patient with vulvar Merkel carcinoma is presented. The clinical presentation, microscopic and immunohistochemical features, and treatment are discussed

Adjuvant radiotherapy and chemotherapy in breast cancer: 30 year follow-up of survival

BACKGROUND:The long term outcome (more than 15 years) of adjuvant treatment in patients with primary operable breast cancer has rarely been examined.METHODS:A randomised clinical trial of radiotherapy, chemotherapy (28 day cycles of cyclophosphamide, methotrexate and 5-fluorouracil) or both on women with primary operable breast cancer (n = 322) was followed-up for a median of 27 years.RESULTS:260 (81%) patients died, 204 (78%) from breast cancer. Cancer specific survival (SE) at 10 years, 20 years and 30 years was 41 (3)%, 34 (3)% and 33 (3)% respectively. Presence of more than 3 involved lymph nodes increased cancer-specific mortality (HR 1.88, 95% CI 1.34-2.63) after adjustment for age, socio-economic deprivation and adjuvant treatment. Both age (HR 1.63, 95% CI 1.19-2.22) and involved lymph nodes (HR 1.59, 95% CI 1.17-2.14) were significant predictors of all-cause mortality after adjustment for other factors. There was no significant difference in all-cause or cancer-specific survival between patients in each of the 3 treatment arms.CONCLUSIONS:The present study highlights the long term impact of node positive disease but does not indicate that any regimen was associated with significantly better long-term surviva

The role of lymphadenectomy in uterine carcinosarcomas (malignant mixed mullerian tumours): a critical literature review

Uterine carcinosarcomas are rare and highly aggressive tumours. Although surgery is the cornerstone of treatment, the extent of the procedure remains controversial. We sought to evaluate the available literature data regarding the rationale of lymphadenectomy and its possible impact on survival. A systematic Medline, PubMed and Scopus search with special focus on the publications of the last decade. Carcinosarcomas have similar clinical characteristics and behaviour with grade 3 endometrioid or aggressive variants of uterine adenocarcinoma. All studies have demonstrated that the FIGO stage of disease is the most important prognostic factor, followed by the depth of myometrial invasion, extra-uterine spread and positive peritoneal cytology. Moreover, lymph node involvement will be found in 14-38% of patients undergoing lymphadenectomy. This figure is similar to the one reported for endometrial carcinoma. Therefore, lymphadenectomy is mandatory for staging purposes. Regarding its impact on survival, the majority of studies confirm a significant survival benefit. The possible mechanisms for the improvement of survival from lymphadenectomy include removal of micro-metastatic foci, reduction of recurrence risk (removal of “target tissue”) and mechanical circumvallate of the disease. Given that 5-38% of the patients will experience local recurrence and 30-83% distant metastases, lymphadenectomy reduces the risk of the first and identifies patients in advanced stage that may benefit from adjuvant chemotherapy, aiming to reduce the second and ultimately improve overall survival. Our review data fully justifies the rationale of lymphadenectomy, which beyond staging information seems to offer a measurable survival benefit

Cloning, sequencing, characterization, and expression of an extracellular alpha-amylase from the hyperthermophilic archaeon Pyrococcus furiosus in Escherichia coli and Bacillus subtilis

A gene encoding a highly thermostable extracellular alpha-amylase from the hyperthermophilic archaeon Pyrococcus furiosus was identified, The gene was cloned, sequenced, and expressed in Escherichia coli and Bacillus subtilis. The gene is 1383 base pairs long and encodes a protein of 461 amino acids, The open reading frame of the gene was Verified by microsequencing of the recombinant purified enzyme. The deduced amino acid sequence is 25 amino acids longer at the N terminus than that determined by sequencing of the purified protein, suggesting that a leader sequence is removed during transport of the enzyme across the membrane. The recombinant alpha-amylase was biochemically characterized and shows an activity optimum at pH 4.5, whereas the optimun temperature for enzymatic activity is close to 100 degrees C. alpha-Amylase shows sequence homology to the other known alpha-amylases and belongs to family 13 of glycosyl hydrolases. This extracellular alpha-amylase is not homologous to the subcellular alpha-amylase previously isolated from the same organism

Extreme environments as a resource for microorganisms and novel biocatalysts

The steady increase in the number of newly isolated extremophilic microorganisms and the discovery of their enzymes by academic and industrial institutions underlines the enormous potential of extremophiles for application in future biotechnological processes. Enzymes from extremophilic microorganisms offer versatile tools for sustainable developments in a variety of industrial application as they show important environmental benefits due to their biodegradability, specific stability under extreme conditions, improved use of raw materials and decreased amount of waste products. Although major advances have been made in the last decade, our knowledge of the physiology, metabolism, enzymology and genetics of this fascinating group of extremophilic microorganisms and their related enzymes is still limited. In-depth information on the molecular properties of the enzymes and their genes, however, has to be obtained to analyze the structure and function of proteins that are catalytically active around the boiling and freezing points of water and extremes of pH. New techniques, such as genomics, metanogenomics, DNA evolution and gene shuffling, will lead to the production of enzymes that are highly specific for countless industrial applications. Due to the unusual properties of enzymes from extremophiles, they are expected to optimize already existing processes or even develop new sustainable technologies. © Springer-Verlag 2005

Crystallographic analysis of a thermoactive nitrilase

The nitrilase superfamily is a large and diverse superfamily of enzymes that catalyse the cleavage of various types of carbon-nitrogen bonds using a Cys-Glu-Lys catalytic triad. Thermoactive nitrilase from Pyrococcus abyssi (PaNit) hydrolyses small aliphatic nitriles like fumaro- and malononitryl. Yet, the biological role of this enzyme is unknown. We have analysed several crystal structures of PaNit: without ligands, with an acetate ion bound in the active site and with a bromide ion in the active site. In addition, docking calculations have been performed for fumaro- and malononitriles. The structures provide a proof for specific binding of the carboxylate ion and a general affinity for negatively changed ligands. The role of residues in the active site is considered and an enzymatic reaction mechanism is proposed in which Cys146 acts as the nucleophile, Glu42 as the general base, Lys113/Glu42 as the general acid, WatA as the hydrolytic water and Nζ_Lys113 and N_Phe147 form the oxyanion hole. © 2010 Elsevier Inc

Protein kinases as targets for cancer treatment

In various types of malignancies, conventional forms of therapy (surgery, radiation and chemotherapy) are often ineffective, as well as harmful. In the last few years, a convergence of scientific advances has enabled the identification of molecular targets and signaling pathways specific to cancer cells, resulting in therapies with enhanced selectivity and efficacy and reduced toxicity. Compound validation has relied on target validation first, although some of the most successful drugs often have effects outside of their postulated mechanism. Protein kinases represent such molecular targets; considerable research effort has been devoted to the development of targeted drugs that inhibit the action of pathogenic kinases, and clinical studies performed so far have validated the positive effects of kinase inhibitors for cancer treatment. In this review, the specificity, mechanism of action and antitumor activity of several new small-molecule inhibitors of tyrosine and serine/threonine kinases are discussed. © 2007 Future Medicine Ltd

High resolution structural analyses of mutant chitinase A complexes with substrates provide new insight into the mechanism of catalysis

Chitinase A (ChiA) from the bacterium Serratia marcescens is a hydrolytic enzyme, which cleaves beta -1,4-glycosidic bonds of the natural biopolymer chitin to generate di-N-acetyl-chitobiose. The refined structure of ChiA at 1.55 Angstrom shows that residue Asp313, which is located near the catalytic proton donor residue Glu315, is found in two alternative conformations of equal occupancy. In addition, the structures of the cocrystallized mutant proteins D313A, E315Q, Y390F, and D391A with octa- or hexa- N-acetyl-glucosamine have been refined at high resolution and the interactions with the substrate have been characterized. The obtained results clearly show that the active site is a semiclosed tunnel. Upon binding, the enzyme bends and rotates the substrate in the vicinity of the scissile bond. Furthermore, the enzyme imposes a critical “chair” to “boat” conformational change on the sugar residue bound to the - 1 subsite. According to our results, we suggest that residues Asp313 and Tyr390 along with Glu315 play a central role in the catalysis. We propose that after the protonation of the substrate glycosidic bond, Asp313 that interacts with Asp311 flips to its alternative position where it interacts with Glu315 thus forcing the substrate acetamido group of - 1 sugar to rotate around the C2-N2 bond. As a result of these structural changes, the water molecule that is hydrogen-bonded to Tyr390 and the NH of the acetamido group is displaced to a position that allows the completion of hydrolysis. The presented results suggest a mechanism for ChiA that modifies the earlier proposed “substrate assisted” catalysis