Radiation techniques for acromegaly

Radiotherapy (RT) remains an effective treatment in patients with acromegaly refractory to medical and/or surgical interventions, with durable tumor control and biochemical remission; however, there are still concerns about delayed biochemical effect and potential late toxicity of radiation treatment, especially high rates of hypopituitarism. Stereotactic radiotherapy has been developed as a more accurate technique of irradiation with more precise tumour localization and consequently a reduction in the volume of normal tissue, particularly the brain, irradiated to high radiation doses. Radiation can be delivered in a single fraction by stereotactic radiosurgery (SRS) or as fractionated stereotactic radiotherapy (FSRT) in which smaller doses are delivered over 5-6 weeks in 25-30 treatments. A review of the recent literature suggests that pituitary irradiation is an effective treatment for acromegaly. Stereotactic techniques for GH-secreting pituitary tumors are discussed with the aim to define the efficacy and potential adverse effects of each of these techniques

Reticular synthesis of porous molecular 1D nanotubes and 3D networks

Synthetic control over pore size and pore connectivity is the crowning achievement for porous metal–organic frameworks (MOFs). The same level of control has not been achieved for molecular crystals, which are not defined by strong, directional intermolecular coordination bonds. Hence, molecular crystallization is inherently less controllable than framework crystallization, and there are fewer examples of ‘reticular synthesis’, in which multiple building blocks can be assembled according to a common assembly motif. Here we apply a chiral recognition strategy to a new family of tubular covalent cages to create both 1D porous nanotubes and 3D diamondoid pillared porous networks. The diamondoid networks are analogous to MOFs prepared from tetrahedral metal nodes and linear ditopic organic linkers. The crystal structures can be rationalized by computational lattice-energy searches, which provide an in silico screening method to evaluate candidate molecular building blocks. These results are a blueprint for applying the ‘node and strut’ principles of reticular synthesis to molecular crystals

THE MEMBRANE TOPOLOGY OF THE RHIZOBIUM-MELILOTI C4-DICARBOXYLATE PERMEASE (DCTA) AS DERIVED FROM PROTEIN FUSIONS WITH ESCHERICHIA-COLI K12 ALKALINE-PHOSPHATASE (PHOA) AND BETA-GALACTOSIDASE (LACZ)

Jording D, Pühler A. THE MEMBRANE TOPOLOGY OF THE RHIZOBIUM-MELILOTI C4-DICARBOXYLATE PERMEASE (DCTA) AS DERIVED FROM PROTEIN FUSIONS WITH ESCHERICHIA-COLI K12 ALKALINE-PHOSPHATASE (PHOA) AND BETA-GALACTOSIDASE (LACZ). MOLECULAR & GENERAL GENETICS. 1993;241-241(1-2):106-114.The Rhizobium meliloti dctA gene encodes the C4-dicarboxylate permease which mediates uptake of C4-dicarboxylates, both in free-living and symbiotic cells. Based on the hydrophobicity of the DctA protein, 12 putative membrane spanning regions were predicted. The membrane topology was further analysed by isolating in vivo fusions of DctA to Escherichia coli alkaline phosphatase (PhoA) and E. coli beta-galactosidase (LacZ). Of 10 different fusions 7 indicated a periplasmic and 3 a cytoplasmic location of the corresponding region of the DctA protein. From these data a two-dimensional model of DctA was constructed which comprised twelve transmembrane alpha-helices with the amino-terminus and the carboxy-terminus located in the cytoplasm. In addition, four conserved amino acid motifs present in many eukaryotic and prokaryotic transport proteins were observed