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| Untersuchte Arbeit: Seite: 13, Zeilen: 12-13, 16-28 |
Quelle: Pyronnet et al 2008 Seite(n): 2, 3, Zeilen: 2: 14ff: 3: 1ff |
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| The mechanisms whereby somatostatin receptors transduce agonist-induced messages into intracellular responses under different conditions and in different cells are complex. [...] The biological effects of somatostatin are mediated through this family of five G-protein coupled receptors [!] with a high degree of sequence similarity and [!] which have been cloned in the early 1990s. They are encoded by five separate genes, located on five different chromosomes, intronless except for sst2, which is alternatively spliced to generate two isoforms named sst2A and sst2B observed mainly in rat and mouse. They all bind natural peptides, somatostatin 14, somatostatin 28 and cortistatin with similar high affinity (nM range). Only sst5 displays a 10-fold higher affinity for somatostatin 28 (Patel, 1999). Because of naturally occurring somatostatins have short half-lives in circulation (1-3 min), synthetic derivatives have been designed to produce more stable compounds. Among the many hundreds of somatostatin analogs that have been synthesized, two analogs are in common clinical use for the treatment of patients with acromegaly and gastroenteropancreatic (GEP) endocrine tumors: octreotide and lanreotide. A third, vapreotide (Sanvar®) which has been well characterized in preclinical studies for its negative effect on cell proliferation is under clinical trials (Gonzalez-Barcena et al., 2003). | The mechanisms whereby somatostatin receptors transduce agonist-induced messages into intracellular responses under different conditions and in different cells are complex. The
biological effects of somatostatin are mediated through a family of five G-protein coupled receptors (GPCR) (sst1-sst5) with a high degree of sequence similarity (39-57 %) and [!] which have been cloned in the early 1990s. They are encoded by 5 separate genes, located on 5 different chromosomes, intronless except for sst2, which is alternatively spliced to generate two isoforms named sst2A and sst2B observed mainly in rat and mouse. They all bind natural peptides, somatostatin 14, somatostatin 28 and cortistatin with similar high affinity (nM range). Only sst5 displays a 10-fold higher affinity for somatostatin 28 (Patel 1999) (Guillermet-Guibert et al., 2005; Weckbecker et al., 2003). Because of naturally occurring [page 3] somatostatins have short half-lives in circulation (1-3 min), synthetic derivatives have been designed to produce more stable compounds. Among the many hundreds of somatostatin analogs that have been synthesized, two analogs are in common clinical use for the treatment of patients with acromegaly and gastroenteropancreatic (GEP) endocrine tumors: octreotide and lanreotide. A third, vapreotide (Sanvar®) which has been well characterized in preclinical studies for its negative effect on cell proliferation is under clinical trials (Gonzalez-Barcena et al., 2003). |
The source is not given. There are similarities in the preceding sentence (line 8-11, not given in the text above), too. Also the omitted sentence (beginning in line 13) exhibits some similarities. The unnecessary additional space character before "with a high degree of sequence" indicates the practice of copy & paste. The confusing grammar in this sentence is already given in the corresponding source text, too. |
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