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Biomedical subjects

R Scharf

Publications and source records attributed to R Scharf.

At least 73 records · Page 4Linked to original sources
PubMed1981

[Cholecystokinin-pancreozymin synthesis. Synthesis of [28-threonine,31-norleucine]- and [28-threonine,31-leucine]cholecystokinin-pancreozymin-(25-33)-nonapeptide].

The syntheses of two analogues related to the C-terminal nonapeptide amide sequence 25-33 of cholecystokinin-pankreozymin are described. Based on the primary structure of the CCK-PZ-active caerulein and the experiences gained from the methionine replacement with leucine or norleucine in human little gastrin I, the analogues were designed by substituting methionine 28 with threonine, and methionine 31 with leucine and norleucine, respectively. Using a new method for the synthesis of tyrosine-O-sulfate-containing peptides, developed in our laboratory, and applying acid-labile side-chain protection in combination with the benzyloxycarbonyl group, the fully protected nonapeptide amide derivatives Z-Arg(Z2)-Asp(OBut)-Tyr-(SO3Ba1/2)-Thr(But)-Gly-Trp-Leu-Asp(OBut)-Phe-NH2 and Z-Arg(Z2)-Asp(OBut)-Tyr(SO3-Ba1/2)-Thr(But)-Gly-Trp-Nle-Asp(OBut)-Phe-NH2, were obtained. Upon hydrogenolytic and subsequent acidolytic removal of the protecting groups, followed by purification via chromatographic procedures the nonapeptide amides were isolated in satisfactory yields at a high degree of purity. In vivo and in vitro assays showed that a substitution of methionine 31 by norleucine with concomitant replacement of methionine 28 by threonine produced a fully active analogue, whereas for the threonine 28, leucine 31 analogue the pankreozymin-activity was lowered by a factor 10.

Amino Acid Sequence↗
PubMed1976

[Diagnosis and therapy of Crohn's disease].

Crohn's ileocolitis is an etiologically unclarified inflammatory disease of the alimentary canal, which is in most cases arranged in segments, may concern all segments, but above all may take place in the inferior ileum and the adjacent segments of the colon. The diagnosis which formerly was certainly made too infrequently is difficult, but histologically it is to be ascertained by typical granulomas of the epitheloid cells. The disease which extraordinarily often is connected with recidivations demands a consequent conservative combination therapy with salazopyrine and cortisone, in acute exacerbations and in formations of fistulae an additional prescription of bactericidal broad spectrum antibiotics is necessary. Resistent courses justify the application of immunosuppressive drugs. The indication to operation is critically to be given and to be restricted to the resection of stenosing narrowings of the lumen.

Adolescent↗
PubMed1976

[The synthesis of motilin, III: Purification and characterization of (13-norleucine) motilin and (13-leucine) motilin (author's transl)].

The preparation of the pure docosapeptide H-Phe-Val-Pro-I1e-Phe-Thr-Tyr-Gly-Glu-Leu-Gln-Arg-Nle-Glu-Glu-Lys-Glu-Arg-Asn-Lys-Gly-Gln-OH ([Nle13]motilin) and of the analogous [Leu13]motilin from the crude synthetic materials obtained after deblocking of the overall protected docosapeptide derivatives by means of trifluoroacetic acid is described. In a preliminary experiment the separation of crude [Nle13]-motilin into several components, some of which being indistinguishable by thin layer chromatography, was achieved by repeated ion-exchange chromatography on QAE-Sephadex A-25 and SP-Sephadex C-25. Subsequent characterization of some of the isolated side-products, using amino acid analysis as well as spectroscopic (UV, CD) and enzymatic methods, in comparison to the major product enabled conclusions on the reasons of their formation. The undesired formation of des-(Thr6 -Tyr7 Gly8)[Nle13] motilin and of [D-Phe5-Nle13]motilin could be avoided during the subsequent major synthesis of [Nle13] motilin and during the preparation of [Leu13] motilin by changing certain synthetic conditions and, respectively, by using a specially purified protected fragment of the sequence 1-8, being free of diastereomers. Single ion-exchange chromatography on SP-Sephadex C-25 was sufficient for the purification of the so obtained crude synthetic end-products.

Amino Acids↗