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Biomedical subjects

A Henschen

Publications and source records attributed to A Henschen.

At least 163 records · Page 9Linked to original sources
PubMed1976

Abnormal behaviour of proline in the isothiocyanate degradation.

It has been observed that proline residues often initiate overlaps during sequenator analysis. The cause has been shown to be an abnormally slow cleavage reaction. The kinetics of the cleavage reaction has been studied and found to obey pseudo-first-order kinetics. There are considerable differences in reaction rates depending on the position of proline in the sequence, as demonstrated for the four prolines in the N-terminal section of the H2B histone from chicken.

Amino Acid Sequence↗
PubMed1976

Carbohydrate linkage site in the beta-chain of human fibrin.

The beta-chain of fibrin was cleaved with trypsin or cyanogen bromide. Carbohydrate containing fragments were isolated by affinity chromatography on concanavalin A-agarose. The fragments were analysed for amino acid sequence and for amino and carbohydrate composition. The sequence of 21 amino acid residues around the carbohydrate attachment point was determined. The carbohydrate carrying amino acid was identified as aspartic acid/asparagine.

Amino Acid Sequence↗
PubMedDate not supplied

Antinociceptive potencies of beta-casomorphin analogs as compared to their affinities towards mu and delta opiate receptor sites in brain and periphery.

beta-Casomorphins and their analogs were tested for their opioid activities in the myenteric plexus longitudinal muscle preparation of the guinea pig ileum (GPI), the isolated mouse vas deferens (MVD), and for their affinities to mu- delta- and kappa- binding sites in rat brain membranes. C-terminal amidation of beta-casomorphin-4 and (-5) increased opioid potency in both organ preparations (GPI, MVD) and affinity to mu-binding sites in brain whereas binding to delta-sites was diminished. These beta-casomorphin-amides displayed a 2-3 times greater naloxone reversible antinociceptive effect than natural beta-casomorphins. Introduction of D-alanine at position 2 in the beta-casomorphin-amides increased potency in the GPI whereas activity in the MVD was only slightly changed. These compounds, however, showed a remarkable increase in binding to delta-sites in brain with an unaffected or slightly increased binding to mu-sites and decreased binding to kappa-sites. D-Ala2-beta-casomorphin-4 and (-5) amides were 10 times more potent antinociceptive agents than corresponding beta-casomorphin-amides. These results suggest firstly, that peripheral delta-receptors in the MVD are not as closely related to delta-binding sites at rat brain membranes as is the case with mu-receptors in the GPI and mu-binding sites, and secondly, in addition to mu-receptors, delta-receptors may be of importance in mediating antinociception.

Animals↗
PubMedDate not supplied

Expression of tyrosine hydroxylase-like immunoreactivity in cell bodies in intraocular spinal cord grafts: a comparison with classical Falck-Hillarp histochemistry.

Earlier classical monoamine fluorescence histochemical and immunohistochemical studies describing the distribution of catecholamine neurons in the central nervous system led to the conclusion that all catecholamine fibre systems in the spinal cord have a supra-spinal origin. However, recent reports describing catecholamine neurons in upper cervical segments and at the lumbosacral junction have modified this picture. Isolated intraocular grafts of spinal cord offer a possible model with which to evaluate the presence of intrinsic monoamine neurons. Using immunohistochemistry with antiserum to tyrosine hydroxylase (TH) and Falck-Hillarp fluorescence histochemistry, such grafts from lower cervical segments were found to contain TH-immunoreactive perikarya. However, it was not possible to visualize cell bodies in grafts processed for fluorescence histochemistry. These findings raise questions about the sensitivity of the monoamine fluorescence histochemical method, and about the specificity of TH-immunohistochemistry. Perhaps TH-positive, catecholamine-negative neurons are more common than previously held or alternatively, TH expression in non-catecholamine neurons is induced by perturbations such as grafting brain tissue.

Animals↗
PubMedDate not supplied

Primary structure of rat liver L-threonine deaminase.

The primary structure of rat liver L-threonine deaminase has been studied utilizing a highly purified preparation (S.A. = 940 U/mg protein) obtained from Wistar male rats. These data have been compared with the predicted sequences obtained by other Authors, showing a considerable concordance with the Noda's prediction and difference with the Ogawa's results. The FAB-MS analysis has demonstrated the presence of an acetyl group as blocking agent on the N-terminal alanine.

Amino Acid Sequence↗