PubMed Health⌕ Search

Biomedical subjects

H Aschauer

Publications and source records attributed to H Aschauer.

At least 55 records · Page 3Linked to original sources
PubMed1985

Solid-phase synthesis of PYLa and isolation of its natural counterpart, PGLa [PYLa-(4-24)] from skin secretion of Xenopus laevis.

From the nucleotide sequence of clones isolated from a cDNA library constructed from skin of Xenopus laevis, the existence of PYLa, a peptide comprised of 24 amino acids, was predicted. This peptide was synthesized by solid-phase methods and purified to homogeneity with an overall yield of 61%. The synthetic peptide was used as reference substance to search for its natural counterpart in skin secretion of Xenopus. Two peptides were found which were very similar to PYLa except for the absence of the first three amino acids. These 21-amino-acid peptides, termed PGLa, can be generated from PYLa by cleavage after the single arginine residue present in the latter. The two forms of PGLa differ in their retention time on HPLC but have identical amino acid compositions and terminal sequences. Tryptic hydrolysis of synthetic PYLa after the single arginine yields exclusively PGLa with the shorter retention time on HPLC. The chemical difference between the two forms of PGLa is currently not known. The possible biological role of these newly discovered constituents of frog skin secretion is discussed.

Amino Acids↗
PubMed1985

Biosynthesis of peptides in the skin of Xenopus laevis: isolation of novel peptides predicted from the sequence of cloned cDNAs.

From skin of Xenopus laevis, a few peptides have been isolated which are identical or homologous to gastrointestinal hormones and/or neurotransmitters of mammalian origin. We have studied the biosynthesis of these peptides using recombinant DNA techniques. From cDNA librariers constructed from skin mRNA, clones with inserts coding for the precursors of caerulein, thyrotropin releasing hormone and a new peptide termed PGLa have been isolated and sequenced. In the case of caerulein, a small family of precursors containing one, three or four copies of the end product have been detected. The caerulein sequences are separated by homologous sequences which potentially could give rise to additional constituents of skin secretion. Three such peptides have been detected which are presumably liberated from caerulein precursors by cleavage at single arginine residues.

Amino Acid Sequence↗
PubMed1985

The primary structure of the hemoglobin of the dogfish shark (Squalus acanthias). Antagonistic effects of ATP and urea on oxygen affinity of an elasmobranch hemoglobin.

The amino-acid sequence of the hemoglobin of the Dogfish Shark (Squalus acanthias) is presented. The alpha-chains consist of 141 residues and show a Thr/Ser ambiguity at position 3. The beta-chains consist of 142 residues and evidently have no D-helix; they show an Asn/Tyr ambiguity at position 104. Both chains have free N-terminal amino acids. The phylogenetic distance from the human alpha- and beta-chains is indicated by 49.3% and 56.2% amino-acid exchanges. The primary structure is discussed in relation to the oxygen-binding properties of elasmobranch hemoglobin, particularly as regards the antagonistic effects of urea and ATP, and the effects of proton concentration (the alkaline and acid Bohr effects, and the Root effect).

Adenosine Triphosphate↗
PubMed1984

TSH-response patterns to TRH stimulation may indicate therapeutic mechanisms of antidepressant and neuroleptic drugs.

The study was designed to investigate, by weekly thyrotropin-releasing hormone tests, possible patterns of thyroid-stimulating hormone (TSH) responses which may indicate therapeutic mechanisms of antidepressant and neuroleptic drugs in patients with depressive and paranoid-hallucinatory syndrome during their process of recovery (3-9 weeks). 65 depressed women and 33 paranoid-hallucinatory women have been studied while on antidepressant (clomipramine) or neuroleptic (haloperidol) treatment, respectively. Four patterns of TSH response were observed. Patients with a pattern of a 'disblunting TSH response' (normalization of an abnormal low response) during drug treatment had a significantly higher chance to recover compared to patients with other TSH response patterns. This finding was independent of psychopathological features and drugs used for treatment. A hypothesis of 'malactivation' as a pathogenetic indicator of various psychotic states is being presented.

Adult↗
PubMed1984

Hemoglobin D "Los Angeles" in an Austrian family: biochemical identification, clinical aspects, and kindred study.

During a screening program for gestational diabetes, hemoglobin D "Los Angeles" (beta 121 Glu----Gln) was detected by HPLC in an overweight but healthy pregnant Austrian woman. The chromatogram of the hemolysate revealed an unusual splitting of the hemoglobin A1 peak. Sequential analysis of the abnormal peptide indicated hemoglobin D "Los Angeles" heterozygosity in the patient. This is the first description of this variant in Germanic-appearing people. In a kindred study of 49 of the 57 living family members spanning four generations, 22 were heterozygous for hemoglobin D "Los Angeles". How this gene got to this region of Austria is unknown, but transfer via Iran and Turkey seems likely.

Austria↗
PubMed1983

[Initial description of hemoglobin D Punjab in an Austrian family].

Haemoglobin D Punjab was detected in a slightly overweight, but otherwise healthy pregnant woman when she was tested for gestational diabetes within the framework of a screening programme. Chromatographic evaluation of the haemolysate by high-pressure liquid chromatography (HPLC) revealed an unusual "splitting" of the A1 peak into two minor peaks. A diabetes-independent haemoglobin variant was suspected and further investigations, including electrophoresis, purification and sequential analysis of the tryptic peptide, identified the abnormal haemoglobin as haemoglobin D Punjab (beta 121 Glu-Gln). This is the first report of this haemoglobin variant in Austria. Various possible modes of geographical spreading of the gene from Punjab (India) are discussed, the land-route via Turkey being the most favourable hypothesis in this case. An investigation of 6 out of 7 living members of the family was undertaken. In 3 instances haemoglobin D Punjab was confirmed by HPLC and electrophoresis. The investigation of the family is currently being expanded to include a total of five generations.

Adult↗
PubMed1983

[Identification of hemoglobin D Punjab (beta 121 glu replaced by gln) in an Austrian family. Sequence analysis of the abnormal tryptic peptide beta XTp13].

In the course of a screening programme for gestational diabetes an abnormal haemoglobin fraction was detected by high-performance liquid chromatography (HPLC), used for Hb A1c-quantification. Cellulose acetate electrophoresis revealed a heterozygote haemoglobinopathy with approximately equal amounts of Hb A1 and of an abnormal haemoglobin which migrated in the position of Hb S under the conditions used. Preparative separation of these haemoglobin components was performed by use of a DEAE-cellulose column and standard conditions. alpha- and beta-chains were isolated with CM-sepharose and buffer containing 8M urea. The abnormal component of the aberrant haemoglobin was found to be the beta-chains in reconstitution experiments with globin-chains and haemin. A tryptic hydrolysate of the isolated abnormal beta-chains was analysed by means of HPLC and a C2 reverse phase (RP2). Rechromatography of the abnormal fractions on a C18 reverse phase (ODS) led to a pure preparation of peptide beta XTp13. The amino acid sequence analysis of this peptide showed an exchange of glutamic acid to glutamine in position beta 121 (beta 121 Glu----Gln). By these means evidence was obtained for the existence of a heterozygote Hb D Punjab state in the observed patient.

Adult↗
PubMed1983

The TSH-response to TRH: A possible predictor of outcome to antidepressant and neuroleptic treatment.

This study was designed to investigate the possible common patterns of neuroendocrine mechanisms, which may be involved in the therapeutic effects of antidepressant drugs in depressive and of neuroleptic drugs in schizophrenic patients. Sixty-three depressed women (major depressive disorder) and 21 paranoid-hallucinatory women have been studied while on antidepressant (clomipramine) or neuroleptic (haloperidol) treatment, respectively. The neuroendocrine test (TRH-test) was performed at weekly intervals. The change of TSH-response to TRH during treatment, i.e. the treatment associated normalization of a former blunted TSH-response, can tentatively be regarded as a predictor of outcome for depressive and paranoid-hallucinatory patients to their respective drug treatments. Antidepressant and neuroleptic drugs appear to involve the normalization of the TSH-response in their therapeutic effects in that proportion of patients (40%) which showed a blunted TSH-response at admission.

Adolescent↗
PubMed1983

The analysis of a protein-polymorphism. Evolution of monomeric and homodimeric haemoglobins (erythrocruorins) of Chironomus thummi thummi (Insecta, Diptera).

The evolutionary history of 12 Chironomus thummi thummi (CTT) haemoglobins of known primary structures was reconstructed by the maximum parsimony method. This reconstruction demonstrates that the 12 CTT haemoglobin lineages originated monophyletically from a common ancestor within early Insecta and have the lineage to monomeric blood worm haemoglobin as their closest sister group. It can be further deduced that the earliest ancestral CTT haemoglobins were monomers and that a branch to all extant dimeric CTT haemoglobins emerged later in phylogeny near the base of Chironomidae, but perhaps still before Chironomus itself evolved. This ancient, pre-Chironomus history suggests that among insect taxa, now lacking expressed globins, remnants of globin genes might exist as unexpressed pseudogenes. By the parameter of base replacement frequencies, CTT haemoglobins appear as relatively slow-evolving proteins, showing a preponderance of guanine in equilibrium adenine transitions at the first nucleotide position of the codons but not at the second. The most conservatively-evolving amino acid positions are haem contacts; the next most conservative are in interhelical contacts and interior positions involved in stabilization of tertiary structure. Further elucidation of the phylogenetic origins and adaptive evolution of the multiple haemoglobins found in Chironomus will be possible by the maximum parsimony method once haemoglobins or, in their absence, haemoglobin pseudogenes are sequenced in species throughout Chironomidae and related taxa.

Amino Acid Sequence↗
PubMed1983

[The primary structure of the alpha-amylase inhibitor Hoe 467A from Streptomyces tendae 4158. A new class of inhibitors].

The native or modified alpha-amylase inhibitor Hoe 467A - isolated from the culture medium of Streptomyces tendae 4158 - and overlapping peptides were degraded by the automatic Edman technique. The oxidized or aminoethylated or oxidized and maleoylated inhibitor was digested with trypsin and the native inhibitor with pepsin. Further digestion with Staphylococcus aureus proteinase was also carried out. After peptic digestion two cystin peptides were isolated, which allowed the establishment of the disulfide bonds. The alpha-amylase inhibitor is a polypeptid consisting of 74 amino-acid residues with a molecular mass of 7958 Da. The inhibitor is composed of all naturally occurring amino acids except methionine and phenylalanine and shows no sequence homology to known inhibitors. The clinical and pharmacological importance in respect to the inhibitors ability for inactivation of human salivary and pancreatic alpha-amylase is discussed. Especially the proteinase resistance of the inhibitor enables a clinical application in human (e.g. Diabetes mellitus) per os.

Amino Acid Sequence↗
PubMed1981

Effects of antidepressant treatment with clomipramine on hormonal responses to thyrotropin-releasing hormone and insulin-induced hypoglycemia: implications for the "monoamine-hypothesis".

Neuroendocrine test were carried out to study effects of clomipramine treatment in 24 unipolar depressed women. Clomipramine (50-150 mg/day) increased the response of prolactin and thyrotropin to stimulation by thyrotropin-releasing hormone (TRH), while no response of growth hormone (HGH) to TRH was seen. Clomipramine decreased the response of HGH to insulin, while the responses of prolactin and cortisol to insulin were not affected. The findings suggest that the neuroendocrine and antidepressant effects of clomipramine cannot be accounted for entirely on the basis of monoaminergic mechanisms.

Biogenic Amines↗
PubMed1981

Hemoglobins, XXXVIII. Amino acid sequence of a dimeric hemoglobin (erythrocruorin), component VI from Chironomus thummi thummi (CTT VI).

The dimeric hemoglobin CTT VI (Erythrocruorin) was isolated from the hemolymph of the larvae of Chironomus thummi thummi. The globin from CTT VI was subjected to trypsin, limited trypsin and cyanogen bromide digestion. For elucidation of the sequence in the C-terminal region, cleavage with Staphylococcus aureus V8 protease was also carried out. The peptides were separated by gel and ion-exchange chromatography. The handling of some large fragments was facilitated by maleylation and subsequent ion-exchange chromatography with conservation of the maleyl groups. The amino acid sequence was determined by automatic Edman degradation. The order of the peptides was provided by overlaps, but in two cases by homology only (for residues 98 and 99, and 109 and 110). The hemoglobin consists of 2 x 147 amino acids with a molecular weight of 32411. The sequence of CTT VI is compared with a monomeric (CTT III) and a dimeric hemoglobin (CTT II beta) and the human alpha-chains. The structural differences are discussed.

Amino Acid Sequence↗
PubMed1981

[The sequence of the alpha-amylase inhibitor Hoe-467 A (alpha-amylase inactivator Hoe-467 A) from Streptomyces tendae 4158].

An alpha-amylase inhibitor isolated from Streptomyces tendae, strain 4158 was re-purified by chromatography on CM- and DEAE-cellulose column. Two inhibitors could be characterized: alpha-amylase inhibitor Hoe-467 A (with aspartic acid as N-terminal residue), and alpha-amylase inhibitor Hoe-467 S (with serine as N-terminal residue). The primary structure was determined by automatic Edman-degradation procedures of the aziranized inhibitor and tryptic peptides, derived from digestions of the performic oxidized, aziranized and maleylated inhibitor, respectively. The alpha-amylase inhibitor Hoe-467 A consists of 74 residues and has a calculated molecular weight of 7958. It is composed of all common amino acids except methionine and phenylalanine. Digestion with pepsin was carried out to determine the disulfide bonds. Two fractions could be isolated, containing one cystine each giving information about the positions of the disulfide bridges. The possible clinical application of the inactivator (diabetes mellitus) is pointed out.

Amino Acid Sequence↗
PubMed1981

[Human embryonic haemoglobins. Ac-Ser-Leu-Thr-is the N-terminal sequence of the zeta-chains (author's transl)].

The complete amino acid sequence of the embryonic zeta-chains has been reported in an earlier communication (Aschauer, H., Sanguansermsri, T. & Braunitzer, G. (1981), Hoppe-Seyler's Z. Physiol. Chem. 362, 1159-1162). To elucidate the nature of the N-terminal blocking group, tryptical cleavage of the zeta-chains was carried out and the N-terminal tryptic tetrapeptide was isolated by high performance liquid chromatography on reversed phase (RP 8). The tetrapeptide was digested with pronase and the mixture was subjected to mass spectrometry by chemical ionization. By this method Ac-Ser was found to be the N-terminus. In a second experiment the tetrapeptide was permethylated and analysed by mass spectrometry with electron ionization. The N-terminal sequence was found to be Ac-Ser-Leu-Thr-.

Amino Acid Sequence↗
PubMed1981

[Human embryonic haemoglobins. The primary structure of the zeta chains (author's transl)].

The primary structure of the embryonic zeta-chains of humans is given. Blood was obtained from a case with hydrops foetalis syndrom due to homozygous alpha-thalassemia 1. The zeta-chains were isolated by high performance liquid chromatography on reversed phase (RP8). The peptides for sequence work were generated by chemical methods (cyanogen bromide cleavage and acid cleavage at the Asp-Pro bond) and enzymatic cleavages with trypsin of unmodified and succinylated zeta-chains. The peptides were separated by high performance liquid chromatography and sequenced by automatic N-terminal degradation procedures. The N-terminal residue of the zeta-chains is blocked. Therefore the sequence of the N-terminal tryptic peptide was determined after incubation with chymotrypsin. The zeta-chains are alpha-type chains and consist of 141 amino acid residues. The alignment of the zeta-chains with the human alpha-chains shows 57 amino acid exchanges: Thus it is evident that there is a greater phylogenetic distance between the alpha type chains than between the beta-type chains.

Amino Acid Sequence↗