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R Egger

Publications and source records attributed to R Egger.

At least 37 records · Page 2Linked to original sources
PubMed1995

Long-term treatment with interferon-alpha 2b for severe pruritus in patients with polycythaemia vera.

Pruritus is a major clinical problem in patients with polycythaemia vera (PV). Conventional symptomatic treatment is unsatisfactory. Recently, a favourable effect of interferon-alpha on pruritus in patients with PV has been reported. Also, interferon-alpha suppresses the increased haemopoiesis in PV. However, long-term treatment with interferon-alpha may be hampered by side-effects and the inconvenience of chronic subcutaneous injection therapy. We conducted a long-term study (median follow-up 13 months) of the efficacy and tolerability of interferon-alpha in 15 patients (mean age 68 years) with PV and severe pruritus. Six patients were evaluable after 1 year. Pruritus significantly improved in 12/15 patients. Haematological control improved, as evidenced by a decreased number of phlebotomies from a mean of 4.3 in the year before the study to 1.8 while on interferon-alpha. Leucocyte and platelet numbers also decreased significantly. Five patients (33%) did not tolerate interferon-alpha. The effects of interferon-alpha could not be ascribed to an inhibitive effect on histamine production or to the disappearance of the abnormal erythroid progenitor clone, because erythropoietin-independent erythroid colony formation persisted during interferon-alpha treatment. We conclude that long-term interferon-alpha treatment is feasible and effectively relieves pruritus in patients with PV, but side-effects are an important concern. The optimal dose regimen that is well tolerated, relieves pruritus, and offers satisfactory haematological control at the same time remains to be established.

Aged↗
PubMed1990

Two precursors of thyrotropin-releasing hormone from skin of Xenopus laevis. Each contains seven copies of the end product.

From the skin of Xenopus laevis, the cloned cDNAs of two precursors of thyrotropin-releasing hormone have been isolated and sequenced. These encode almost identical precursor polypeptides each containing seven copies of the end product flanked by typical prohormones processing signals. Northern blot analysis has corroborated the existence of two thyrotropin-releasing hormone precursor mRNAs of similar size as the cloned cDNA and demonstrated the existence of a third smaller species as well. Two or more mRNAs for this precursor are also present in the brain and eyes of X. laevis adults and tadpoles.

Amino Acid Sequence↗
PubMed1990

Molecular cloning of a cDNA encoding the bombesin precursor in skin of Bombina variegata.

A cDNA library was constructed using poly(A)-rich RNA isolated from skin of the frog Bombina variegata. This library was screened with two oligo-nucleotides complementary to parts of the sequence of bombesin. The nucleotide sequence of one of the cloned cDNAs encoding a bombesin precursor is presented. The predicted polypeptide contains a single copy of the end-product. The bombesin sequence is preceded by a leucine residue suggesting an unusual type of precursor processing.

Amino Acid Sequence↗
PubMed1990

cDNAs encoding [D-Ala2]deltorphin precursors from skin of Phyllomedusa bicolor also contain genetic information for three dermorphin-related opioid peptides.

We present the structure of four precursors for [D-Ala2]deltorphins I and II as deduced from cDNAs cloned from skin of the frog Phyllomedusa bicolor. These contain the genetic information for one copy of [D-Ala2]deltorphin II and zero, one, or three copies of [D-Ala2]deltorphin I. In each case, the D-alanine of the end product is encoded by a normal GCG codon for L-alanine. In addition, the existence of three peptides related to dermorphin was predicted from the amino acid sequence of the precursors. These peptides were synthesized with a D-alanine in position 2 and their pharmacological properties were tested. Two of them, [Lys7]dermorphin-OH and [Trp4,Asn7]dermorphin-OH, were found to have roughly the same affinity and selectivity for mu-type opioid receptors as dermorphin.

Amino Acid Sequence↗
PubMed1987

D-alanine in the frog skin peptide dermorphin is derived from L-alanine in the precursor.

A D-alanine-containing peptide termed dermorphin, with potent opiate-like activity, has been isolated from skin of the frog Phyllomedusa sauvagei. Complementary DNA (cDNA) libraries were constructed from frog skin messenger RNA and screened with a mixture of oligonucleotides that contained the codons complementary to five amino acids of dermorphin. Clones were detected with inserts coding for different dermorphin precursors. The predicted amino acid sequences of these precursors contained homologous repeats of 35 amino acids that included one copy of the heptapeptide dermorphin. In these cloned cDNAs, the alanine codon GCG occurred at the position where D-alanine is present in the end product. This suggests the existence of a novel post-translational reaction for the conversion of an L-amino acid to its D-isomer.

Alanine↗
PubMed1986

Sequence of preprocaerulein cDNAs cloned from skin of Xenopus laevis. A small family of precursors containing one, three, or four copies of the final product.

From skin of Xenopus laevis, cDNA libraries were constructed and clones coding for the precursors of caerulein were isolated and sequenced. Using restriction endonuclease digestions, three different types of preprocaerulein cDNAs could be discerned. These were termed types I, III, and IV in accordance with the number of caerulein copies present in the sequence, the type III being the most abundant one. An incomplete copy of a fourth variant, termed type I', was also found. Besides deletions/insertions encompassing one or two caerulein sequences, these types also differ from each other by several point mutations. In the homologous precursor polypeptides deduced from the nucleotide sequence of these cloned cDNAs, the caerulein copies are flanked by complex processing sequences. These are Arg-Arg-Phe-Ala-Asp-Gly or Arg-Arg-Asp-Gly at the amino-terminal side and Gly-Arg-Arg at the carboxyl end. Between caerulein copies, highly homologous segments are present both at the polypeptide and cDNA level. This homology is evident both within a given precursor, where up to three such segments are present, and between the different types of precursors. We conclude that preprocaerulein cDNAs in the skin of X. laevis represent a small family, at least part of which is derived from different genes rather than being formed by alternative splicing of pre-mRNAs.

Amino Acid Sequence↗
PubMed1986

The development of chromosomally coded beta-lactamase production by Escherichia coli after in vitro selection with ampicillin, cefoxitin and ceftriaxone.

Subclones of Escherichia coli K12 921 which produced a chromosomal beta-lactamase were naturally selected in vitro with ampicillin, cefoxitin and ceftriaxone. The selected subclones were identical with respect to beta-lactamase production, resistance spectrum and resistance level, regardless of the selection agent. A ceftriaxone selection following an ampicillin selection led to higher ceftriaxone resistance. The beta-lactamase which was formed hydrolysed ceftriaxone to a measurable extent. After incubation of ceftriaxone with the beta-lactamase, the hydrolysed degradation product was demonstrated by thin-layer chromatography.

Ampicillin↗
PubMed1985

[Selection of R plasmid-carrying E. coli pathogens in a mixed population by subinhibitory antibiotic concentrations].

The effect of subinhibitory concentrations of tetracyclin, chloramphenicol, gentamicin and ampicillin in a mixed culture of E. coli was investigated in a chemostat in order to determine minimal selection concentration of these drugs. The mixed culture consisted of three clones of E. coli K12 921. One of these clones was plasmid free, one harboured the F'lac plasmid and the third one an R-factor. The antibiotics tetracyclin, chloramphenicol and gentamicin selected the antibiotic resistant R-factor bearing strain at a concentration of 1/10 of the minimal inhibition concentration. Subinhibitory concentrations of ampicillin failed to select the R-factor bearing strain because this strain produced a secreted betalactamase.

Ampicillin↗
PubMed1984

Biosynthesis of thyrotropin releasing hormone in the skin of Xenopus laevis: partial sequence of the precursor deduced from cloned cDNA.

Skin of Xenopus laevis contains relatively large quantities of thyrotropin releasing hormone (TRH). Total mRNA isolated from skin was cloned in the plasmid pUC8. Among 1400 cDNA clones, one was found with an insert of 478 nucleotides coding for the amino-terminal part of prepro-TRH. This clone was detected using a mixture of two synthetic undecanucleotides for colony hybridization. The single open reading frame starts with a methionine residue and a stretch of hydrophobic amino acids, as is typical for signal peptides, and terminates at the poly(C) tail without a stop codon. The deduced polypeptide of 123 amino acids contains three copies of the sequences Lys-Arg-Gln-His-Pro-Gly-Lys Arg-Arg and a fourth incomplete copy at the carboxyl end. Typical pro-hormone processing at this sequence would yield pGlu-His-Pro.NH2,i.e. TRH. It is concluded that the cloned part of the mRNA codes for prepro-TRH and that the TRH precursor from skin of X. laevis is a polyprotein containing at least four copies of the end product in its amino acid sequence.

Amino Acid Sequence↗
PubMed1983

R-selection of subbacteriostatic tetracyclin-concentrations.

We investigated the smallest R-factor selecting tetracyclin concentration in a chemostat. All experiments were performed with a miscellaneous culture of three clones of the E. coli K12 921 strain. The first clone was plasmid-free, the second one harboured the R270 (Tc, Su) Inc F II rep and the third one the F'lac-plasmid Inc F I derep. The influence of different tetracyclin concentrations on the development of the viable count of these three clones was investigated in batch and in steady state culture phase. The steady state was kept for about three hours. It served to enforce the selection effect of the antibiotic. A selection effect was already stated with 0.25 microgram Tc/ml. That is to say with 1/10 of the MIC (2.5 micrograms Tc/ml) of the clones used. The importance of these results will be discussed.

Culture Media↗