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G Riess

Publications and source records attributed to G Riess.

At least 37 records · Page 2Linked to original sources
PubMed1989

Proteolytic enzymes from recombinant Streptomyces lividans TK24.

Different proteases from the culture fluids of recombinant Streptomyces lividans strains were isolated. Several individual proteases were separated and characterized. A chymotrypsin-chylike activity (CLA) was identified that specifically degrades a fusion protein between the alpha-amylase inhibitor from S. tendae (Tendamistat, HOE467) and proinsulin from the monkey Macaca fascicularis. The effective chemical inhibition of the degrading enzyme is demonstrated.

Amino Acid Sequence↗
PubMed1989

Heterologous expression of the alpha-amylase inhibitor gene cloned from an amplified genomic sequence of Streptomyces tendae.

The coding region for a secreted proteinaceous inhibitor of the human alpha-amylase (tendamistat; HOE 467) was identified by using a synthetic oligonucleotide probe. The gene is part of a 37-kilobase amplified genomic sequence found in an overproducing mutant of Streptomyces tendae. After subcloning, sequence analysis revealed an open reading frame of 312 base pairs preceded by a putative ribosome-binding site. The reading frame is 30 codons longer than necessary for the mature protein. This sequence coded for an amino-terminal extension of tendamistat and shows typical features of a signal peptide. After being cloned into Streptomyces vector plasmids and transformed to the heterologous host, Streptomyces lividans TK24, the gene was expressed, and the alpha-amylase inhibitor was correctly processed and secreted into the culture medium. The amount of secreted protein was dependent on the gene dosage and on the promoter arrangement.

Amino Acid Sequence↗
PubMed1986

[TCP magnet system].

Explore the source record for details and available documents.

Dental Implantation, Endosseous↗
PubMed1984

Apparent superiority of H2-receptor stimulation and simultaneous beta-blockade over conventional treatment with beta-sympathomimetic drugs in post-acute myocardial infarction: cardiac effects of impromidine--a new specific H2-receptor agonist-in the surviving catecholamine-insensitive myocardium.

Left ventricular infarction (AMI) was produced in experimental animals and the contractile response to beta-adrenergic and H2-histaminergic stimulation by isoproterenol and impromidine tested in the isolated perfused heart preparation. Adenylate cyclase activity as well as binding characteristics of [3H]-dihydroalprenolol ([3H]-DHA), [3H]-methyl-tiotidine ([3H]-TIOT) and [3H]-quinuclidinyl benzilate ([3H]-QNB) to cardiac beta 1-, H2- and cholinergic muscarinic receptors were determined in sarcolemmal membrane preparations of the right ventricle of the same hearts. In addition, an attempt was made to elucidate the therapeutic value of post-AMI treatment with impromidine in the presence and absence of beta-blockade, in contrast to administration of prenalterol and the conventional therapy with beta-sympathomimetic drugs, e.g. dobutamine. Three days post-AMI the dose-response curve for isoproterenol of right ventricular dP/dtmax was significantly depressed, while the inotropic effect of impromidine was not impaired. Stimulation of adenylate cyclase activity by isoproterenol was reduced by 80% whereas impromidine and NaF stimulation rates were unaltered. Receptor-binding studies indicated a 90% loss and 10-times lowered affinity (KD) of the remaining beta-receptors while specific [3H]-TIOT- and [3H]-QNB-binding was unchanged. Administration of dobutamine increased mortality rates and extension of infarct size, led to a further decrease in contractile response to isoproterenol, induced complete insensitivity of adenylate cyclase to isoproterenol stimulation and caused pronounced additional reduction of number and affinity of [3H]-DHA-binding sites. In contrast, all above alterations were prevented by treatment with either prenalterol or combined administration of impromidine plus metoprolol. It is concluded, that these alterations in the non-ischemic, uninvolved myocardium post-AMI are the result of catecholamine-induced specific damage of sarcolemmal beta-receptors. Furthermore, treatment with H2-agonists in combination with beta-blocking agents may have beneficial effects, whereas conventional therapy with beta-sympathomimetic drugs tends to worsen the already depressed function of the beta-adrenergic stimulation mechanism.

Adenylyl Cyclases↗
PubMed1983

Spontaneous deletions of the chromosome-mobilizing plasmid R68.45 in Pseudomonas aeruginosa PAO.

In Pseudomonas aeruginosa strain PAO the chromosome-mobilizing IncP-1 plasmid R68.45 was unstable whereas the parent plasmid R68 was stable. The instability of R68.45 was observed in rec+ and rec strains within about 100 generations after conjugal transfer of the plasmid and, to a lesser extent, in established R68.45 donor strains. Two phenotypically distinct classes of R68.45 derivatives were obtained: (i) CbR (carbenicillin-resistant), TcR (tetracycline-resistant), KmR (kanamycin-resistant), Tra+ (transfer proficient), Cma- (chromosome-mobilizing ability), lacking the duplicated IS21 copy typical of R68.45 and indistinguishable from R68 by restriction enzyme analysis; (ii) CbR TcR KmS Tra- Cma-, due to deletion of one IS21 copy, the adjacent KmR gene, and a variable part of the Tra-1 region including, in most cases, the origin of transfer (oriT). Both types of deletion derivatives were stable. R68.45 derivatives lacking the Tra-2 region were not recovered spontaneously, but could be constructed in vitro and were stable in strain PAO. Deletion formation of type ii as well as Cma did not depend on homologous recombination and can be ascribed to functions of the duplicated IS21. Chromosome mobilization does not appear to require obligatory transfer of the entire R68.45 plasmid. Four ClaI restriction sites were mapped on R68 extracted from P. aeruginosa. One of these sites was cryptic, presumably because of methylation, when the plasmid was prepared from Escherichia coli (dam+).

Chromosome Deletion↗
PubMed1983

Analysis of IS21-mediated mobilization of plasmid pACYC184 by R68.45 in Escherichia coli.

Escherichia coli plasmids like pACYC184 or pBR325 can be mobilized by the P-type plasmid R68.45, which carries a tandem duplication of insertion element IS21, at a frequency of 10(-3)-10(-5) per donor cell. Analysis of exconjugant cells revealed that plasmid mobilization occurs via cointegrate formation involving transposition of IS21. No resolution of cointegrates of pACYC184 and the P-type plasmid could be found in recA recipient cells. In the cointegrate, the E. coli plasmid is flanked by single copies of IS21 in direct orientation. After resolution of the cointegrate in recA+ recipients, the mobilizing plasmid R68.45 lost one copy of IS21 becoming indistinguishable from plasmid R68. It was shown that during mobilization, insertion element IS21 transposes to the mobilized plasmid. Insertion sites and orientations of IS21 in 33 pACYC184::IS21 insertion mutants have been determined: IS21 was found to be integrated in plasmid pACYC184 in different regions but only in one orientation. The IS21 tandem structure of plasmid R68.45 and its role in the mobilization process is discussed.

Chromosome Mapping↗
PubMed1982

Deleterious effects of cimetidine in the presence of histamine on coronary circulation. Possible clinical implications in anaphylactic states in individuals with coronary heart disease.

The present study characterizes effects of histamine in the presence of the H2-antagonist cimetidine on the coronary circulation of the isolated perfused spontaneously beating guinea pig heart. Infusion of histamine (2 x 10(-8) mol/1-5 x 10(-6) mol/l) induced a dose-dependent coronary dilation, comparable to the effect of isoproterenol and two highly-selective H2-agonistic compounds, impromidine and dimaprit. In the presence of cimetidine (5 x 10(-6) mol/l), however, coronary response to histamine was reversed in a manner that a dose-dependent coronary constriction occurred with coronary spasm and a flow rate approaching zero at histamine concentrations above 8 x 10(-7) mol/l, whereas the dilatory effect of impromidine and dimaprit was completely antagonized. In contrast, the histamine-induced constriction in the presence of cimetidine could be nearly abolished by additional infusion of the H1-antagonistic compound mepyramine (5 x 10(-5) mol/l). Is is concluded that H1- and H2-receptors are present in the coronary smooth muscle, H1-receptors mediating constriction and H2-receptors mediating coronary dilation. Speculation is provided that histamine may have hazardous effects in anaphylactic states if cimetidine is administered simultaneously, e.g., to prevent or cure peptic ulcer. Other possible clinical implications will be discussed.

Anaphylaxis↗
PubMed1981

Cardiac contractile and metabolic effects mediated via the myocardial H2-receptor adenylate cyclase system. Characterization of two new specific H2-receptor agonists, impromidine and dimaprit, in the guinea pig and human myocardium.

The present study chartacterizes myocardial effects of two new histaminergic H2-receptor specific compounds, impromidine, and dimaprit, on cardiac contractile and metabolic parameters of the guinea pig heart and human papillary muscle in comparison to the well-known effects of catecholamines. Impromidine and dimaprit produced a dose-dependent stimulation of the right and left ventricular contractile force in the isolated perfused biventricular catheterized guinea pig heart with maximal stimulation rates equal to those of isoproterenol. Hemodynamic equieffective doses of isoproterenol (2.8X10(-9) mol/l), histamine (1.1X10(-5) mol/l), impromidine (4.6X10(-7) mol/l, and dimaprit (8.5X10(-6) mol/l) induced nearly identical increases in tissue concentrations of c-AMP. All compounds dose-dependently enhanced the activity of the myocardial adenylate cyclase with very similar KA-values in a particulate sarcolemmal membrane preparation of both guinea pig ventricles and human papillary muscles. No effect of either compound was seen on cardiac phosphodiesterase activity. Selective administration of the beta1-blocking agent metoprolol and the H2-receptor antagonist cimetidine clearly discriminates two independent receptors linked to the sarcolemmal adenylate cyclase system in the guinea pig and human myocardium. This is further supported by results obtained from beta-receptor-binding studies in which an interference of impromidine and dimaprit with the stereospecific binding of (-)[3H]-dihydroalprenolol to cardiac beta-receptors could be definitely excluded. The possible therapeutic role of both H2-agonists on the non-ischemic, surviving myocardium, which is transiently refractory to beta-adrenergic stimulation by catecholamines after myocardial infarction, will be discussed.

Adenylyl Cyclases↗
PubMed1981

Impaired beta-adrenergic stimulation in the uninvolved ventricle post-acute myocardial infarction: reversible defect due to excessive circulating catecholamine-induced decline in number and affinity of beta-receptors.

Left ventricular infarction (AMI) was produced in experimental animals and the contractile response to isoproterenol was tested in the isolated perfused heart preparation. Adenylate cyclase activity, phosphodiesterase activity, and beta-receptor binding characteristics were determined in a sarcolemmal preparation of the right ventricle of the same hearts. Three days post-AMI the dose-response curve for isoproterenol of right ventricular dP/dtmax was significantly depressed, while the inotropic effect of histamine was not impaired. Stimulation of adenylate cyclase activity by isoproterenol was reduced by 70% in the membrane preparation, whereas histamine and NaF stimulation rates were unaltered; phosphodiesterase activity was unchanged. In contrast, beta-receptor binding studies with [3H]-DHA1 indicated 74% loss and 10 times lowered affinity (KD) of the remaining beta-receptors, while specific [3H]-QNB1 binding was unchanged. All of the above alterations were prevented by pretreatment with reserpine or metoprolol. It is concluded that these abnormalities in the nonischemic surviving myocardium post-AMI are the result of specific reversible damage of sarcolemmal beta-receptors due to excessive levels of circulating catecholamines.

Adenylyl Cyclases↗
PubMed1980

A new implant philosophy.

This form of tooth implant appears to exhibit great potential since it eliminates the disorganized connective tissue layer present at the implant/bone interface of most other devices. Also, as established for other implants, as long as a tight cuff of relatively immovable tissue exists around the polished cervical collar of an implant, an effective seal against the ingress of oral fluid and toxic irritants appears to be maintained, although the nature of this seal has yet to be determined. In addition, the epimobile superstructure serves to dissipate occlusal stress on the "ankylosed" implant. The prognosis of an implant is determined in part by its associated superstructure. There is a need for research into the loading that can be accommodated by an implant. Further study is required to ascertain the full potential of this implant system.

Aluminum Oxide↗
PubMed1980

[Principles of the TCP-implantation system after 2 years of clinical experience].

The TCP implantation system is based on absorbable tricalcium phosphate ceramics which is used in different ways as porcelain-fused-to-metal material. The strict and complex application of preimplantologic and peri-implantologic principles, particularly the cleansing and preparation of the implant bed and of the bone tissue, as well as newly developed, internally cooled cutting and self-cleaning instructions are of special importance. The shape of the implant and the operative technique also play an important role in achieving a successful oral implant. The nonmetalic surface of the TCP implant has proved to be an important advantage. Since these implants induce a fusion with the bone tissue which does not include connective tissue, the use of elastic coupling elements that functionally imitate the periodontal tissue have proved to be an important factor in the primary and long-term success of the implant. The gnathologic formation of the chewing surfaces is just as important as the need for proper information, training, and supervision of the dentists as well as control of implants.

Blade Implantation↗
PubMed1979

Relationship of group P1 plasmids revealed by heteroduplex experiments: RP1, RP4, R68 and RK2 are identical.

The molecular relationships of the IncP1 plasmids RP1, RP4, R68 and RK2 were tested by electron microscopic examination of heteroduplexes. In several hybridization experiments molecules were detected which had a 7.8% portion of incomplete reannealing. This 'heterologous region' could be explained by the typical renaturation behaviour of the transposon Tn1. The identity of the Tn1 transposon present in RP1 and RP4 was proved by heteroduplex experiments with lambda phage DNA containing this transposon. These results indicated that the plasmids RP1 and RP4 are identical. Additional heteroduplex experiments between plasmids R68.45 and RP8 and between R68.45 and RK2 were performed. R68.45, a derivative of R68, has a small DNA insertion and RP8 can be regarded as a large insertion mutant of RP4; both insertions were used as single-stranded hybridization markers. From the hybrid molecules formed, it was deduced that R68 and RK2 are identical with RP1 and RP4 as far as molecular structure is revealed by the technique used.

Ampicillin↗