Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.24.55 (PTR)
 433 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have generated a panel of 55 somatic cell hybrids retaining fragments of human chromosome 4. Each hybrid has been characterized cytogenetically by FISH and molecularly by 37 STSs, evenly spaced along the chromosome. The panel can be exploited to map subregionally DNA sequences on chromosome 4 and to generate partial chromosome paints useful in the characterization of chromosomal rearrangements involving this chromosome. Furthermore, a panel of 84 YACs mapping on chromosome 4 has been characterized by FISH. A subset of this panel is recognized by STSs used in the somatic cell hybrid characterization. In this way a correlation between the genetic and the physical maps can be established. These resources have been used to investigate the conservation of the phylogenetic chromosome IV in great apes. The results indicate that all the pericentric inversions that differentiate chromosome IV in these species are distinct and that one of the breakpoints frequently lies very close to the centromere. In 4 instances, the YAC containing the breakpoint was identified. The breakpoint in IVq of PTR and MMU lies in the same YAC, suggesting that this breakpoint has been utilized twice in the evolutionary history of this chromosome.
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PMID:Molecular cytogenetic resources for chromosome 4 and comparative analysis of phylogenetic chromosome IV in great apes. 1070 78

Karyotypic homologies in relation to human chromosome 14 and 9 were studied through comparative mapping of the immunoglobulin C epsilon genes in higher primates by fluorescence in situ hybridization (FISH) technique. The C epsilon genes will be suitable probes for the analysis of evolutionary rearrangements due to that the multiple recombinational events such as gene duplications and deletions have occurred repeatedly in the immunoglobulin CH gene family (IGH@) during the course of primate evolution. IGH@ locating on the terminal region of human chromosome 14 (HSA14), at band HSA14q32.33, has generated multiple pseudogenes and among subclasses of IGH@ the C epsilon genes have shown most dynamic changes with generating both truncated type (C epsilon 2) and processed type (C epsilon 3) pseudogenes. In this study, chromosomal homologies and rearrangements on HSA14 (C epsilon 1) and HSA9 (C epsilon 3) in relation to the evolutionary genesis of their primate homologous chromosomes in speciation were investigated by comparative mapping with FISH and chromosome painting (ZOO-FISH) techniques. Comparative mapping of the C epsilon 1 gene at HSA14q32.33 was carried out in seven species of nonhuman primates: common chimpanzee (PTR), pygmy chimpanzee (PPA), gorilla (GGO), orangutan (PPY), white-handed gibbon (HLA), agile gibbon (HAG), and Japanese macaque (MFU). The C epsilon 1 gene was assigned to the telomeric region of HSA14 homologues in each species, namely, PTR15q32, PPA15q32, GGO18q16, PPY15q32, HLA17qter, HAG17qter, and MFU7q29, respectively. These results suggested that HSA14 has high degree of syntenic organization with its primate homologues confirmed by ZOO-FISH. Concerning HSA9, comparative mapping of the C epsilon 3 gene at HSA9p24.2-->p24.1 was performed. The mapped positions indicated the HSA9 homologous regions detected by ZOO-FISH in each species, namely, PTR11q34, PPA11q34, GGO13q22, PPY13q16, HLA8qter, HAG8qter, and MFU14q22, respectively, suggesting that several dynamic chromosomal rearrangements including at least twice pericentric inversions have occurred during the course of hominoid evolution. The comparison of syntenic groups and painting results has provided a hypothesis of the evolutionary genesis of HSA9 and its homologues with defined breakpoints on the present chromosomes. Likewise, studies on karyotype evolution will be promoted by combining comparative mapping with ZOO-FISH that can more clearly define the chromosomal rearrangements among species.
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PMID:Studies on karyotype evolution in higher primates in relation to human chromosome 14 and 9 by comparative mapping of immunoglobulin C epsilon genes with fluorescence in situ hybridization. 1085 38

We examined the effects of the alpha(2)-adrenoceptor (alpha(2)-AR) agonist clonidine on pressure-flow relationships in the upper airway. Inspired and expired airflows, subglottic tracheal pressure (PTR), mask pressure and middle pharyngeal constrictor (MPC) and diaphragm electromyogram (EMG) activities were recorded in awake standing goats. Clonidine-induced central apneas were always associated with continuous tonic activation of the MPC. Subglottic PTR during expiration increased progressively in a dose-dependent manner after clonidine administration. In all cases, positive subglottic PTR was maintained throughout the duration of clonidine-induced apneas and was sufficient to retard or prevent expiratory flow during early and mid-expiration indicating complete airway closure. The effects of clonidine were reversed by selective alpha(2)-AR blockade with SKF-86466. Central apneas after spontaneous augmented breaths (sighs) were associated with continuous tonic activation of the MPC throughout the duration of the prolonged TE intervals. However, subglottic PTR during expiration was not significantly different from control breaths and there was no evidence of increased expiratory airway resistance or delayed expiratory flow. We conclude that continuous tonic activation of pharyngeal adductor muscles appears to be a constant feature of central apnea in the awake goat independent of the initiating cause of the apnea. However, our data suggest that MPC activation alone may not be sufficient to cause complete closure of the upper airway during central apnea.
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PMID:Clonidine induces upper airway closure in awake goats. 1100 84

The original article to which this Erratum refers was published in Phytotherapy Research 14(5) 2000, 344-346. Following the publication of this paper in the August 2000 issue of Phytotherapy Research (14(5):344-346), it has come to our attention that there is a misleading statement regarding conclusions cited from the work of Butterweck et al. 1998. The discussion in the recent PTR paper states that those authors are 'in favour of the hypothesis that the antidepressant activity is due to the hypericin only'. We wish to make it clear that this is not the case, and the Butterweck paper actually concludes that 'both naphthodianthrones must be considered as active constituents of the crude extract of H. perforatum. However, previous studies indicate that the other consitutuents of the crude drug also have activity'. The authors apologize for this error and are happy to correct it.
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PMID:R. Daudt, G. L. Von poser, G. Neves and S. M. K. Rates, 'Screening for the antidepressant activity of some species of hypericum from south Brazil'. Phytotherapy research14(5) 2000, 344-346 1111 12

Somatostatin, also known as somatotropin release-inhibiting factor (SRIF), is a natural cyclic peptide inhibitor of pituitary, pancreatic, and gastrointestinal secretion. Its long-acting analogs are in clinical use for treatment of various endocrine syndromes and gastrointestinal anomalies. These analogs are more potent inhibitors of the endocrine release of GH, glucagon, and insulin than the native SRIF; hence, they do not display considerable physiological selectivity. Our goal was to design effective and physiologically selective SRIF analogs with potential therapeutic value. We employed an integrated approach consisting of screening of backbone cyclic peptide libraries constructed on the basis of molecular modeling of known SRIF agonists and of high throughput receptor binding assays with each of the five cloned human SRIF receptors (hsst1-5). By using this approach, we identified a novel, high affinity, enzymatically stable, and long-acting SRIF analog, PTR-3173, which binds with nanomolar affinity to human SRIF receptors hsst2, hsst4, and hsst5. The hsst5 and the rat sst5 (rsst5) forms have the same nanomolar affinity for this analog. In the human carcinoid-derived cell line BON-1, PTR-3173 inhibits forskolin-stimulated cAMP accumulation as efficiently as the drug octreotide, indicating its agonistic effect in this human cell system. In hormone secretion studies with rats, we found that PTR-3173 is 1000-fold and more than 10,000-fold more potent in inhibiting GH release than glucagon and insulin release, respectively. These results suggest that PTR-3173 is the first highly selective somatostatinergic analog for the in vivo inhibition of GH secretion, with minimal or no effect on glucagon and insulin release, respectively.
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PMID:Novel long-acting somatostatin analog with endocrine selectivity: potent suppression of growth hormone but not of insulin. 1114 12

The model eukaryote Saccharomyces cerevisiae has two distinct peptide transport mechanisms, one for di-/tripeptides (the PTR system) and another for tetra-/pentapeptides (the OPT system). The PTR system consists of three genes, PTR1, PTR2 and PTR3. The transporter (Ptr2p), encoded by the gene PTR2, is a 12 transmembrane domain (TMD) integral membrane protein that translocates di-/tripeptides. Homologues to Ptr2p have been identified in virtually all organisms examined to date and comprise the PTR family of transport proteins. In S. cerevisiae, the expression of PTR2 is highly regulated at the cellular level by complex interactions of many genes, including PTR1, PTR3, CUP9 and SSY1. Oligopeptides, consisting of four to five amino acids, are transported by the 12-14 TMD integral membrane protein Opt1p. Unlike Ptr2p, distribution of this protein appears limited to fungi and plants, and there appears to be three paralogues in S. cerevisiae. This transporter has an affinity for enkephalin, an endogenous mammalian pentapeptide, as well as for glutathione. Although it is known that OPT1 is normally expressed only during sporulation, to date little is known about the genes and proteins involved in the regulation of OPT1 expression.
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PMID:Multiplicity and regulation of genes encoding peptide transporters in Saccharomyces cerevisiae. 1139 5

A backbone bridged and disulfide bridged bicyclic somatostatin analogue, compound 1 (PTR-3205), was designed and synthesized by solid-phase methodology. The binding of compound 1 to the five different somatostatin receptors, expressed in CHO or COS-7 cells, indicate a high degree of selectivity towards hsstr2. The three-dimensional structure of this compound has been determined in DMSO-d(6) and in water by 1H NMR and by molecular dynamics simulations. Similar backbone conformations were observed in both solvents. We have established direct evidence that the backbone of this bicyclic somatostatin analogue assumes a 'folded' conformation in solution, where the lactam ring extends roughly in the plane of the beta-turn. The pharmacophoric region Phe-(D)-Trp-Lys-Thr of compound 1 is in accord with that of both the Veber compound L-363,301 (Merck) and sandostatin. We believe that the enhanced selectivity towards the hsst2 receptor, in comparison with other analogues, is due to its large hydrophobic region, composed of the lactam ring and the Phe side chains at positions 1 and 8.
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PMID:A bicyclic and hsst2 selective somatostatin analogue: design, synthesis, conformational analysis and binding. 1171 1

Bone metastases are one of the most common events in patients with prostate carcinoma. PTH-rP, a protein produced by prostate carcinoma and other epithelial cancers, is a key agent for the development of bone metastases. A PTH-rP-derived peptide, designated PTR-4 was identified, which is capable to bind HLA-A2.1 molecules and to generate PTH-rP-specific cytotoxic T cell (CTL) lines from healthy HLA-A2.1(+) individual peripheral-blood-mononuclear-cells (PBMC). In this model, we investigated the in vitro possibility of generating an efficient PTH-rP specific CTL response by cyclical stimulations with IL-2 and PTR-4 peptide-pulsed autologous dendritic cells (DC), of HLA-A2.1(+) tumour infiltrating lymphocytes (TIL) derived from a patient with metastatic prostate carcinoma. A T cell line generated in this way (called TM-PTR-4) had a CD3(+), CD5(+), CD4(-), CD8(+), CD45(Ro+), CD56(-) immunophenotype and a HLA-A2.1 restricted cytotoxic activity to PTR-4-peptide pulsed CIR-A2 (HLA-A2.1(+)) target cells, PTH-rP(+)/HLA-A2.1(+) CIR-A2 transfected with PTH-rP gene, prostate carcinoma LNCaP cells, and autologous metastatic prostate cancer cells (M-CaP). These lymphocytes were not cytotoxic to HLA-A2.1(+) targets not producing PTH-rP, such as peptide-unpulsed CIR-A2 and colon carcinoma SW-1463, cell lines. Our results provide evidence that PTR-4 peptide-pulsed autologous DC may break the tolerance of human TIL against the autologous tumour by inducing a PTH-rP-specific CTL immune reaction. In conclusion PTR-4 peptide-pulsed autologous DC may be a promising approach for vaccine-therapy and antigen-specific CTL adoptive immunotherapy of hormone-resistant prostrate cancer.
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PMID:A parathyroid-hormone-related-protein (PTH-rP)-specific cytotoxic T cell response induced by in vitro stimulation of tumour-infiltrating lymphocytes derived from prostate cancer metastases, with epitope peptide-loaded autologous dendritic cells and low-dose IL-2. 1174 94

Somatostatin-14 (somatostatin) and its clinically available analogues octreotide, lanreotide, and vapreotide are potent inhibitors of growth hormone, insulin, and glucagon release. Recently, a novel backbone cyclic somatostatin analogue c(GABA-Phe-Trp-(D)Trp-Lys-Thr-Phe-GlyC3-NH(2)) (analogue 1, PTR 3173) that possesses in vivo endocrine selectivity was described. This long-acting octapeptide exhibits high affinity to human recombinant somatostatin receptors (hsst) hsst2, hsst4, and hsst5. Its novel binding profile resulted in potent in vivo inhibition of growth hormone but not of insulin release. We report the synthesis, bioactivity, and structure-activity relationship studies of compounds related to 1. In these analogues, the lactam bridge of 1 was replaced by a backbone disulfide bridge. We present a novel approach for conformational constraint of peptides by utilizing sulfur-containing building units for on-resin backbone cyclization. These disulfide backbone cyclic analogues of 1 showed significant metabolic stability as tested in various enzyme mixtures. Receptor binding assays revealed different receptor selectivity profiles for these analogues in comparison to their prototype. It was found that analogues of 1, bearing a disulfide bridge, had increased selectivity to hsst2 and hsst5; however, they exhibited weaker affinity to hsst4 as compared to 1. These studies imply that ring chemistry, ring size, and ring position of the peptide template may affect the receptor binding selectivity.
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PMID:Human somatostatin receptor specificity of backbone-cyclic analogues containing novel sulfur building units. 1193 20

Data illustrating the performance characteristics of a proton transfer reaction-mass spectrometer (PTR-MS) under both laboratory and field conditions are presented. Under laboratory conditions, we demonstrate that PTR-MS measures (within 10%) a 2.6 ppbv concentration of gaseous dimethyl sulfide. Using a stepwise dilution of a gaseous isoprene standard, we demonstrate the linearity of the response of PTR-MS across 3 orders of magnitude of mixing ratios, from 100 ppbv to less than 100 pptv. By combining this data set with that of its monosubstituted 13C isotopic analogue, we demonstrate the ability of the instrumentto reliably measure concentrations as low as approximately 50 pptv and to detect concentrations at significantly lower levels. We conclude our laboratory characterization by investigating the components of the instrument noise signal (drift, mean, and range) and develop an expression (noise statistic) that reliably predicts the instrumental noise associated with any signal across a wide range of masses. In the field, we deployed a PTR-MS at a clean-air coastal site and an urban kerbside monitoring station to demonstrate the measurement of atmospheric dimethyl sulfide and benzene concentrations, respectively. At both sites, we were able to monitor diurnal variations in concentrations at unprecedented temporal resolutions (<5 min between successive measurements). We then demonstrate how the noise statistic can be applied to enable real fluctuations in atmospheric VOC concentrations to be reliably distinguished from instrument noise. We conclude by demonstrating how PTR-MS can be used to measure real-time VOC emission rate changes from vegetation in response to external forcing by examining the effect varying photon-flux density has upon emissions of isoprene from a Sitka spruce tree.
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PMID:Performance characteristics and applications of a proton transfer reaction-mass spectrometer for measuring volatile organic compounds in ambient air. 1199 66


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