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G J Moore

Publications and source records attributed to G J Moore.

At least 55 records · Page 3Linked to original sources
PubMed1996

Functional magnetic resonance imaging of motor activation in the human cervical spinal cord.

Functional magnetic resonance imaging (fMRI) at 1.5 T of a 30-mm segment of the human spinal cord, centered at the seventh cervical cord segment, showed mean blood-oxygenation-dependent contrast changes in image intensity of 4.8% associated with a unilateral hand-closing task in normal human volunteers. The observed locale of activation in the ipsilateral intermediate and ventral gray matter of the cervical cord contains motoneurons, corticospinal axonal terminations from the hand area of the brain motor cortex, and capillaries supplying the spinal neurons. This noninvasive observation of focal activation within the human spinal cord is consistent with neuronal cooperation over more than one cord segment and suggests that fMRI of the human central nervous system may have wider clinical applications outside of the brain.

Adult↗
PubMed1996

Quantitative in vivo 31P magnetic resonance spectroscopy of Alzheimer disease.

The purpose of this study was to determine whether, in Alzheimer disease (AD) patients, abnormalities in energy charge or phospholipid metabolism could be detected during life with quantitative phosphorus magnetic resonance spectroscopy (31P MRS). We performed in vivo 31P MRS in 16 patients with a clinical diagnosis of probable AD with mild to moderate dementia severity (mean Blessed Dementia Score = 17.5, range = 7-37) and in 8 healthy, nondemented, age-matched, control subjects. MR studies were performed on a commercial 1.5 T MR imager using a volume head coil. We acquired brain spectra by sampling a 6-cm-thick axial slice through the cerebrum (a region that includes approximately 900 ml of brain tissue); we measured beta-nucleoside triphosphate (beta-NTP), phosphocreatine (PCr), phosphomonoesters (PME), phosphodiesters (PDE), and inorganic phosphate (Pi) concentrations, then calculated ratios of these resonances. The beta-NTP, PCr, and Pi resonances in AD and control subjects were not significantly different. These data indicate that brain energy stores are not depleted in AD. No significant differences were detected in the absolute measurements of PME and PDE between the AD and control groups. However, among the calculated ratios, an increase in the PME/PDE ratio of approximately 50%, mostly due to a decrease in the PDE signal, was statistically significant (AD PME/PDE mean = 0.35, range 0.13-0.71; normal PME/PDE mean = 0.22, range 0.16-0.34). We speculate that the difference in PDE reflects changes in the biophysical state of membrane phospholipids in AD.

Aged↗
PubMed1996

Quality of life after radiation therapy for base of tongue cancer.

Quality-of-life (QOL) research in patients treated for head and neck cancer is in its infancy. Early research focused on psychosocial issues related to extensive surgical resection and its consequences. Many advances have been made in both radiotherapy and surgical management. Nevertheless, individuals with head and neck cancer are at risk for significant treatment-related morbidity, which can have a substantial impact on the quality of their life. This article provides an overview of the evolution of QOL research in this population, and presents a series of studies using the Performance Status Scale (PSS) to measure functional QOL in patients with base of tongue cancer who are treated with radiation therapy.

Activities of Daily Living↗
PubMed1995

Angiotensinogen-like epitopes are present in the CNS of Aplysia california and co-localize with urotensin I- and urotensin II-like immunoreactivities in the cerebral ganglia.

Immunohistochemistry was used to demonstrate urotensin I (UI), urotensin II (UII), and angiotensinogen (Ao)-like immunoreactivities (ir) in the CNS of Aplysia californica. The fish UI is a 41 amino acid peptide that has 50% identity with mammalian corticotropin-releasing factor (CRF). Identity also exists between UI and angiotensinogen in a tetrapeptide at the N-terminus. Ao-ir neurones were found in the F cluster of the Aplysia cerebral ganglia. Beaded Ao-ir fibres were seen in the neuropile and commissure of the cerebral, pleural and pedal ganglia. Ao neurosecretory material was also seen in the perineural region of the proximal supralabial nerve. Previously we have demonstrated UI and UII immunoreactivities were present in the CNS of Aplysia. A comparison of adjacent sections of the cerebral ganglia immunostained sequentially for UI, UII and Ao revealed that all three immunoreactivities co-existed in the same cells of the F cluster of the cerebral ganglia. Liquid-phase immunoabsorption of the Ao antiserum revealed that porcine or human angiotensinogen but not UI or UII were able to quench Ao immunostaining. Conversely UI and UII staining were quenched by white sucker (Catatomus commersoni) UI and goby (Gillichtys mirabilis) UII, respectively, but they were not modified by angiotensinogen. These results suggest that UI-, UII-, and Ao-like peptides might co-exist as separate entities in the cerebral ganglia of Aplysia californica where they can act in an integrated and/or independent modulatory way.

Angiotensinogen↗
PubMed1994

Novel synthesis of cyclic amide-linked analogues of angiotensins II and III.

Cyclic amide-linked angiotension II (ANGII) analogues have been synthesized by novel strategies, in an attempt to test the ring clustering and the charge relay bioactive conformation recently suggested. These analogues were synthesized by connecting side chain amino and carboxyl groups at positions 1 and 8, 2 and 8, 3 and 8, and 3 and 5, N-terminal amino and C-terminal carboxyl groups at positions 1 and 8, 2 and 8, and 4 and 8, and side chain amino to C-terminal carboxyl group at positions 1 and 8. All these analogues were biologically inactive, except for cyclic [Sar1, Asp3, Lys5]ANGII (analogue 10) which had high contractile activity in the rat uterus assay (30% of ANGII) and [Lys1, Tyr(Me)4, Glu8]ANGII (analogue 7) which had weak antagonist activity (PA2 approximately 6). Precyclic linear peptides synthesized using 2-chlorotrityl chloride resin and N alpha-Fmoc-amino acids with suitable side chain protection were obtained in high yield and purity and were readily cyclized with benzotriazol-1-yloxytris(dimethylamino)-phosphonium hexafluorophosphate as coupling reagent. Molecular modeling suggests that the ring structure of the potent analogue can be accommodated in the charge relay conformation proposed for ANGII.

Amino Acid Sequence↗
PubMed1994

Role of the NH2-terminal domain of angiotensin II (ANG II) and [Sar1]angiotensin II on conformation and activity. NMR evidence for aromatic ring clustering and peptide backbone folding compared with [des-1,2,3]angiotensin II.

The role of the NH2 termini of angiotensin II (ANG II) and [Sar1]ANG II on conformation and activity were examined by proton NMR two-dimensional-J-correlated spectroscopy and one-dimensional nuclear Overhauser effect studies in the relatively nonpolar "receptor-simulating" environment provided by dimethyl sulfoxide-d6, using the biologically inactive COOH-terminal pentapeptide [des1,2,3]ANG II as control. Irradiation of C alpha H, C2H, and C4H proton resonances in ANG II and [Sar1]ANG II resulted in enhancements of Tyr and Phe ring proton resonances, indicating that the three aromatic rings cluster together. Very strong enhancements (17-22%) of the C alpha Y proton resonance in ANG II and [Sar1]ANG II upon irradiation of the C alpha H proton resonance, and vice versa, revealed that a Tyr-Ile-His bend is a predominant feature of the conformation of the two agonists. In contrast, saturation of the C alpha H and C alpha Y proton resonances in the control pentapeptide [des-1,2,3]ANG II did not produce, respectively, any C alpha Y or C alpha H proton nuclear Overhauser effect enhancement, illustrating the absence of a Tyr-Ile-His bend in the truncated ANG II peptide. The present findings indicate that the NH2-terminal domain of ANG II appears to have an essential role in generating the biologically active charge relay conformation of the hormone.

Algorithms↗
PubMed1994

Receptor interactions of the position 4 side chains of angiotensin II analogues: importance of aromatic ring quadrupole.

A triad of interacting groups (TyrOH-His-O2C) in angiotensin II (ANG II) has been postulated to create the tyrosinate anion pharmacophore (tyanophore) responsible for receptor activation/triggering (Biochim. Biophys. Acta 1991, 1065, 21). In the present study we investigated the effects on bioactivity of substituting the Tyr4 residue in [Sar1]ANG II with other anionic or electronegative amino acids, and with a number of aromatic amino acids lacking a hydroxyl group. [Sar1 Nva(delta-OH)4]ANG II, [Sar1 Nva(delta-OCH3)4]ANG II, [Sar1 Met4]ANG II, [Sar1 Gln4]ANG II, [Sar1 Glu4]ANG II and [Sar1 DL-Alg]ANG II had agonist activities in the rat isolated uterus assay of 4, 3, 19, 10, < 0.1 and < 0.1%, respectively, of that of ANG II. [Sar1 Nal4]ANG II, [Sar1 Pal4]ANG II, [Sar1 DL-Phg(4'-F)4]ANG II, [Sar1 Phe(4'-F)4]ANG II, [Sar1 Phe(F5)4]ANG II and [Sar1 His4]ANG II had agonist activities of 4.5, 7, < 0.1, 0.2, 1 and 0.6%, respectively. All peptides investigated were devoid of measurable antagonist activity except [Sar1 Phe(4'-F)4ANG II (pA2 = 7.7). These findings illustrate that anionic or electronegative aliphatic side chains replacing tyrosinate at position 4 can partially activate the angiotensin receptor. For ANG II analogues containing an aromatic amino acid other than Tyr at position 4, ligand binding and agonist activity are not dependent on the electronegativity or dipole moment of the aromatic ring, or on the ability of the 4' ring substituent to accept a proton.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1994

Designing peptide mimetics.

During this century, the nonpeptidic families of hormones (for example, steroids and catecholamines) have been exploited by medicinal chemists to give an array of clinically important drugs. Although peptides represent the largest class of hormonal substances, they are limited in their potential for treating a variety of diseases because of their lack of oral bioavailability and their short durations of action resulting from enzymic degradation in vivo. Recently, rapid screening of small molecule libraries and rational design approaches have produced peptide mimetics as a new generation of promising drug leads. In this review, Graham Moore provides some insight into aspects of the rational design approach to peptide mimicry using angiotensin II as an example.

Angiotensin II↗
PubMed1994

Transposition of the imidazole ring substituents of angiotensin mimetics related to Losartan.

A series of analogues related to Losartan in which the imidazole ring substituents were transposed have been prepared. Biological evaluation, both in vitro and in vivo, demonstrated that the orientation of the imidazole ring has a subtle yet significant effect upon the potency of these analogues. This information has provided an insight into the possible mode of receptor binding of Losartan and related compounds.

Angiotensin Receptor Antagonists↗
PubMed1993

Synthesis and biological activities of angiotensin II, Sarilesin, and Sarmesin analogues containing Aze or Pip at position 7.

Analogues of [Sar1]angiotensin II, Sarilesin (type I antagonist), and Sarmesin (type II antagonist) with L-azetidine-2-carboxylic acid (Aze) and L-pipecolic acid (Pip) at position 7 have been prepared by the solid-phase method, purified by reverse-phase HPLC, and bioassayed in the rat uterus. Analogues of the superagonist [Sar1]ANGII with Aze or Pip at position 7 and sarcosine (Sar) or aminoisobutyric acid (Aib) at position 1 had high intrinsic activity in the rat isolated uterus assay (34-184%). Analogues of Sarilesin ([Sar1,Ile8]ANGII) with Aze or Pip at position 7 and Sar or Aib at position 1 retained high antagonist activity (pA2 = 7.1-8.3). Analogues of Sarmesin ([Sar1,Tyr-(OMe)4]ANGII) with Aze and Pip at position 7 had pA2 values of 7.4 and 6.5, respectively. [Aze7]-ANGII and [Pip7]ANGII had low activities (12% and 1%, respectively), and deletion of Sar at position 1 of Sarmesin analogues abolished binding (or affinity) as judged from pA2 values. Nuclear Overhauser effect (NOE) spectroscopy studies of [Sar1,Aze7]ANGII in DMSO-d6 have indicated a clustering of the three aromatic rings (Tyr, His, Phe) and proximity of Sar C alpha and Arg C delta protons to the Tyr/Phe ring protons. These data emphasize that replacement of Pro with the lower and higher homologs Aze and Pip does not greatly alter the structural requirements necessary for expression of agonist or antagonist activity, when sarcosine occupies position 1, but not when Asp occupies position 1, suggesting that there is an intimate relationship between the N-terminal and penultimate residues of the molecule in the biologically active conformation of the molecule.

Angiotensin II↗
PubMed1993

Reciprocal modulation of the binding of angiotensin agonists and antagonists to angiotensin receptors in smooth muscle.

1. Direct ligand binding studies have shown that the agonist 125I-[Sar1]Ang II and the antagonist 125I-[Sar1Ile8]Ang II bind to bovine uterus smooth muscle membranes in a time-dependent, reversible and saturable manner; both ligands had the same number of high affinity sites. 2. [Sar1Ile8]Ang II inhibited the binding of 125I-[Sar1]Ang II in a non-competitive manner by decreasing the number of high affinity sites without changing the binding affinity of the radioligand. 3. [Sar1]Ang II also inhibited the binding of 125I-[Sar1Ile8]Ang II in a non-competitive manner. 4. Dissociation of both radioligands from their receptor sites was fast enough that pseudo irreversible occupancy of the binding sites could not account for the observed non-competitive inhibition. 5. Displacement studies using 125I-[Sar1Ile8]Ang II as the radioligand provided evidence for the existence of two binding sites when the displacing ligand was [Sar1]Ang II but not when the displacing ligand was [Sar1Ile8]Ang II. 6. GTPS gamma S had no discernible effect on the binding of either 125I-[Sar1]Ang II or 125I-[Sar1Ile8]Ang II to bovine uterine membranes. 7. The present findings are consistent with an allosteric mechanism of antagonism for [Sar1Ile8]Ang II. The data are also consistent with a mechanism wherein agonist and antagonist ligands occupy different binding modes at the same receptor site and induce long-term conformational changes in the receptor which are idiosyncratic with respect to the nature of the ligand. An emerging relationship between the actions of angiotensin peptides and non-peptide mimetics of angiotensin is presented.

1-Sarcosine-8-Isoleucine Angiotensin II↗
PubMed1993

Influence of methylation of the histidine ring of [Sar1]angiotensin II on conformation and biological activity.

[Sar1His(1-Me)6]ANG II and [Sar1His(3-Me)6]ANG II were synthesized by the solid-phase method and purified by reversed-phase HPLC. 1H-NMR spectroscopy at 400 MHz demonstrated the presence of two major conformers for both peptides in DMSO, representing cis and trans isomers (ratio 1:3 and 1:4, respectively) due to restricted rotation at the His-Pro bond. The contractile activities of these peptides in the rat isolated uterus assay were < 0.1 and 27% of that of ANG II, respectively. The bioactivities of these analogues were mirrored in their NMR spectra: the inactive analogue [Sar1His(1-Me)6]ANG II showed perturbations of the Sar and His residues which were not present for [Sar1His(3-Me)6]ANG II and the reference agonist [Sar1]ANG II. The high activity of the analogue methylated at His N3 suggests that an ionizable imidazole proton is not an absolute requirement for expression of biological activity by angiotensin ligands, and that the imidazole group in the molecule may function in an ion dipole-based mechanism when an intramolecular proton transfer (charge relay) mechanism is not available. The biological activity of the ligand appears to depend on the degree of proton transfer from Tyr-OH to the imidazole acceptor, wherein complete (formal) proton transfer represents 100% activity.

Angiotensin II↗
PubMed1993

Synthesis and biological activities of non-peptide angiotensin receptor antagonists with tetrazole replaced imidazole ring.

Angiotensin receptor antagonists related to losartan were synthesized in which the imidazole ring was replaced by tetrazole. 1-[4-(2'-Carboxyphenyl)benzyl]-5-butyl tetrazole and 5-[4-(2'-carboxyphenyl)benzyl]-1-butyl tetrazole had antagonist activities versus angiotensin II in the rat isolated uterus assay of 70% and 10%, respectively, of that of the equivalent imidazole compound 1-[4-(2'-carboxyphenyl)benzyl]-2-butyl imidazole. These data suggest that the antagonist activity of compounds in this class is not dependent on the direction of the heterocyclic ring dipole, and that there is a preference for substitution of the acid group-bearing side-chain at the N atom rather than the C atom of tetrazole.

Angiotensin Receptor Antagonists↗
PubMed1993

Imidazole based non-peptide angiotensin II receptor antagonists. Investigation of the effect of the orientation of the imidazole ring on biological activity.

Non-peptide angiotensin II receptor antagonists related to losartan (DuP 753, CAS 114798-26-4) were prepared and evaluated for antagonist activity in the rat isolated uterus assay. The synthetic strategy concentrated on changes in the orientation of the imidazole ring relative to the substituents, which were maintained in a similar pattern to that found in losartan. The results indicate that biological activity of such antagonists shows little dependence on the orientation of the imidazole ring, but that the spacing of the substituents of primary importance.

Acrylates↗
PubMed1993

Role of the amino- and carboxyl-terminal domains of thrombin receptor-derived polypeptides in biological activity in vascular endothelium and gastric smooth muscle: evidence for receptor subtypes.

Using guinea pig gastric longitudinal muscle (GLM) and rat gastric longitudinal muscle (RLM) contractile assays and a rat aortic ring (RA) endothelium-dependent relaxation assay, we have examined the biological activities of a number of human and rat thrombin receptor-derived polypeptides (TRPs) modified at amino-terminal and carboxyl-terminal residues. Our study focused primarily on the human pentapeptide [S42FLLR46 (P5)], previously shown to retain full thrombin-like activity. Whereas N-acetylation (N-acetyl-P5) abolished biological activity in the GLM and RA assays, amidation or esterification of the carboxyl-terminal carboxyl group [P5-NH2, P5-OCH3, or S42FLLRNP48-NH2 (P7-NH2)] enhanced peptide potency by about 10-fold in both the GLM and RA assays, compared with the unmodified TRPs (P5 and P7). Removal from P5 of either the amino-terminal hydroxyl group of serine (to yield A42FLLR46) or both the amino-terminal hydroxyl group and the primary amino group of P5 [to yield propionyl-F43LLR46 (Pr-P4)] produced peptides that were active in both the GLM and RA assays. Substitution of the carboxyl-terminal guanidinium group of P5 with a less basic primary amino acid residue (S42FLLK46) resulted in a peptide with a lower potency than that of P5 in the GLM and RA assays, whereas substitution of D-arginine for L-arginine at the carboxyl terminus abolished biological activity. Substitution of norleucine for arginine (S42FLLNorleuN) resulted in a peptide active in the GLM but not in the RA assay. For selected agonists (Pr-P4, P5, P7, and P7-NH2), the potencies in the GLM and RA assays, relative to that of P5, differed; for the GLM the order was P7-NH2 > P7 > P5 congruent to Pr-P4, whereas for the RA the order was P7-NH2 > or = Pr-P4 >> P5 > or = P7. Data comparable to those obtained with the GLM assay were also obtained with a RLM assay, wherein the potency series was P7-NH2 > P7 > P5. The relative potencies of pentapeptides based on the rat receptor sequence [SFFLR (Ra-P5), SFFLR-NH2 (Ra-P5-NH2), and SFFLRNP (Ra-P7)] differed in the RLM and RA assays. In the RLM the order was Ra-P5-NH2 > P7-NH2 > P5-NH2 > Ra-P7 = P7 > P5 = Ra-P5, whereas in the RA the relative potency series was P7-NH2 > P5-NH2 > Ra-P5-NH2 > Ra-P7 > P5 > or = P7 > Ra-P5.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗