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M Rowley

Publications and source records attributed to M Rowley.

At least 37 records · Page 2Linked to original sources
PubMed1998

3-(1-piperazinyl)-4,5-dihydro-1H-benzo[g]indazoles: high affinity ligands for the human dopamine D4 receptor with improved selectivity over ion channels.

3-(4-Piperidinyl)-5-arylpyrazoles, such as 1, were selective for the cloned human dopamine D4 receptor (hD4), but also showed affinity at voltage sensitive calcium, sodium and potassium ion channels. A combination of substituent changes to reduce the basicity of the piperidine nitrogen and conformational restriction to give 4,5-dihydro-1H-benzo[g]indazoles reduced this ion channel affinity at the expense of selectivity for hD4 over other dopamine receptors. Incorporation of piperazine into the 4,5-dihydro-1H-benzo[g]indazoles in place of piperidine gave a novel series of high affinity, selective, orally bioavailable hD4 ligands, such as 16, with improved selectivity over ion channels.

Administration, Oral↗
PubMed1998

Substituted pyrazoles as novel selective ligands for the human dopamine D4 receptor.

Two novel series of 3-(heterocyclylmethyl)pyrazoles have been synthesised and evaluated as ligands for the human dopamine D4 receptor. Compounds in series I (exemplified by 8k) have a phenyl ring joined to the 4-position of the pyrazole while those in series II (exemplified by 15j) have a 5-phenyl ring linked by a saturated chain to the 4-position of the pyrazole. Both series supplied compounds with excellent affinity for the human D4 and good selectivity over other dopamine receptors. Excellent selectivity over calcium, sodium, and potassium ion channels was also achieved.

Antipsychotic Agents↗
PubMed1997

Effect of plasma protein binding on in vivo activity and brain penetration of glycine/NMDA receptor antagonists.

A major issue in designing drugs as antagonists at the glycine site of the NMDA receptor has been to achieve good in vivo activity. A series of 4-hydroxyquinolone glycine antagonists was found to be active in the DBA/2 mouse anticonvulsant assay, but improvements in in vitro affinity were not mirrored by corresponding increases in anticonvulsant activity. Here we show that binding of the compounds to plasma protein limits their brain penetration. Relative binding to the major plasma protein, albumin, was measured in two different ways: by a radioligand binding experiment or using an HPLC assay, for a wide structural range of glycine/NMDA site ligands. These measures of plasma protein binding correlate well (r = 0.84), and the HPLC assay has been used extensively to quantify plasma protein binding. For the 4-hydroxyquinolone series, binding to plasma protein correlates (r = 0.92) with log P (octanol/pH 7.4 buffer) over a range of log P values from 0 to 5. The anticonvulsant activity increases with in vitro affinity, but the slope of a plot of pED50 versus pIC50 is low (0.40); taking plasma protein binding into account in this plot increases the slope to 0.60. This shows that binding to albumin in plasma reduces the amount of compound free to diffuse across the blood-brain barrier. Further evidence comes from three other experiments: (a) Direct measurements of brain/blood ratios for three compounds (2, 16, 26) show the ratio decreases with increasing log R. (b) Warfarin, which competes for albumin binding sites dose-dependently, decreased the ED50 of 26 for protection against seizures induced by NMDLA. (c) Direct measurements of brain penetration using an in situ brain perfusion model in rat to measure the amount of drug crossing the blood-brain barrier showed that compounds 2, 26, and 32 penetrate the brain well in the absence of plasma protein, but this is greatly reduced when the drug is delivered in plasma. In the 4-hydroxyquinolones glycine site binding affinity increases with lipophilicity of the 3-substituent up to a maximum at a log P around 3, then does not improve further. When combined with increasing protein binding, this gives a parabolic relationship between predicted in vivo activity and log P, with a maximum log P value of 2.39. Finally, the plasma protein binding studies have been extended to other series of glycine site antagonists, and its is shown that for a given log P these have similar protein binding to the 4-hydroxyquinolones, except for compounds that are not acidic. The results have implications for the design of novel glycine site antagonists, and it is suggested that it is necessary to either keep log P low or pKa high to obtain good central nervous system activity.

Animals↗
PubMed1997

4-Heterocyclylpiperidines as selective high-affinity ligands at the human dopamine D4 receptor.

5-(4-Chlorophenyl)-3-(1-(4-chlorobenzyl)piperidin-4-yl)pyrazole (3) was identified from screening of the Merck sample collection as a human dopamine D4 (hD4) receptor ligand with moderate affinity (61 nM) and 4-fold selectivity over human D2 (hD2) receptors. Four separate parts of the molecule have been examined systematically to explore structure-activity relationships with respect to hD4 affinity and selectivity over other dopamine receptors. It was found that the 4-chlorophenyl group attached to the pyrazole is optimal, as is the 4-substituted piperidine. The lipophilic group on the basic nitrogen is more amenable to change, with the optimal group found to be a phenethyl. The aromatic heterocyle can be altered to a number of different groups, with isoxazoles and pyrimidines showing improved affinities. This heterocycle can also be advantageously alkylated, improving the selectivity of the compounds over D2 receptors. It is hypothesized that the conformation around the bond joining the aromatic heterocycle to the piperidine is important for D4 affinity, based on crystal structures of isoxazoles (29 and 30) and on a conformationally constrained compound (28). Putting all the favorable changes together led to the discovery that 5-(4-chlorophenyl)-4-methyl-3-(1-(2-phenylethyl)piperidin-4-yl)iso xazole (36) is a nanomolar antagonist at human dopamine D4 receptors with > 500-fold selectivity over hD2 and > 200-fold selectivity over hD3. Compound 36 is an antagonist of hD4 receptors with good oral bioavailability of 38%, a half life of 2 h, and brain levels 10-fold higher than plasma levels.

Cell Line↗
PubMed1996

HLA-DR, DQ and anti-GAD antibodies in first degree relatives of type I diabetes mellitus.

The differential antibody response to glutamic acid decarboxylase (anti-GAD) and to islet cell cytoplasm (ICA) according to HLA-DR and DQ genotypes were examined in 28 Spanish patients with Type I diabetes mellitus (11.1 +/- 10.4 year diabetes duration) and their 41 first degree non-diabetic relatives. Anti-GAD was detected by radioimmunoprecipitation and ICA by indirect immunofluorescence and HLA-DR/DQ alleles were assigned by PCR and sequence specific oligonucleotide probes. The frequency in patients of positivity for ICA was 7.1% and of anti-GAD+ 64.3%, and in relatives, the frequency of ICA+ was 4.9%, and anti-GAD+ 9.8%. Concurrent positivity for ICA and anti-GAD existed in only one patient, and in none of the relatives. We confirm for a Spanish population the high frequency of risk genotypes for Type I, involving DR3, DR4 and DQB1*0302 (DQ8) which were present in 26 of 28 (93%) patients and 32 of 41 (78%) relatives. The most frequent genotypes were DR3/DQB1*0201/DQA1*0501-DR4/DQB1*0302/DQA1*0301( 9 patients, 32%; 6 relatives, 15%), DR3/DQB1*0201/ DQA1*0501-DR3/DQB1*0201/DQA1*0501 (5 patients, 18%; 7 relatives, 17%) and DE3/DQB1*0201/DQA1*0501-DR1/ DQB1*0501/DQA1*0101(5 patients, 18%; 1 relative, 2%). Positivity for anti-GAD or for ICA did not correlate with gender, or age at onset or duration of DM. The distribution of high risk HLA genotypes were similar regardless the anti-GAD or anti-ICA status either in patients or in their relatives.

Adolescent↗
PubMed1996

The low prevalence of immunogenetic markers in Korean adult-onset IDDM patients.

OBJECTIVE: IDDM is an autoimmune disease that occurs among genetically susceptible individuals. In Asian populations, it is not uncommon for adult patients with NIDDM to eventually lose beta-cell function and develop IDDM. These individuals may be characterized by autoantibodies to GAD and high-risk HLA-DQ alleles, which are unlikely to be prevalent among patients with true NIDDM or in the general population. The objective of the present study was to evaluate and compare the prevalence of these immunogenetic markers in NIDDM patients and healthy nondiabetic individuals from Korea. RESEARCH DESIGN AND METHODS: The prevalences of anti-GAD antibodies and HLA-DQA1 and DQB1 alleles among 121 patients with newly diagnosed NIDDM identified from a population-based study in Yonchon, Korea, and 100 matched healthy control subjects were evaluated and compared. RESULTS: The overall prevalence of anti-GAD antibodies was 1.7% (2 of 121) in patients with previously undiagnosed NIDDM, whereas 1 of 100 control subjects had a positive test for antibodies. Among those who tested positive, titers of antibodies to GAD were not high. No statistically significant differences in the distributions of either mean levels of anti-GAD antibodies or DQA1 and DQB1 alleles were found comparing NIDDM patients with control subjects. Interestingly, the frequency of DQB1*non-Asp-57 and DQA1*Arg-52 alleles in the Korean adult control population was similar to that in the U.S. white population (DQB1*non-Asp-57: 0.431 vs. 0.475; DQA1*Arg-52: 0.492 vs. 0.463). CONCLUSIONS: The low prevalence of anti-GAD antibodies and HLA-DQA1 and DQB1 susceptibility alleles among recent-onset NIDDM patients, which was similar to observations in control subjects, suggests that diabetes in Korean adults is unlikely to have an autoimmune component to its pathogenesis.

Adult↗
PubMed1996

Lack of autoantibody expression in children born to mothers with silicone breast implants.

OBJECTIVE: We determined systematically the prevalence of autoantibodies in children born to mothers with silicone breast implants and the relationships with clinical symptoms and methods of exposure. METHODS: Autoantibody expression was determined in 80 children born to mothers with silicone implants and in 42 controls. A clinical assessment score was assigned to each patient. Antinuclear antibodies as well as antibodies to mitochondrial, smooth muscle, striational, myocardial, parietal cell, reticulin tissues, or subcellular compartments were measured by indirect fluorescent assay. Antibodies to nRNP (U1-RNP/snRNP); Sm; SS-A; SS-B; Scl-70; thyroid microsome; immunoglobulin (Ig)G, IgM, and IgA antibodies to cardiolipin; and antibodies to native and denatured human types I and II collagen were measured by enzyme-linked immunosorbent assay. Serum complement components C3 and C4 and IgM rheumatoid factor were measured by nephelometry. RESULTS: Autoantibody prevalence was not significantly different between children born to mothers with silicone implants and controls. The presence of autoantibodies was not related to the children's clinical symptoms or to the method of exposure. CONCLUSIONS: Determination of autoantibody production is of limited clinical utility in the evaluation of children born to mothers with silicone breast implants.

Adolescent↗
PubMed1995

Detection and characterization of seven novel protein S (PROS) gene lesions: evaluation of reverse transcript-polymerase chain reaction as a mutation screening strategy.

The molecular genetic analysis of protein S deficiency has been hampered by the complexity of the protein S (PROS) gene and by the existence of a homologous pseudogene. In an attempt to overcome these problems, a reverse transcript-polymerase chain reaction (RT-PCR) mutation screening procedure was developed. However, the application of this mRNA-based strategy to the detection of gene lesions causing heterozygous type I protein S deficiency appears limited owing to the high proportion of patients exhibiting absence of mRNA derived from the mutation-bearing allele ("allelic exclusion"). Nevertheless, this strategy remains extremely effective for rapid mutation detection in type II/III protein S deficiency. Using the RT-PCR technique, a G-to-A transition was detected at position +1 of the exon IV donor splice site, which was associated with type I deficiency and resulted in both exon skipping and cryptic splice site utilization. No abnormal protein S was detected in plasma from this patient. A missense mutation (Asn 217 to Ser), which may interfere with calcium binding, was also detected in exon VIII in a patient with type III protein S deficiency. A further three PROS gene lesions were detected in three patients with type I deficiency by direct sequencing of exon-containing genomic PCR fragments: a single base-pair (bp) deletion in exon XIV, a 2-bp deletion in exon VIII, and a G0to-A transition at position -1 of the exon X donor splice site all resulted in the absence of mRNA expressed from the disease allele. Thus, the RT-PCR methodology proved effective for further analysis of the resulting protein S-deficient phenotypes. A missense mutation (Met570 to Thr) in exon XIV of a further type III-deficient proband was subsequently detected in this patient's cDNA. No PROS gene abnormalities were found in the remaining four subjects, three of whom exhibited allelic exclusion. However, the father of one such patient exhibiting allelic exclusion was subsequently shown to carry a nonsense mutation (Gly448 to Term) within exon XII.

Base Sequence↗
PubMed1995

Allosteric modulation of the glutamate site on the NMDA receptor by four novel glycine site antagonists.

Using radioligand binding studies, we have investigated the binding properties of four 4-hydroxy-2-quinolones, a novel series of selective antagonists for the glycine site on the N-methyl-D-aspartate (NMDA) receptor. L-701,324, L-703,717, L-698,532 and L-695,902 inhibited [3H]L-689,560 (glycine site antagonist) binding to rat cortex/hippocampus P2 membranes with IC50 values of 1.97, 4.47, 209 and 6448 nM, respectively, whilst also inhibiting non-equilibrium [3H]dizocilpine binding to the NMDA receptor ion-channel. All four compounds partially inhibited L-[3H]glutamate (approximately 50% inhibition; agonist) binding and enhanced [3H]cis-4-phosphonomethyl-2-piperidine carboxylate ([3H]CGS-19755; 41-81% enhancement; 'C-5' antagonist) and [3H]3-(2-carboxypiperazin-4-yl)-propyl-1-phosphonate ([3H]CPP; 28-66% enhancement; 'C-7' antagonist) binding to the glutamate recognition site of the NMDA receptor with EC50 values similar to those observed for [3H]L-689,560 binding. These results provide further evidence for allosteric interactions between the glutamate and glycine recognition sites of the NMDA receptor complex, and as the 4-hydroxy-2-quinolones are 'full' antagonists at the glycine site, indicate that these interactions are not caused by the intrinsic activity of a compound.

Allosteric Site↗
PubMed1994

The anticonvulsant and behavioural profile of L-687,414, a partial agonist acting at the glycine modulatory site on the N-methyl-D-aspartate (NMDA) receptor complex.

1. The anticonvulsant and behavioural effects of the glycine/NMDA receptor partial agonist, L-687,414 (R(+)-cis-beta-methyl-3-amino-1-hydroxypyrrolid-2-one) have been investigated in rodents. 2. L-687,414 dose-dependently antagonized seizures induced by N-methyl-D,L- aspartic acid (NMDLA, ED50 = 19.7 mg kg-1), pentylenetetrazol (PTZ, ED50 = 13.0 mg kg-1) and electroshock (ED50 = 26.1 mg kg-1) when given intravenously 15 min before test, in male Swiss Webster mice but was most potent against audiogenic seizures induced by a 120 dB bell in DBA/2 mice (ED50 = 5.1 mg kg-1, i.p., 30 min before test). 3. L-687,414 also induced impairments of performance in a rotarod test in both Swiss Webster and DBA/2 mice and the ratio [rotarod MED:anticonvulsant ED50] varied between 0.9 and 5, depending on the convulsant used. 4. Similar behaviours to those seen after administration of the non-competitive NMDA receptor antagonist, MK-801 (head weaving, body rolling, hyperlocomotion) were seen in the mouse after giving L-687,414, although the peak effect occurred at a dose (100 mg kg-1) which was 5-20 times the anticonvulsant ED50S, depending on the convulsant used. Unlike MK-801, however, doses of L-687,414 that were behaviourally stimulant did not increase dopamine turnover in the nucleus accumbens. 5. Consistent with the interaction of L-687,414 with the glycine/NMDA receptor, the anticonvulsant, ataxic and motor stimulant effects of the compound were significantly attenuated by the glycine/NMDA receptor agonist, D-serine (10-100 micrograms per mouse, i.c.v.). 6. The results show that L-687,414 is a potent, orally active anticonvulsant with a more benign pharmacological profile than antagonists acting at the ion channel of the NMDA receptor complex. The compound is a useful tool with which to probe the functional role of the glycine co-agonist site in vivo.

Animals↗
PubMed1994

A descriptive study of community input into the evolution of John Hunter Hospital Birth Centre: results of 'open entry' criteria.

The key feature of John Hunter Hospital Birth Centre is that consumer input influences the philosophy and protocols of the unit through a management executive. The executive includes representatives from all groups who use the Birth Centre, including general practitioners, visiting midwives, obstetricians and staff midwives, as well as 50% consumer representation. This has resulted in a unique Birth Centre with open and flexible entry criteria. Since its opening in February 1991, 1,492 women have been admitted to John Hunter Hospital Birth Centre, and of these 1,221 (82%) gave birth there. This figure is greater than any other Birth Centre utilization rate in Australia (1-4). An examination of outcomes for 1992 indicates that neither the higher than usual utilization rate nor the open entry criteria has compromised safety for either women or their infants.

Community Participation↗
PubMed1994

Antibodies to type II collagen in human serum: storage effects and role of IgM antiidiotype in regulation.

OBJECTIVE: To investigate the observation that IgG reactivity to human denatured type II collagen (denatured CII) is increased in normal human serum stored at 4 degrees C compared to serum stored at -20 degrees C. METHODS: Reactivity was measured by ELISA, and the effect of heating was also assessed. Serum was separated on affinity columns and mixing experiments were performed with the resultant fractions to test for inhibitory or enhancing effects. RESULTS: There is a storage labile and heat labile inhibitor in the IgG depleted fraction of serum stored at -20 degrees C from healthy subjects, and an inhibitor is present in some pooled human IgM preparations which reduces the reactivity of antibody to human CII in serum from both healthy subjects and patients with rheumatoid arthritis. CONCLUSIONS: Storage conditions and heat significantly affect IgG antibodies to denatured CII but not antibodies to other antigens. These effects may be mediated by the presence of an IgM antiidiotype against the IgG antibody to denatured CII.

Antibodies, Anti-Idiotypic↗
PubMed1993

3-Acyl-4-hydroxyquinolin-2(1H)-ones. Systemically active anticonvulsants acting by antagonism at the glycine site of the N-methyl-D-aspartate receptor complex.

Most full antagonists at the glycine site of the NMDA receptor contain a carboxylic acid, which we believe to be detrimental to penetration of the blood-brain barrier. By consideration of a pharmacophore, novel antagonists at this site have been designed in which the anionic functionality is a vinylogous acid, in the form of a 4-hydroxyquinolin-2(1H)-one. In this series, a 3-substituent is necessary for binding, and correct manipulation of this group leads to compounds such as the 3-(3-hydroxyphenyl)propargyl ester 24 (L-701,273), with an IC50 for displacement of [3H]-L-689,560 binding of 0.17 microM and Kb against NMDA in the cortical slice of 1.39 microM. Compounds were tested for their ability to prevent audiogenic seizure in DBA/2 mice; the most potent compound in this series is the cyclopropyl ketone 42 (L-701,252), with an ED50 of 4.1 mg/kg ip. A model is proposed for binding to the glycine site, in which an important interaction is of a putative receptor cation with the pi-system of the 3-substituent.

Acylation↗
PubMed1993

Invalidity from nonparallelism in a radioimmunoassay for erythropoietin accounted for by human serum antibodies to rabbit IgG.

An immunologic crossreactant of erythropoietin seemed to develop and persist in serum samples from a patient during treatment and remission of idiopathic aplastic anemia. It had a steeper slope to radioimmunoassay log-dose response lines and a larger molecular size than erythropoietin. On fractionation of serum, the apparent crossreactant was bound by staphylococcal Protein A at pH 7.5 and recovered by elution from it at pH 3.0. Adsorption of serum from the patient, and from one of two similarly affected children, with rabbit IgG linked to agarose appeared to remove completely the apparent crossreactant. These treated sera gave radioimmunoassay log-dose response lines essentially parallel to that given by the International Reference Preparation (IRP) for erythropoietin and estimates of immunoreactive erythropoietin appropriate to the normal hemoglobin concentrations. The apparent crossreactant of erythropoietin is thus accounted for by heterophilic antibodies to rabbit IgG. These developed in the patient following treatment with rabbit antilymphocyte globulin but seem to have arisen spontaneously in the children. Thus iatrogenic and idiopathic antibodies to rabbit IgG interfered in a radioimmunoassay for erythropoietin in serum through their ability to react with the radioimmunoassay anti-erythropoietin antiserum raised in rabbits.

Adult↗
PubMed1992

Antimitochondrial antibodies in kindreds of patients with primary biliary cirrhosis: antimitochondrial antibodies are unique to clinical disease and are absent in asymptomatic family members.

The 2-oxo-acid dehydrogenase family of enzymes have been identified as the major mitochondrial autoantigens of primary biliary cirrhosis. Using immunoblotting, enzyme-linked immunosorbent assay and enzyme inhibition with both purified mitochondrial proteins and recombinant autoantigens, we have studied family members and spouses of patients with primary biliary cirrhosis for the presence of antimitochondrial antibodies. Antimitochondrial antibodies and other common autoantigens were also tested for by indirect immunofluorescence. This study included 27 index patients with primary biliary cirrhosis, 15 spouses and 48 first- and second-degree relatives. Overall, 7 relatives (11%) were positive for autoantibodies to nuclear and cytoplasmic antigens by indirect immunofluorescence against mouse liver and stomach sections. However, with immunofluorescence, the reactivity strictly paralleled that of antimitochondrial antibodies in only one of these (1:640)--a sibling with mild pruritus and a liver biopsy specimen diagnostic of primary biliary cirrhosis despite normal levels of serum alkaline phosphatase. In addition, one of the mothers, who had a history of sarcoidosis, was positive by immunoblotting for antibodies to the E2 subunit of the pyruvate dehydrogenase complex and protein X. All other relatives were negative for all of the assays. Antibodies to neither the 2-oxo-acid dehydrogenase enzymes nor the recently proposed family of naturally occurring mitochondrial antibodies were found in spouses or healthy relatives. Three other first-degree relatives suffered from liver disease: two died (one from primary biliary cirrhosis and the other from an unknown type of liver disease) and one (a sibling with primary biliary cirrhosis) was unavailable for testing. Our results are consistent with a familial predisposition to primary biliary cirrhosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Serum immunoreactive erythropoietin in patients with idiopathic aplastic and Fanconi's anaemias.

In patients with idiopathic aplastic anaemia (n = 34) and Fanconi's anaemia (n = 8), sampled once or on several occasions, serum erythropoietin (Epo) increased with increasing severity of anaemia with apparently similar rates of increase in each group. However, after adjustment for Hb, log Epo values for the Fanconi's anaemics tended to be greater than those for the idiopathic aplastic anaemics (P < 0.01). Erythropoietin concentrations in serum samples from patients with Fanconi's and idiopathic aplastic anaemias tended to be greater than in samples from patients with anaemias from protein energy malnutrition, myelodysplasia and iron deficiency. The results suggest that there is no deficiency of erythropoietin in Fanconi's and idiopathic aplastic anaemias and that if exogenous erythropoietin is of any benefit it would need to be administered in doses large enough to induce a significant increase in log Epo. Results of the study illustrate the need to take account of the assumptions which underlie interpretation of the statistical analysis. Use of erythropoietin values in place of log Epo gives misleading conclusions demonstrable as invalid as the conditions for normality of distribution of the data and homogeneity of variances were not satisfied.

Adolescent↗