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Biomedical subjects

S Brandon

Publications and source records attributed to S Brandon.

At least 19 recordsLinked to original sources
PubMed1992

Synthesis of a yohimbine-agarose matrix useful for large-scale and micropurification of multiple alpha 2-receptor subtypes.

We have provided a detailed protocol for the synthesis of a yohimbine-agarose matrix that has been shown to be effective for isolation of the alpha 2A-adrenergic receptor from human platelet and purification of the alpha 2A-adrenergic receptor to apparent homogeneity from porcine brain cortex using chromatography on only two sequential yohimbine-agarose columns. In addition, this affinity matrix also interacts with alpha 2 receptors of the alpha 2B subtype extracted from cultured NG108-15 cells. Finally, this affinity matrix has proven useful for monitoring posttranslational modifications of the receptor in digitonin extracts of metabolically labeled cells. Thus, this affinity matrix can be exploited for the purification of multiple alpha 2-adrenergic receptor subtypes on both a macro- and microscale and should be of value to any laboratory exploring the molecular basis for alpha 2-adrenergic functions.

Adrenergic alpha-Agonists↗
PubMed1992

Who benefits from electroconvulsive therapy? Combined results of the Leicester and Northwick Park trials.

This paper describes the results obtained by combining data from the Northwick Park and Leicester randomised controlled trials of ECT. Patients who suffered from depression in which retardation and delusions were features and who received real ECT had a significantly improved outcome at the end of four weeks of treatment (as measured by improvement in the HRSD) in comparison with those who received simulated ECT. However, this treatment effect was not detectable at six-month follow-up. Patients who were neither retarded nor deluded did not benefit significantly from real as opposed to simulated ECT.

Antidepressive Agents↗
PubMed1991

Subtyping panic disorder by major depression and avoidance behaviour and the response to active treatment.

In order to establish the clinical validity of currently used ways of subtyping panic disorder the predictive power of associated current avoidance behaviour and (secondary) major depression for the response to active treatment (alprazolam, imipramine) was tested. The analysis was based on the data from the Cross-National-Collaborative-Panic-Study. Limited support for validity evidenced by predicting drug response was found for grading panic disorder by the severity of avoidance behaviour; patients with panic attacks and agoraphobia are more responsive to imipramine (compared with alprazolam) when using the reduction of the total number of panic attacks (or of spontaneous panic attacks) as the outcome criterion; patients without any avoidance behaviour did better with alprazolam (compared with imipramine).

Adult↗
PubMed1991

Avoidance behaviour: a predictor of the efficacy of pharmacotherapy in panic disorder?

The impact of the avoidance behaviour on the psychopharmacological treatment of panic disorder was explored in the Cross National Collaborative Panic Study (n = 1134 patients); in this double blind randomized trial alprazolam, imipramine and placebo were compared during an 8-week treatment period. Patients with extensive avoidance behaviour (agoraphobia) had the most profit from the active drugs. Counter expectancy these specific drug effects were most pronounced in avoidance behaviour. Active drugs (in particular imipramine) were especially more effective than placebo if the patients presented with associated avoidance behaviour. The results suggest that agoraphobia defines more a particular type of anxiety disorder overlapping with panic disorder than merely a severe state of panic disorder.

Adult↗
PubMed1991

Monovalent cation and amiloride analog modulation of adrenergic ligand binding to the unglycosylated alpha 2B-adrenergic receptor subtype.

The unglycosylated alpha 2B subtype of the alpha 2-adrenergic receptor found in NG-108-15 cells possesses allosteric regulation of adrenergic ligand binding by monovalent cations and 5-amino-substituted amiloride analogs. These findings demonstrate that allosteric modulation of adrenergic ligand binding is not a property unique to the alpha 2A subtype. The observation that amiloride analogs as well as monovalent cations can modulate adrenergic ligand binding to the nonglycosylated alpha 2B subtype indicates that charge shielding due to carbohydrate moieties does not play a role in this allosteric modulation but, rather, these regulatory effects result from interactions of cations and amiloride analogs with the protein moiety of the receptor. Furthermore, the observation that both alpha 2A and alpha 2B receptor subtypes are modulated by amiloride analogs suggests that structural domains that are conserved between the two are likely to be involved in this allosteric modulation.

Amiloride↗
PubMed1990

An aspartate conserved among G-protein receptors confers allosteric regulation of alpha 2-adrenergic receptors by sodium.

The residue involved in sodium regulation of G-protein-coupled receptors has been identified by site-directed mutagenesis of the alpha 2-adrenergic receptor gene. Mutation of Asp-79 to Asn-79 entirely eliminates allosteric regulation of ligand binding by monovalent cations without perturbing the selectivity of adrenergic binding or allosteric modulation of that binding by amiloride analogs. The high degree of conservation of this aspartate residue in all G-protein-coupled receptors, without even a conservative change to glutamate, underscores the probable importance of this allosteric regulation.

Affinity Labels↗
PubMed1989

NHS indemnity.

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Humans↗
PubMed1989

Avoidance behaviour and major depression in panic disorder: a report from the Cross-National Collaborative Panic Study.

Avoidance behaviour and secondary major depression are both frequent in clinical samples of patients with panic disorder. Their status is unclear: indicators of severity of panic disorder or indicators of separate psychiatric disorders. Among the data of the Cross-National Collaborative Panic Study (n = 1,168) we found that especially avoidance behaviour defines more severe states of panic disorder (earlier age at onset, higher frequency of panic attacks and higher level of psychopathology); co-occurrence of major depression is less clearly associated with more severe panic disorder. The results are compatible with the DSM-III-R concepts of comorbidity of panic disorder and major depression and of subtyping panic disorder by avoidance behaviour.

Adult↗
PubMed1988

Preliminary report of a community survey of panic attacks and panic disorder.

This study looked at the prevalence of panic attacks and panic disorder in a British population. Three thousand people (aged 18-65) registered with a Leicester general practice were sent a postal questionnaire which screened for panic attacks. Where appropriate this was followed by a diagnostic interview. Preliminary results are reported for the first 1500 subjects sampled. Panic attacks are a common experience in the study population (7.5% of responders experienced them around the time of the interview). Panic disorder was diagnosed in about 3% of responders.

Adult↗
PubMed1988

The classification of anxiety disorders.

This paper discusses the relationship between panic and other symptoms of anxiety disorders. The approach to classification of these disorders described in the Diagnostic and Statistical Manual of Mental Disorders (Third Edition) of the American Psychiatric Association is outlined. It is concluded that there are substantial advantages to the adoption of such a system. Not only does the separation of distinct syndromes offer some understanding of aetiology but there is evidence of a differential treatment response.

Adolescent↗
PubMed1987

Regulation of porcine brain alpha 2-adrenergic receptors by Na+,H+ and inhibitors of Na+/H+ exchange.

Previous reports from this laboratory have demonstrated that alpha 2-adrenergic receptors accelerate Na+/H+ exchange in NG108-15 neuroblastoma X glioma cells and evoke platelet secretion via a pathway involving Na+/H+ exchange. The present studies were designed to examine whether agents that interact with Na+/H+ antiporters also might influence alpha 2-adrenergic receptor-ligand interactions. We observed that Na+ decreases receptor affinity for the agonists epinephrine, norepinephrine, and UK14304 and slightly increases receptor affinity for the antagonists yohimbine and idazoxan in digitonin-solubilized preparations from porcine brain cortex. Increases in [H+] also decrease receptor affinity for agonists and cause either a slight increase or no change in receptor affinity for antagonists. Amiloride analogs accelerate the rate of [3H] yohimbine dissociation from digitonin-solubilized receptors with a relative effectiveness that parallels their ability to block Na+/H+ exchange in other systems. Interestingly, these modulatory effects of Na+,H+ and 5-amino-substituted analogs of amiloride are retained in homogeneous preparations of the alpha 2-adrenergic receptor, suggesting that the allosteric-binding sites for these agents are on the receptor-binding protein itself.

Amiloride↗