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Biomedical subjects

T A Kerr

Publications and source records attributed to T A Kerr.

At least 19 recordsLinked to original sources
PubMed2000

Molecular basis for feedback regulation of bile acid synthesis by nuclear receptors.

The catabolism of cholesterol into bile acids is regulated by oxysterols and bile acids, which induce or repress transcription of the pathway's rate-limiting enzyme cholesterol 7alpha-hydroxylase (CYP7A1). The nuclear receptor LXRalpha binds oxysterols and mediates feed-forward induction. Here, we show that repression is coordinately regulated by a triumvirate of nuclear receptors, including the bile acid receptor, FXR; the promoter-specific activator, LRH-1; and the promoter-specific repressor, SHP. Feedback repression of CYP7A1 is accomplished by the binding of bile acids to FXR, which leads to transcription of SHP. Elevated SHP protein then inactivates LRH-1 by forming a heterodimeric complex that leads to promoter-specific repression of both CYP7A1 and SHP. These results reveal an elaborate autoregulatory cascade mediated by nuclear receptors for the maintenance of hepatic cholesterol catabolism.

Animals↗
PubMed1998

cDNA cloning of mouse and human cholesterol 25-hydroxylases, polytopic membrane proteins that synthesize a potent oxysterol regulator of lipid metabolism.

Oxysterols regulate the expression of genes involved in cholesterol and lipid metabolism and serve as intermediates in cholesterol catabolism. Among the most potent of regulatory oxysterols is 25-hydroxycholesterol, whose biosynthetic enzyme has not yet been isolated. Here, we report the cloning of cholesterol 25-hydroxylase cDNAs from the mouse and human. The encoded enzymes are polytopic membrane proteins of 298 and 272 amino acids, respectively, which contain clusters of histidine residues that are essential for catalytic activity. Unlike most other sterol hydroxylases, cholesterol 25-hydroxylase is not a cytochrome P450, but rather it is a member of a small family of enzymes that utilize diiron cofactors to catalyze the hydroxylation of hydrophobic substrates. The cholesterol 25-hydroxylase gene lacks introns, and in the human it is located on chromosome 10q23. The murine gene is expressed at low levels in multiple tissues. Expression of cholesterol 25-hydroxylase in transfected cells reduces the biosynthesis of cholesterol from acetate and suppresses the cleavage of sterol regulatory element binding protein-1 and -2. The data suggest that cholesterol 25-hydroxylase has the capacity to play an important role in regulating lipid metabolism by synthesizing a co-repressor that blocks sterol regulatory element binding protein processing and ultimately leads to inhibition of gene transcription.

Amino Acid Sequence↗
PubMed1991

Facial dyskinesia: a 16-year follow-up study.

The 109 female survivors of a mental hospital population surveyed in 1965 for facial dyskinesia were followed up 16 years later. The 99 survivors with non-organic brain syndromes were analysed. Prevalence of dyskinesia had risen from 18.4% to 46.5% during follow-up and its development was significantly associated with neuroleptic dosage. Enlarged ventricles on brain scans were significantly associated with dyskinesia, cognitive impairment and neuroleptic prescribing.

Affective Disorders, Psychotic↗
PubMed1986

Mortality and facial dyskinesia.

In 1965 a psychiatric in-patient population was surveyed for the prevalence of facial dyskinesia. The present investigation reports on their survival time. Among male and female patients with functional disorders (mostly schizophrenia) there was a strong association between moderate or severe facial dyskinesia and shortened survival, but no clinical factors were found to explain this. Mild facial dyskinesia in functional disorders was not associated with reduced life expectancy and may be attributable to the general effects of ageing rather than to a specific pathological process. Among patients with primary organic brain syndromes, dyskinesia was not associated with reduced life expectancy.

Aged↗
PubMed1984

Trazodone. A comparative clinical and predictive study.

The clinical efficacy and tolerability of trazodone and amitriptyline were compared in 74 hospital patients suffering from depressive illness. The daily doses of trazodone and amitriptyline were 150-300 mg and 75-225 mg, respectively, with half-strength capsules for patients over the age of 65 years. Twenty-five and 29 patients receiving trazodone and amitriptyline, respectively, completed the 6 week treatment period. Antidepressant activity was measured using the Hamilton Depression Rating Scale (HDRS), the Zung Scale of Depression, visual analogue scales and a Global Assessment Scale. Trazodone and amitriptyline were both effective but not statistically different from each other in terms of antidepressant action. Moreover, patients with neurotic or endogenous depression responded equally well on either treatment. Trazodone was less troublesome in respect of the persistent dry mouth and severe adverse psychiatric reactions which occurred with amitriptyline. Patients should be advised to take trazodone after meals.

Adult↗
PubMed1979

The comparative antidepressant value of lofepramine and amitriptyline. Results of a controlled trial with comments on the scales used.

A double-blind controlled trial comparing the antidepressant activity of amitriptyline with lofepramine is reported. Forty-six patients entered the 4-week trial. Analysis of the Hamilton Depression Rating Scale scores at the beginning and end of the trial showed no significant difference between the therapeutic efficacy of lofepramine and amitriptyline. However, patients with endogenous depression responded significantly more rapidly to lofepramine as measured by Visual Analogue Scales and showed a significantly greater degree of clinical improvement after 4 weeks' treatment, as measured by Global Assessment. Adverse effects were similar in the two treatment groups. The use of rating scales in trials of depressive illnesses is discussed. The Visual Analogue Scale for depression was found to be a simple, useful and valid measure.

Aged↗
PubMed1977

A clinical comparison of nomifensine and amitriptyline.

1. The study consists of a double-blind evaluation of nomifensine and amitriptyline in a group of 37 patients with primary depressive illness. 2. The patients were referred by their family doctors on the basis that they would ordinarily have been prescribed a tricyclic antidepressant drug. Random allocation to the treatment groups took place. Assessment took place at weekly intervals over a 4-week period using the Visual Analogue Scale for depression and anxiety, and a side-effects check-list. Patients were also assessed on the Hamilton Depression Scale before the onset and at the end of the trial. 3. No significant difference was found between the two groups as regards relief from depression and anxiety, although marginal differences were found in favour of the amitriptyline group. 4. The overall frequency of side-effects was similar in the nomifensine and amitriptyline patients, But the development of severe side-effects was significantly more common in the amitriptyline group.

Adjustment Disorders↗