Dextran sodium sulfate inhibition of real-time polymerase chain reaction amplification: a poly-A purification solution

BACKGROUND

Dextran sulfate sodium (DSS) induces experimental colitis and promotes colitis-associated cancer in rodents. Here we document potent inhibition of real-time quantitative polymerase chain reaction (qPCR) using cDNA from DSS-exposed mouse tissues, which complicates gene expression analysis.

METHODS

We characterize DSS inhibition of qPCR in-vitro and in a wide array of murine tissues following ingestion of DSS. We examine different approaches to RNA purification prior to cDNA synthesis in order to optimize real-time polymerase chain reaction amplification and gene expression analysis.

RESULTS

DSS inhibits qPCR amplification of cDNA between 1 and 10 nM. Orally administered DSS interferes with qPCR amplification of cDNA derived from multiple tissues. Poly-A purification of DSS-exposed RNA allows reliable and cost-effective gene expression analysis in DSS-exposed tissue.

CONCLUSIONS

DSS is a potent inhibitor of real-time qPCR amplification and interferes with tissue-specific gene expression analysis in DSS-exposed mice. Poly-A purification of tissue-derived RNA results in reliable and cost-effective gene expression analysis in DSS-exposed mice.

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.

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.

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.

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.

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.

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.

Videotape technique in assessing antidepressants

1 In the search for superior levels of objectivity in research in clinical psychiatry videotape (VT), recordings were made of all clinical interviews with the first eleven patients entering a double-blind controlled trial of antidepressant drugs.

2 The treating psychiatrist recorded diagnosis as listed in the ICD and described in its accompanying Glossary, and rated the Hamilton Depression Scale (HDS) at pretreatment and final interviews. A Visual Analogue Scale (VAS) for depression was independently scored by psychiatrist and patient at each interview.

3 VT recordings were despatched for independent repetition of diagnostic assessment and ratings of mood (HDS and VAS) by two further psychiatrists, creating in effect a multiple-blind study.

4 Agreement was satisfactory on ICD listed diagnoses and complete for the broad category of `affective disorder'.

5 Between the three psychiatrists, there was a high correlation of HDS scores. Patients were independently agreed to form a group of moderately depressed subjects. Closely related degrees of improvement were recorded by the three psychiatrists in all patients.

6 Correlation of scores were high for the VAS for depression as independently scored by patient, treating psychiatrist and the two VT viewers.

7 The VAS was shown to be a simple, quick and reliable indicator of depressive mood suited to repeated use at short intervals.

8 VT recordings are a useful tool in the search for higher levels of objectivity in clinical research. The technique described might well become as accepted in psychiatric drug trials as the blind control procedure.

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.

Prediction of outcome in anxiety states and depressive illnesses

In a number of previous papers in this series (Roth et al., 1972; Gurney et al., 1972; Kerr et al., 1972; Schapira et al., 1972) evidence was adduced to suggest that depressive illnesses and anxiety states could be clinically differentiated from one another. It was shown also that with the aid of appropriate statistical techniques patients exhibiting these disorders could be separated into two distinct groups with relatively little overlap. The possibility that these findings were due to diagnostic preconceptions or other forms of bias was excluded by the results of follow-up studies conducted over an average period of 3.8 years in which the outcome of the entire patient population was evaluated by independent observers. The clinical picture found was consistent over the period of observation, with little diagnostic interchange between the groups. Moreover, the outcome of the depressions was significantly better than that of the anxiety states, and this provided external and independent validation of the view that the groups initially separated with the aid of clinical observation were indeed distinct from one another.

Studies in the classification of affective disorders. The relationship between anxiety states and depressive illnesses. II

This is the second of two papers dealing with the classification of affective disorders in which the relationship between anxiety states and depressive illnesses is examined. The question at issue is whether a line of demarcation may be drawn between the two disorders or whether they are more appropriately regarded as merging insensibly along a continuum of affective disturbance.

The prognosis of affective disorders: the differentiation of anxiety states from depressive illnesses

That a distinction may be made on clinical grounds between anxiety states and depressive illnesses has been affirmed by some authors (Garmany, 1956, 1958; Stenbäck, 1963), and rejected by others (Mapother, 1926; Conrad, 1958; Ey, 1963; Lewis, 1950–1966). This problem is also of interest from a biological point of view in that anxiety neuroses represent in an exaggerated form an emotion that is ‘directly serviceable’ (Cannon, 1928) and one which has potential survival value for the organism. Moreover, analogous conditions can be reproduced experimentally in animals, while no convincing models have so far been described of states akin to depressive illnesses (McKinney and Bunney, 1969).

The assessment and prediction of outcome in affective disorders

While detailed and systematic studies have been carried out on the course and outcome of manic-depressive psychoses (Kraepelin, 1921; Rennie, 1942; Poort, 1945; Lundquist, 1945; Astrup et al., 1959; Olsen, 1961; Bratfos and Haug, 1968), depressive illnesses (Lewis, 1936; Kay et al, 1969) and anxiety states (Miles et al., 1951; Eitinger, 1955; Greer and Cawley, 1966), there is little information concerning the prognosis of affective disorders as a whole.

Studies in the classification of affective disorders. The relationship between anxiety states and depressive illnesses. I

Disorders in which anxiety or depression is the predominant feature constitute a large part of contemporary psychiatric practice. They are also being increasingly recognized as the underlying causes of many conditions in general medicine and family practice for which, even after prolonged investigation, no physical basis can be discovered.

The relationship between the Maudsley Personality Inventory and the course of affective disorders

The Maudsley Personality Inventory (Eysenck, 1959a) measures the two factors of neuroticism and extraversion, which are considered to be independent and relatively stable aspects of personality in normal subjects. Bartholomew and Marley (1959) tentatively concluded that changes in the mental state did not greatly affect the N and E scores, and Mezey et al. (1963) found that the scores re mained relatively constant during depressive illness, although there was a slight increase in neuroticism. McGuire et al. (1963) noted that the relationship between N and E scores ceased to be orthogonal during illness when the scores became negatively correlated. Knowles (1960) found relatively high test-retest correlations in both a normal group and a neurotic group after a year, although the correlations in the neurotic group were lower than in the normal group; he also found some evidence that fluctuations in clinical state influenced the stability of the N scores. Moreover, on measuring neuroticism and extraversion with the Eysenck Personality Inventory (Eysenck and Eysenck, 1964), Knowles and Kreitman (1965) concluded that N (but not E) scores were influenced to a small but significant degree by changes in the patients' clinical state. Coppen and Metcalfe (1965) found that the mean N score of a group of depressed patients decreased significantly on recovery and that there was an associated significant increase in the mean E score. These changes were most marked in patients with endogenous depression. The scores of the recovered patients were within normal limits. Ingham (1966) demonstrated essentially similar changes over a three year period in a group of neurotic patients.

he relationship between premature death and affective disorders

The relationship between mental illness and physical disease in elderly patients has been the subject of a number of studies, notably those by Kay and Roth (1955) and Roth and Kay (1956). Stenstedt (1952, 1959) reported a high mortality rate among patients with manic-depressive psychosis and involutional melancholia, which he attributed to ‘the high frequency of suicide and to the fact that several patients had died in a mental hospital’. In a survey of elderly people living in the community, Kay and Bergmann (1966) demonstrated a relationship between physical illness and diminished life expectancy on the one hand and functional psychiatric disorders on the other. Shepherd et al. (1964), in a general practice survey in London, found a 'strongly marked association between psychiatric disorder and chronic organic illness'.

Some differences between published norms and data from matched controls as a basis for comparison with psychiatrically-disturbed groups

Over the years 1959 to 1962 a study was made of a series of 72 male neurotic patients referred to general hospital and private psychiatric practice in Leeds, the results of which were submitted for an M.D. Thesis (Little, 1966). It emerged clearly that the neurotic group was divisible into two major sub-groups differing significantly in a wide range of personality and other premorbid variables. Various objective tests and measurements were used; in the present context we wish to concentrate attention on five: (1 and 2) The N and E Scales of Eysenck's Maudsley Personality Inventory, (3) Tanner's Discriminant Androgyny Scale, (4) Parnell's Ponderal Index, and (5) The Rees-Eysenck Body Index.