Recent trends and clinical features of childhood vitamin D deficiency presenting to a children's hospital in Glasgow

BACKGROUND

The incidence of vitamin D deficiency is unclear in the context of continuing demographic changes and the introduction of new public health measures.

METHODS

All cases in which vitamin D deficiency was suspected as the primary cause of the clinical presentation were studied.

RESULTS

Between 2002 and 2008, 160 cases of symptomatic vitamin D deficiency were identified with twice as many cases in 2008 (n, 42) as in the previous years. The median age of the cohort was 24 months (range 2 weeks-14 years).Three cases were recorded in children of European background, whereas the rest were in children of South Asian, Middle Eastern or sub-Saharan ethnic background. Presenting features included bowed legs in 64 (40%) and a fit in 19 (12%). In one infant, concerns were raised following a presentation with cardiac failure and hypocalcaemia.

SUMMARY

Symptomatic vitamin D deficiency remains prevalent in the West of Scotland. There is a need for effective public health education, action and surveillance.

Some effects of melatonin and the control of its secretion in humans

Whether or not the pineal gland has a significant physiological role in humans is not known. There has nevertheless been speculation about the potential therapeutic use of melatonin (in view of its hypnotic and possible zeitgeber properties) in conditions such as insomnia and jet lag, and in shift-workers. Our work concerns the effects of melatonin administration in humans and the interactions between melatonin and other circadian variables. Chronic (one month), timed (1700 h), low-dose (2 mg daily) melatonin administration to normal subjects without environmental control consistently increased evening fatigue and slightly modified the 24 h prolactin rhythm without effect on cortisol, growth hormone, luteinizing hormone, thyroxine, testosterone or self-rated mood. In five out of 11 subjects the endogenous melatonin rhythm was advanced by one to three hours. During fractional desynchronization of circadian rhythms by increasing imposed 'day' length (26-29 h, 24 days, 500 lux), 5 mg melatonin per os at lights-out in two subjects resulted in better entrainment of the fatigue rhythm to the zeitgeber than in five out of six control subjects, without major consistent effects on other measured circadian variables. Using a new radioimmunoassay for 6-hydroxymelatonin sulphate (aMT6s), the major melatonin metabolite, we have shown that the urinary aMT6s rhythm is closely correlated to that of melatonin in plasma and is completely suppressed by an acute dose of atenolol (100 mg per os), a peripheral beta-adrenergic antagonist. During fractional desynchronization by increasing imposed 'day' length in one subject and decreasing imposed 'day' length in two subjects, the urinary aMT6s rhythm behaved similarly to that of core temperature. The results suggest that fatigue (or alertness) may be entrained by melatonin, but whether critical performance rhythms can be suitably manipulated remains to be clarified. It is likely that melatonin production is linked to the so-called 'strong' circadian oscillator.

Neuroendocrine and other studies of the mechanism of antidepressant action of desipramine

It is not known whether in depressed patients antidepressant treatment increases or reduces monoaminergic neurotransmission. Clinical studies are therefore reviewed that investigate adaptive changes at adrenoceptors in depressed patients treated with desipramine, and the net effect of these changes upon neurotransmission. Although in animals chronic desipramine treatment enhances the responsiveness of alpha 1-adrenoceptors to phenylephrine, no such effect could be demonstrated in patients upon the responsiveness of pupil diameter to phenylephrine. However, in keeping with animal studies, clinical evidence of altered responsiveness of alpha 2-adrenoceptors could be demonstrated after chronic desipramine treatment. The alpha 2-mediated growth hormone response to clonidine was increased after one week's treatment with desipramine and then reduced during the second and third weeks of treatment. No clinical measure of the responsiveness of central beta-adrenoceptors is available. However, the secretion of melatonin is a measure of neurotransmission at noradrenergic terminals in the pineal with alpha 1-, alpha 2- and beta 1-adrenoceptors. In normal volunteers the secretion of melatonin was increased by the noradrenaline uptake inhibitors desipramine and (+)-oxaprotiline; (-)-oxaprotiline had no effect. In depressed patients melatonin secretion was increased after three weeks' treatment with desipramine. These and other clinical studies suggest that antidepressant treatments increase noradrenergic neurotransmission in depressed patients.

Further ethical and social issues in using a cocaine vaccine: response to Hall and Carter

Evaluation of the potential of a cocaine vaccine requires a detailed understanding of the intended and unintended social consequences of its use. Prospective technology assessment is always difficult, but in the case of treatment and prevention of cocaine addiction we need to understand not only the neuroscience and pharmacology of cocaine addiction, but also social attitudes to drug use and addiction, the social context of drug use, and the factors which make drug use a rational strategy for an addict and make treatment seeking or relapse more or less likely. By considering different scenarios related to differing levels of effectiveness of the vaccine, the authors argue that vaccination will be at best a useful adjunct to existing methods of treatment, rather than a substitute for them.

Addicts' drug-related dreams: their frequency and relationship to six-month outcomes

101 drug users were interviewed at baseline when 6-weeks abstinent. Eighty-four percent reported having drug-related dreams. More subjects reported drug dreams when abstinent than when using drugs. Ninety percent of subjects were followed-up at 6 months. Higher baseline measures of dream frequency were prospectively related to greater drug use. In the first 7 weeks of follow-up there was a rapid reduction in the number of reports, but half of the sample were still experiencing drug dreams in the sixth month. Drug dream frequency at follow-up was related to "craving" and lack of sleep.

Drug users' spiritual beliefs, locus of control and the disease concept in relation to Narcotics Anonymous attendance and six-month outcomes

Narcotics Anonymous (NA) is an important support network for drug users emerging from abstinence based treatments. However, the views of NA on 'spirituality' and the 'disease' nature of addiction could be seen as encouraging an external attributional style and have been cited as reasons for non-attendance. After 6 months ninety percent of 101 drug users in treatment were followed up. Narcotics Anonymous attendance was inversely related to drug use for those who had left residential care. We found that spiritual beliefs and disease concept beliefs were not prerequisites for attendance of NA. Spiritual beliefs were not found to cause external attributions for previous drug use or possible future lapse events. It emerged that the most powerful predictors of non-attendance were positive attitudes to the use of alcohol. Treatment implications are discussed.

Treatment and services for drug users in Britain

The pattern of British drug service provision was transformed during the late 1980s. Policy makers and service providers recognised the need for a more flexible response to changing drug trends and client needs; consequently community-based services proliferated. HIV has had considerable impact on the working approach of many agencies, where harm minimisation is now the immediate goal. This article provides an overview of patterns of drug use and drug service provision in Britain.

Melatonin rhythms in seasonal affective disorder

We examined 24-hour melatonin rhythms from 20 patients with seasonal affective disorder (SAD) and 20 healthy volunteers. Patients and controls were individually matched for age, sex, and month of study. Plasma samples were taken at hourly intervals, and were assayed for melatonin by radio-immunoassay. The 24-hourly melatonin estimations for each individual were fitted to a cosine curve, and the significance of the curve fits was calculated. Two analyses were performed. In analysis 1 the following were calculated: (a) cosine fit, (b) significance of fits, (c) mean amplitude and acrophase (peak) and (d) mean melatonin levels. The curve fits were highly significant for all but three subjects (two patients, one control), but there were no significant differences in any measure between the two groups. In analysis 2 the comparisons were repeated and restricted to the 18 patients and 19 controls in whom there was a significantly significant melatonin rhythm. Again there were no significant differences between groups. These results suggest that the circadian rhythm of melatonin is not abnormal in SAD, and that the therapeutic effect of light in SAD is not mediated by phase shifts in melatonin secretion.

Plasma melatonin levels in anorexia nervosa

Plasma melatonin levels were measured at three-hourly intervals over 24 hours in 11 women with untreated anorexia nervosa, and in nine healthy women of normal weight. The circadian rhythm was unaltered but the nocturnal secretion of melatonin was significantly greater in anorectics. It is possible that this was related to nocturnal hypoglycaemia.

A study of the effects of desipramine treatment alone and in combination with L-triiodothyronine on 6-sulphatoxymelatonin excretion in depressed patients

Urinary 6-sulphatoxymelatonin (alpha MT6s) excretion was measured after one day and one, two and three weeks of desipramine treatment in eight depressed patients. There was significant increase in the urinary excretion of alpha MT6s after one week of treatment, and at no time was there any decrease in alpha MT6s excretion. These findings are opposed to the hypothesis that desipramine reduces noradrenergic neurotransmission in the human pineal. In a further five patients whose depression was resistant to desipramine alone, urinary alpha MT6s excretion was measured during treatment with adjunctive L-triiodothyronine (T3). There was no change in alpha MT6s excretion, and thus the previously reported potentiation of the efficacy of tricyclic antidepressants in combination with T3 does not appear to be mediated through an alteration in noradrenergic neurotransmission.

Effects of light treatment upon mood and melatonin in patients with seasonal affective disorder

Ten patients with seasonal affective disorder received the following treatments for 5 days each: (a) artificial daylight (2500 lux) from 20.00 to 23.00 and from 07.00 to 10.00 hours; (b) red light (300 lux) from 20.00 to 23.00 and from 07.00 to 10.00 hours; (c) artificial daylight (2500 lux) from 22.00 to 23.00 and from 07.00 to 08.00 hours. The antidepressant effect of treatment (a) was superior to that of treatment (b), suggesting that the effect of light treatment in winter depression is more than that of a placebo. The antidepressant effect of treatment (a) was superior to that of treatment (c), although these two treatments equally suppressed plasma melatonin concentrations. Consequently, in these patients there is a dissociation between the effect of light treatment on melatonin and the reduction of depression ratings.

Evidence for a functional role of alpha-1 adrenoceptors in the regulation of melatonin secretion in man

Nocturnal plasma melatonin concentrations were reduced following administration of the alpha 1 adrenoceptor antagonist, prazosin (2 mg orally at 1900h), to 10 normal men. These data indicate that alpha 1 adrenoceptors are involved in the physiological control of melatonin secretion in man.

A study of sulphatoxymelatonin excretion and gonadotrophin status during weight gain in anorexia nervosa

To clarify a controversy as to whether melatonin secretion is related to body weight, urinary sulphatoxymelatonin (aMT6s) excretion was estimated in 10 patients with anorexia nervosa before and after weight gain, and compared with 10 age-matched controls. There was no change in aMT6s excretion after weight gain, and no significant difference between the patients and control groups at either point. Significant increases in plasma LH, FSH, and estradiol were detected after weight gain in anorexic patients, independent of aMT6s excretion.

A comparison of melatonin secretion in depressed patients and normal subjects

Depressed patients were carefully matched in pairs with normal subjects for the variables which are known to influence the secretion of melatonin in humans. In contrast to the previous literature, nocturnal melatonin secretion was not lower in the depressed group than in the normal group, and there was no difference in the timing of secretion; indeed, the trend was for greater melatonin secretion in the depressed group. The results are discussed in relation to previous studies, none of which has been so carefully controlled for the relevant variables.

Suppression of nocturnal plasma melatonin and 6-sulphatoxymelatonin by bright and dim light in man

Previous studies have shown that bright light (2500 lux) suppresses nocturnal secretion of melatonin, while dim light (500 lux) has little or no effect. We have studied the effect of varying intensities of light on 5 normal male volunteers (age 18-28). The experiment was divided into 3 parts which took place at weekly intervals. Subjects remained under artificial light (fluorescent strip 150-250 lux) between 2000 h-2300 h, they then retired to bed in darkness. On each occasion, between 0030 h and 0100 h, the subjects were required to get up and were treated with light of different intensities; (a) less than 1 lux, (b) 300 lux and (c) 2500 lux respectively. Subjects returned to bed in darkness until 0700 h. Blood was sampled hourly from 2000 h-1000 h with additional samples at 2330 h, 0015 h, 0030 h, 0045 h, 0115 h and 0130 h. Plasma melatonin and 6-sulphatoxymelatonin (aMT6s), the major melatonin metabolite, were measured by radioimmunoassay. Dim (300 lux) and bright (2500 lux) light, both significantly suppressed melatonin levels compared to less than 1 lux (P less than 0.05 and P less than 0.01 respectively) at the following time points 0100 h, 0115 h and 0130 h. One subject did not show suppression with 300 lux. There was also a significant suppression of aMT6s levels, compared to less than 1 lux, after both 300 lux and 2500 lux at 0115 h (P less than 0.05, P less than 0.01), 0130 h (P less than 0.01, P less than 0.01) and 0200 h (P less than 0.01, P less than 0.001) respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Suppression of nocturnal plasma melatonin and 6-sulphatoxymelatonin by bright and dim light in man

Previous studies have shown that bright light (2500 lux) suppresses nocturnal secretion of melatonin, while dim light (500 lux) has little or no effect. We have studied the effect of varying intensities of light on 5 normal male volunteers (age 18-28). The experiment was divided into 3 parts which took place at weekly intervals. Subjects remained under artificial light (fluorescent strip 150-250 lux) between 2000 h-2300 h, they then retired to bed in darkness. On each occasion, between 0030 h and 0100 h, the subjects were required to get up and were treated with light of different intensities; (a) less than 1 lux, (b) 300 lux and (c) 2500 lux respectively. Subjects returned to bed in darkness until 0700 h. Blood was sampled hourly from 2000 h-1000 h with additional samples at 2330 h, 0015 h, 0030 h, 0045 h, 0115 h and 0130 h. Plasma melatonin and 6-sulphatoxymelatonin (aMT6s), the major melatonin metabolite, were measured by radioimmunoassay. Dim (300 lux) and bright (2500 lux) light, both significantly suppressed melatonin levels compared to less than 1 lux (P less than 0.05 and P less than 0.01 respectively) at the following time points 0100 h, 0115 h and 0130 h. One subject did not show suppression with 300 lux. There was also a significant suppression of aMT6s levels, compared to less than 1 lux, after both 300 lux and 2500 lux at 0115 h (P less than 0.05, P less than 0.01), 0130 h (P less than 0.01, P less than 0.01) and 0200 h (P less than 0.01, P less than 0.001) respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of a phosphodiesterase inhibitor (Rolipram) on the urinary excretion of 6-sulphatoxy melatonin in man

The urinary excretion of 6-sulphatoxymelatonin (aMT6s) from 2400 to 0600 h was significantly increased following the treatment of ten normal volunteers with a phospho diesterase inhibitor (rolipram 1 mg 8 h for 24 h). The urinary excretion of the metabolite from 0600 to 1200 h was significantly reduced after treatment with rolipram.

Acute treatment with desipramine stimulates melatonin and 6-sulphatoxy melatonin production in man

Acute administration of the antidepressant drug desipramine (DMI) in man, increased evening melatonin secretion, which reached peak plasma levels 2-4 h earlier than after placebo administration. The increase at set time points 21.00 h-22.00 h was directly proportional to an individual's integrated night-time secretion of melatonin. We have shown that this stimulation was not an effect of DMI inhibition on the hepatic metabolism of melatonin to 6-sulphatoxy melatonin (aMT6s), indeed aMT6s is in itself a good index of the evening melatonin rise. The stimulation of early evening melatonin by DMI might be exploited as a simple pineal function test.

The effects of exogenous melatonin on endocrine function in man

At two different times of year (spring and autumn) an oral preparation of the pineal neurohormone melatonin, or placebo, was administered to 12 healthy volunteers (10 men and two women in spring: the same group minus one man in autumn) daily at 1700 h for 1 month (spring), or 3 weeks (autumn) using a double-blind cross-over protocol. The daily dose was 2 mg melatonin in 5 ml corn-oil, and placebo consisted of the vehicle only. In spring the anterior pituitary hormones LH, PRL, GH together with T4, cortisol, testosterone and melatonin were measured at 1- to 6-h intervals for 24 h in plasma on the day following the last dose. In autumn PRL, cortisol and melatonin levels were measured on the last day of treatment. Subjective fatigue, mood and sleep records were kept throughout the studies. Melatonin increased early evening fatigue and actual sleep, but had no effect on mood: these results are reported in full elsewhere. Melatonin administration had no effect on the levels or 24-h rhythm of LH, GH, T4, testosterone or cortisol. An earlier fall in the nocturnal PRL was observed on both occasions. Overall PRL levels were higher in spring than in autumn. In five of the subjects, the secretion of endogenous melatonin was advanced by 1-3 h in the presence of exogenous melatonin. These observations suggest that the potential therapeutic use of melatonin as a hypnotic or in the treatment of jet lag is unlikely to be complicated by undesirable endocrine effects.

The effect of desipramine upon melatonin and cortisol secretion in depressed and normal subjects

Melatonin and cortisol values in plasma were measured hourly over 24 hours in six depressed patients and six normal volunteers before treatment and after one and three weeks of treatment with desipramine. The normal volunteers were further tested one week after withdrawal of desipramine. The mydriatic effects of tyramine and phenylephrine eye drops were also recorded in the normal volunteers. In neither group of subjects did desipramine treatment reduce melatonin secretion, suggesting that functionally significant down-regulation of beta andrenoceptors was not caused by this treatment. Melatonin secretion was significantly increased after three weeks of treatment in depressed patients. This increase was not found in normal subjects.

Immunoassay of 6-hydroxymelatonin sulfate in human plasma and urine: abolition of the urinary 24-hour rhythm with atenolol

An assessment of the rhythmic characteristics of melatonin secretion in man and other species requires the determination of 24-h secretion profiles. Measurement of a major excreted metabolite would allow noninvasive study of pineal function, applicable in particular to pediatric and long term circadian rhythm studies. This report describes a simple and rapid RIA for 6-hydroxymelatonin sulfate in human plasma and urine. Physiological studies revealed that both plasma and urinary levels of 6-hydroxymelatonin sulfate were closely related to plasma melatonin, and that the urinary 24-h rhythm was abolished by the beta 1-adrenergic anagonist atenolol.

Plasma concentrations of melatonin in man following oral absorption of different preparations

The plasma concentrations of melatonin in man, fasting and fed, were determined after ingestion of three different oral preparations. A dose of 2 mg was given as either a gelatine capsule, a solution in corn oil or as a slow-release pill. Gelatine capsules and the corn oil preparation gave reproducibly timed peak plasma concentrations, 30 to 60 min after ingestion regardless of nutritional status, and plasma melatonin remained at or above endogenous night-time levels for 3-4 h with mean elimination half-lives of 0.54 to 0.67 h. The slow-release preparation usefully extended high plasma melatonin concentrations for 5-7 h after ingestion but the timing of peak concentrations was very dependent on nutritional status. These preparations should be of use in the study of timed melatonin administration in man.

Clinical studies of the effect of (+) and (-)-oxaprotiline upon noradrenaline uptake

In six normal male subjects the mydriatic effect of tyramine eye drops was inhibited by 1 day's treatment with desipramine and the (+)- but not the (-)-enantiomer of oxaprotiline. In the same experiment, the secretion of melatonin was increased after treatment with (+)- but not with (-)-oxaprotiline. The effects of (+)-oxaprotiline and of desipramine treatment were similar, as were those of (-)-oxaprotiline and placebo. These findings extend to clinical studies the demonstration in animal experiments of stereo-specificity for the effects of (+)- and (-)-oxaprotiline upon noradrenaline uptake. A comparison of the effects of the two enantiomers should provide an ideal strategy for studying effects of noradrenaline uptake blockade in clinical studies.

The effects of chronic, small doses of melatonin given in the late afternoon on fatigue in man: a preliminary study

In a double-blind cross-over study, melatonin (2 mg) or placebo, was administered daily for 4 weeks to 12 volunteers (10 men and 2 women) at 17.00 h during February and March. Self-rated fatigue (tiredness) was significantly increased in the evening during melatonin treatment. No other consistent effects on sleep ratings or mood parameters were observed and the dose was well tolerated.