Implications of impulsive and affective symptoms for serotonin function in bulimia nervosa

BACKGROUND

Bulimic, impulsive and depressive syndromes have all been associated with abnormalities in brain serotonin (5-hydroxytryptamine; 5-HT) mechanisms.

METHODS

We had 26 bulimic women and 22 normal-eater women report impulsive, affective, self-destructive and bulimic symptoms, and then provide serial blood samples for measurement of: [3H]-paroxetine binding in platelets; and, prolactin (PRL) responses following oral meta-chlorophenylpiperazine (m-CPP).

RESULTS

Bulimic status was associated with markedly reduced density of paroxetine-binding sites, modest blunting of m-CPP stimulated PRL response, and greater nausea following m-CPP. Biological variables did not co-vary with most psychopathological or eating-symptom indices. However, there were inverse associations (in bulimic women only) between scores indicating impulsivity (largely 'unreflectiveness') and density of platelet 5-HT uptake sites.

CONCLUSIONS

Our observations link bulimia nervosa to altered 5-HT functioning, and suggest that there may be a relatively symptom-specific association between impulsivity and reduced 5-HT reuptake.

Alzheimer's disease may not be a spirochetosis

It has been reported previously that spirochetes could be one of the causes of Alzheimer's disease (AD). In this study, we have attempted to reproduce these findings by examining fresh blood samples from 22 patients diagnosed with early stage (n = 16) and late stage (n = 6) AD. The patients were participants in a clinical drug trial. Fresh necropsy brain cortical specimens from AD patients (n = 7) were also examined. Spirochetes were observed microscopically in the blood of only one late-stage AD patient. None of the brain tissues showed the presence of spirochetes. Our results suggest that spirochetes are probably not associated with AD.

The dexamethasone suppression test and treatment outcome in elderly depressed patients participating in a placebo-controlled multicenter trial involving moclobemide and nortriptyline

The dexamethasone suppression test (DST) was conducted in 95 elderly DSM-III-R depressed patients randomized for treatment with moclobemide (MOC; 400 mg daily), nortriptyline (NT; 75 mg daily), or placebo (PBO) in a 7-week double-blind multicenter study. Patients were assessed weekly using various clinical scales, including the 17-item Hamilton Depression Rating Scale. The DST was administered at baseline and at the end of treatment. At baseline, no relationship was found between DST status and the various clinical scales used. At the end of treatment, suppressors (DST-) had significantly improved clinical ratings compared to nonsuppressors (DST+), and were mostly found among those treated with NT (71%) as compared to MOC (41%) or PBO (33%) (p < .03). On the other hand, baseline DST measures influenced treatment outcome; DST+ patients had a greater number of treatment responders to NT (48%) than MOC (19%) or PBO (20%) (p < .07). For DST- patients, the situation was reversed: NT, 7%; MOC, 31%. Postdexamethasone cortisol levels were lower in MOC responders (p < .07). An interaction was found between DST and drug-specific response. The DST may be a useful adjunct for predicting and evaluating the outcome of antidepressant therapy.

Cardiovascular, neuroendocrine, and monoaminergic responses to psychological stressors: possible differences between remitted panic disorder patients and healthy controls

Both clinical symptomatology and stress research suggest that panic attacks might be partially attributable to exaggerated psychophysiological responses to environmental stressors. In the present study, we aimed to explicitly test this idea by measuring the physiological responses to a mild psychological stressor in both healthy controls (n = 8) and fully remitted, medication-free panic disorder patients (n = 8). One hour before the stressor, former patients, compared to healthy controls, exhibited higher diastolic blood pressure. From a blood sample taken 30 min before the stressor, patients, compared to controls, had lower paroxetine platelet binding site densities. During the stressor, patients, compared to controls, had greater increases in plasma levels of cortisol. These preliminary findings suggest that remitted panic disorder patients might have disturbed physiological responses to mild psychological stressors. These disturbances might be related to the development of future episodes.

Clinical relevance of serum nortriptyline and 10-hydroxy-nortriptyline measurements in the depressed elderly: a multicenter pharmacokinetic and pharmacodynamic study

In a recent placebo-controlled multicenter study, 38 patients, ranging in age between 62 and 88 years (median, 71) were treated with nortriptyline (NT) for up to 7 weeks. NT was administered in a divided dose of 75 mg daily and serum NT (se NT), and its 10-hydroxy-metabolites (se OH-NT) were determined at various intervals. Several clinical measures of efficacy, including the 17-item Hamilton Rating Scale for Depression, were evaluated weekly as well as side effects (anticholinergic) and electrocardiogram (ECG) changes. Eighty-one percent of patients had NT levels in the previously defined therapeutic range of 50 to 170 ng/ml, with steady state reached between 1 and 3 weeks. There was little individual variation in drug kinetics and metabolism over the study period. In general se OH-NT levels were not greater than those of se NT. Pharmacodynamic analyses showed that patients with moderate to severe anticholinergic side effects [CSE(+)] had significantly higher NT levels than those with mild or no symptoms [CSE(-)]. Furthermore, repeated-measures ANOVA modeled over time showed a highly significant decrease in clinical measures in both CSE groups of patients and also a highly significant group-time interaction. Higher se OH-NT levels were associated with less anticholinergic side effects. No ECG changes were observed.

Reversible and selective inhibitors of monoamine oxidase A in the treatment of depressed elderly patients

The treatment of depression in the elderly population needs a thorough and careful work-up and an aggressive therapeutic approach. Any treatment initiative in this population often becomes difficult because of accompanying physical illness, concomitant medication, possible degenerative changes in central nervous system and age-related altered metabolic status. Despite unevenness in research findings, pharmacological treatment remains the mainstay of management of depression among elderly people. Currently available antidepressants, although effective, are problematic because of the increased vulnerability of the elderly to side effects. Recent research efforts to improve the efficacy and safety of drug treatment of depression resulted in development of reversible and selective monoamine oxidase inhibitors of the isoenzyme A (RIMA), with antidepressant efficacy comparable to tricyclic antidepressants and newer generation antidepressants. RIMAs include moclobemide, brofaromine, toloxatone and cimoxatone. Moclobemide is the most investigated available RIMA for therapeutic use at present. Its absorption and disposition in elderly individuals do not differ significantly from those in young healthy volunteers and depressed patients. The results of present clinical studies show that, in elderly depressed patients, moclobemide is at least as effective as other antidepressants. Its particular advantage is, however, that it is as well tolerated in elderly people as in younger people. There are only few significant adverse events, and they are generally less frequent and less severe than those with TCAs. An additional attribute of moclobemide seems also to be its beneficial effect on cognitive functions.

Prolonged penile erections induced by hydroxyzine: possible mechanism of action

We describe a subject who developed prolonged penile erections on hydroxyzine. Molecular modelling showed that the hydroxyzine metabolite, norchlorcyclizine, has structural and conformational similarities to the trazodone metabolite, m-chlorophenylpiperazine. This suggests that a common pharmacological mechanism may underlie the ability of trazodone and hydroxyzine to induce erections.

Biochemistry and pharmacology of reversible inhibitors of MAO-A agents: focus on moclobemide

Moclobemide, p-chloro-N-[morpholinoethyl]benzamide, is a prototype of RIMA (reversible inhibitor of MAO-A) agents. The compound possesses antidepressant efficacy that is comparable to that of tricyclic and polycyclic antidepressants. In humans, moclobemide is rapidly absorbed after a single oral administration and maximum concentration in plasma is reached within an hour. It is moderately to markedly bound to plasma proteins. MAO-A inhibition rises to 80% within two hours; the duration of MAO inhibition is usually between eight and ten hours. The activity of MAO is completely reestablished within 24 hours of the last dose, so that a quick switch to another antidepressant can be safely undertaken if clinical circumstances demand. RIMAs are potent inhibitors of MAO-A in the brain; they increase the free cytosolic concentrations of norepinephrine, serotonin and dopamine in neuronal cells and in synaptic vesicles. Extracellular concentrations of these monoamines also increase. In the case of moclobemide, increase in the level of serotonin is the most pronounced. Moclobemide administration also leads to increased monoamine receptor stimulation, reversal of reserpine induced behavioral effects, selective depression of REM sleep, down regulation of beta-adrenoceptors and increases in plasma prolactin and growth hormone levels. It reduces scopolamine-induced performance decrement and alcohol induced performance deficit which suggest a neuroprotective role. Tyramine potentiation with moclobemide and most other RIMA agents is negligible.

Comparison of the urinary glycoconjugates excreted by patients with type I and type II fucosidosis

Glycoconjugates were isolated, by repeated chromatography on Biogel P-4, from urine of two patients with different phenotypes of fucosidosis, type I (acute) and type II (chronic). Studies of the isolated compounds with thin-layer chromatography, chromatography on Biogel P-4, gas-liquid chromatography, and 1H- and 13C-nuclear magnetic resonance spectroscopy showed differences in the excretion patterns of fucosyl glycoconjugates in the urine of these patients. The amount of the diglycosylasparagine, fuc alpha 1-6glcNAc-Asn, excreted was significantly lower for the type I than for the type II patient. On the other hand, the reducing hexasaccharide gal beta 1-4(fuc alpha 1-3)glcNAc beta 1-2man alpha 1-3/6man beta 1-4glcNAc was present in much greater quantities in urine from the type I patient. The differences in the excretion patterns of these glycoconjugates may be attributed to different substrate specificities for the residual alpha-L-fucosidases in the two forms of the disease. I propose that such differences may be exploited for the early laboratory diagnosis of the type II form of the disease, particularly by thin-layer chromatography.

Comparison of the urinary glycoconjugates excreted by patients with type I and type II fucosidosis

Glycoconjugates were isolated, by repeated chromatography on Biogel P-4, from urine of two patients with different phenotypes of fucosidosis, type I (acute) and type II (chronic). Studies of the isolated compounds with thin-layer chromatography, chromatography on Biogel P-4, gas-liquid chromatography, and 1H- and 13C-nuclear magnetic resonance spectroscopy showed differences in the excretion patterns of fucosyl glycoconjugates in the urine of these patients. The amount of the diglycosylasparagine, fuc alpha 1-6glcNAc-Asn, excreted was significantly lower for the type I than for the type II patient. On the other hand, the reducing hexasaccharide gal beta 1-4(fuc alpha 1-3)glcNAc beta 1-2man alpha 1-3/6man beta 1-4glcNAc was present in much greater quantities in urine from the type I patient. The differences in the excretion patterns of these glycoconjugates may be attributed to different substrate specificities for the residual alpha-L-fucosidases in the two forms of the disease. I propose that such differences may be exploited for the early laboratory diagnosis of the type II form of the disease, particularly by thin-layer chromatography.

Hexosaminidase-A deficiency presenting as atypical juvenile-onset spinal muscular atrophy

Three patients from two families had an unusual phenotypical variant of late-onset hexosaminidase-A deficiency. The clinical picture was dominated by spinal motor neuron involvement mimicking juvenile-onset spinal muscular atrophy. Atypical features included prominent muscle cramps, postural and action tremor, recurrent psychosis, incoordination, corticospinal and corticobulbar involvement, and dysarthria. The presence of these atypical features in patients whose lower motor neuron involvement would otherwise be consistent with juvenile-onset spinal muscular atrophy should raise the suspicion of the presence of hexosaminidase-A deficiency and GM2 gangliosidosis that can be proved by appropriate enzyme assays.

Identification of retinoyl complexes as the autofluorescent component of the neuronal storage material in Batten disease

Cytosomes filled with intensely fluorescent material in the form of curvilinear bodies were isolated by density gradient centrifugation followed by pronase digestion from the cerebral cortex of a child who had died at age 7 from the late infantile form of Batten disease. Forty-three percent of the dry weight of the storage material was extracted by a mixture of chloroform and methanol, leaving a waterinsoluble amorphous fluorescent residue. Infrared spectroscopy, proton magnetic resonance spectrscopy, and mass spectrometry of this residue strongly suggested the presence of retinoyl polyenes linked to a small peptide. Base hydrolysis and methanolysis yielded retinoic acid and methyl retinoate, respectively. Ozonolysis yielded a product derived from the substituted cyclohexenyl ring of vitamin A. The results indicate that the fluorescent component of the neuronal storage material is a retinoyl complex and is not derived from peroxidized polyunsatured fatty acids as previously thought.