Lolke Pepplinkhuizen

Incidence of and preoperative predictors for delirium after cardiac surgery

Incidence of and preoperative predictors for postoperative delirium were studied in 296 patients (age 26-83 years, mean age 63 years) undergoing elective cardiac surgery. Delirium occurred in 40 (13.5%) patients. Predictors included old age, low level of albumin, poor physical condition, use of nifedipine, and a high ratio of the amino acids phenylalanine to the sum of isoleucine, leucine, valine, tyrosine, and tryptophan. These findings suggest that preoperative physical condition and amino acid disturbances may be related to delirium after cardiac surgery in the elderly.

Motor activity and autonomic cardiac functioning in major depressive disorder

BACKGROUND The daily pattern of motor activity and the autonomic cardiovascular regulation were studied in major depression to quantify changes in psychomotor function and autonomic cardiac functioning. Additionally, relationships between motor activity parameters, cardiovascular measures and specific clinical features were examined. METHODS Wrist-actigraphy was used to monitor 24-h motor activity for 67 unmedicated (unipolar) depressed inpatients and 64 control subjects. During supine rest, spectral analysis was applied to assess HR and SBP variability, a baroreflex sensitivity (BRS) index and the respiratory frequency, in addition to mean heart rate (HR) and blood pressure (BP) levels for the patient group and a second control group (N=51). RESULTS The patients showed a lower motor activity level and a reduced fragmentation of motor activity during wake, and a higher motor activity level and a decreased immobility during sleep. The mean HR and DBP level and the respiratory frequency were higher in the patient group than in the control group, but no differences in HR and SBP variability or BRS were found. Furthermore, motor activity parameters and cardiovascular measures of the patients were related to agitation and retardation and overall, patients with lower motor activity levels demonstrated lower SBP levels. CONCLUSIONS This study confirms that the 24-h pattern of motor activity is altered in unmedicated depressed inpatients, but limited evidence was found for an autonomic cardiac dysfunction. Within the patient group there were relationships between motor activity parameters, cardiovascular measures, and clinical features, but the underlying neurobiological pathways need to be further explored.

Cardiovascular variability in major depressive disorder and effects of imipramine or mirtazapine (Org 3770).

Spectral analysis of fluctuations in heart rate (HR) and blood pressure (BP) was applied to assess sympathetic and parasympathetic cardiovascular control mechanisms in patients with unipolar affective disorder before and after treatment with imipramine (IMI) or mirtazapine (MIR). In a double-blind randomized study, 10 patients received treatment with IMI and 10 patients received treatment with MIR. Cardiovascular parameters were studied before and after 4 weeks of treatment: HR and BP (Finapres) were recorded continuously during supine rest (SR) and orthostatic challenge (OC; 60-degrees head-up tilting). During SR and OC, power spectra were calculated for HR and systolic BP. Spectral density was assessed for three frequency bands: low (0.02-0.06 Hz), mid (0.07-0.14 Hz), and high (0.15-0.50 Hz). Before treatment, the depressed patients (N = 20) differed from age-matched controls (N = 20) only in their response to OC: the depressed patients showed more suppression of HR variability (both mid- and high-frequency band fluctuations), indicating stronger vagal inhibition, and a reduced increase of BP variability (mid-frequency band fluctuations), indicating reduced sympathetic activation. After 4 weeks of treatment, patients treated with either antidepressant drug showed significant changes of HR (increase) and HR variability (decrease) during SR and OC; the suppression of mid- and high-frequency fluctuations of HR was larger for IMI than for MIR. The increase in HR and decrease in HR variability may be attributed to the anticholinergic properties of IMI (strong) and MIR (weak), resulting in cardiac vagal inhibition. Whereas MIR had no effect on BP or BP variability, IMI specifically reduced mid-frequency band fluctuations of BP as the result of a suppression of central sympathetic activity. Our data confirm and extend previous observations on the presence of autonomic dysfunctions in unmedicated depressed patients: spectral analysis of HR and BP fluctuations suggested that both parasympathetic and sympathetic mechanisms are involved, specifically during OC. The preexisting autonomic cardiovascular dysfunctions were not normalized by antidepressant drugs. In fact, some of the components of the cardiovascular autonomic dysfunction were further aggravated, depending on the pharmacologic profile of the drug under investigation.

Seasonal Variations in Binding of 3H-Paroxetine to Blood Platelets in Healthy Volunteers: Indications for a Gender Difference

Binding of paroxetine to blood platelet membranes was studied longitudinally in 20 healthy volunteers (11 men and 9 women) in order to determine seasonal and gender variations. Blood samples were obtained in September, December, March, and June, and repeated in September. A significant seasonal variation in the maximal number of binding sites (Bmax) was found. Men were found to have significantly lower (Bmax) values than women. Although the pattern of seasonal variation was not identical in men and women, no significant differences were detected. The affinity constant (KD) of paroxetine binding showed a significant seasonal variation. Men were found to have a significantly higher KD (lower affinity) than women. The pattern of seasonal variation was identical in men and women. These data support the evidence indicating a substantial seasonal effect on the serotonergic system, and show that in paroxetine binding studies, groups of subjects should be matched for season and gender.

Effect of electroconvulsive therapy on biopterin and large neutral amino acids in severe, medication-resistant depression

Biopterin, neopterin and the large neutral amino acids (LNAA), i.e. phenylalanine, tyrosine, tryptophan, isoleucine, leucine and valine were measured in plasma of 20 severely depressed inpatients before and after a course of electroconvulsive therapy (ECT). These patients showed a significantly lower plasma biopterin concentration at baseline in comparison with healthy controls. After treatment an increase in biopterin was found, which was statistically significant in the depressed patients with psychotic features. The plasma phenylalanine-tyrosine ratio, which previously increased, normalised after ECT. Mean tryptophan concentration was lower in depressed patients than in normal controls. The patients who responded to ECT showed an increase in the tryptophan concentration and its ratio (tryptophan/LNAA) after treatment. Our results suggest that ECT increases biopterin, which probably results in synthesis of amino acids, especially tyrosine. Furthermore, ECT seems to increase cerebral tryptophan availability because of less tryptophan catabolism parallel with biopterin activation. More research is required to see if biopterin could be useful as a biological marker for the depressive state in this subgroup of patients, because this compound seems to play an important role in the etiology and treatment of depression.

Is postoperative delirium related to reduced plasma tryptophan

The cause of postoperative delirium is unknown. In 7 patients with postcardiotomy delirium (6 men, 1 woman; mean age 67 years), we observed a plasma concentration of tryptophan and a plasma tryptophan ratio significantly lower than in 8 non-delirious postoperative control patients. We suggest that the mental symptoms of postcardiotomy delirium are the consequence of a reduced cerebral tryptophan availability due to a catabolic state.

24-Hour motor activity after treatment with imipramine or fluvoxamine in major depressive disorder

Psychomotor dysfunction in depression is related to alterations in the 24-h pattern of motor activity. After antidepressant treatment the diurnal pattern may be changed due to improvement of clinical state or pharmacological actions. The purpose of this study was to evaluate in 52 depressed in-patients the effects of imipramine (tricyclic antidepressant) and fluvoxamine (SSRI) on the 24-h motor activity. Motor activity was monitored by wrist-actigraphy during a medication-free period and after 4 weeks of treatment. Clinical improvement was not different after imipramine or fluvoxamine treatment. The Hamilton depression score decreased in patients treated with imipramine, as well as in patients treated with fluvoxamine. The clinical retardation score was also reduced in both treatment groups. However, patients treated with imipramine showed higher motor activity levels during the wake period in comparison to the medication-free period, and more fragmentation of motor activity during sleep. Treatment with fluvoxamine did not result in alterations in the 24-h pattern of motor activity. The improvement of depressive mood and retardation seems to play a minor role in the change of the pattern of motor activity after imipramine.

Anxiety and autonomic regulation in major depressive disorder: an exploratory study

Spectral analysis of fluctuations in heart rate and blood pressure was employed to explore sympathetic and parasympathetic cardiovascular control mechanisms in relation to trait anxiety in major depressive disorder Sixteen drug-free female depressed patients were divided into two groups: those who were high on trait anxiety (HTA, n = 9) and those who were normal or low on trait anxiety (LTA, n = 7). In patients and age-matched female controls (n = 10), heart rate (HR), blood pressure (BP; Finapres device) and respiration were recorded during a period of supine rest (10 min), orthostatic challenge (60 degrees head-up tilting, 8 min), and post-orthostatic supine rest (8 min). Power spectra were calculated over the last 4 min of these three situations for HR, systolic BP, as well as for respiration. Spectral density was assessed for three frequency bands: low (0.02-0.06 Hz), mid (0.07-0.14 Hz) and high (0.15-0.50 Hz). Patients did not differ from controls during supine rest. During orthostatic challenge, HTA patients showed significantly more HR increase and suppression of high-frequency fluctuations of HR (suggesting stronger vagal inhibition) in comparison with the controls; this effect was accompanied by a significant increase in respiratory frequency. Both patients groups did not show the normal increase in mid-frequency band fluctuations of BP during orthostatic challenge, indicating reduced sympathetic activation. Low-frequency fluctuations of HR, as well as respiratory frequency during post-orthostatic supine rest of the HTA patients were significantly increased versus controls. This exploratory study indicates that trait anxiety may be a relevant factor when evaluating parasympathetic and sympathetic dysbalances in the state of a major depressive disorder.

SCHIZOPHRENIA-LIKE PSYCHOSIS CAUSED BY A METABOLIC DISORDER

Four patients with an intermittent psychosis closely resembling hallucinogenic drug-induced states were suspected of having a porphyric disease and were investigated for a possible relation between the metabolic dysfunctions of porphyria and the psychotic syndrome. Theoretically the link could be in a disturbance of serine and glycine metabolism. This theory was supported by disturbances in serine and glycine excretion found in all patients during psychotic episodes. In addition, loading with one low oral dose of serine produced psychotic symptoms 5 h later which lasted 3-6 h. One patient reacted to glycine in the same way. These findings suggest that disturbed serine-glycine metabolism may have a key role in certain schizophreniform psychotic syndromes.

Abnormal plasma levels of serine, methionine, and taurine in transient acute polymorphic psychosis

The present study explored the usefulness of plasma amino acid concentrations in discriminating a subgroup of patients with transient acute polymorphic psychoses characterized by psychosensory symptoms (APP+ patients). Levels of amino acids in the plasma of APP+ patients were compared with levels in psychiatric patients with other types of psychotic symptomatology and a healthy control group. Both the APP+ patients and patients with bipolar affective disorder had significantly lower plasma concentrations of serine compared with concentrations in the other groups studied. Since the plasma concentrations of taurine and methionine were also different in the APP+ patients, the ratio of taurine to the product of serine and methionine (the TSM ratio) was used in an attempt to increase the sensitivity in discriminating these patients. The TSM ratio in the APP+ patients was significantly higher than those in the other groups studied, except for the patients with bipolar affective disorder. It appears that the determination of serine and the TSM ratio in the plasma of psychotic patients may be a useful diagnostic validator in a group of patients with acute polymorphic psychoses.