Biomedical subjects

H van Praag

Publications and source records attributed to H van Praag.

26 records · Page 2Linked to original sources

PubMed1991

Desipramine treatment in panic disorder.

Apart from imipramine (IMI), the efficacy of tricyclic antidepressants in panic disorder (PD) has received surprisingly little investigation. The authors report on a 6 week open trial of desipramine (DMI) preceded by a 10 day placebo lead-in, in 15 patients with PD. By week 6, 80% of the patients were globally rated as much or very much improved on a mean dose of 198 mg. Much of the improvement resulted from a reduction in non-panic attack symptomatology (i.e., psychic, somatic and phobic anxiety). Longer duration of illness, male gender and residual psychic anxiety were associated with poorer response in a subgroup of patients. DMI caused minimal intolerable side effects, suggesting possible compliance advantages in comparison to IMI. Beyond supporting the efficacy of DMI in PD, the results of the study point to a significant medication responsive non-panic illness component and caution against over-relying on panic attacks in assessing both illness severity and treatment response.

Adult↗

PubMed1990

The role of glutamate in opiate descending inhibition of nociceptive spinal reflexes.

The present experiment examined descending inhibition of the nociceptive tail-flick reflex produced by microinjection of morphine and glutamate into the periaqueductal gray (PAG) matter and the neurotransmitters mediating the inhibition at the level of the nucleus raphe magnus (NRM). The longlasting opiate analgesia was significantly reduced by microinjection of excitatory amino acid antagonists 1-(p-chlorobenzoyl)-piperazine-2,3-dicarboxylate (PCB, 3.25 mumol) or DL-2-amino-5-phosphono-valerate (APV, 25.38 mumol) into the NRM, whereas the short-lived glutamate analgesia was not. This indicates that although both opiate and non-opiate analgesia may originate in the PAG, the former is relayed through the NRM, whereas the latter is relayed by additional or different nuclei in the medulla. Two observations shed light on the question which receptors mediate the above effect in the NRM. First, PCB blocked morphine analgesia at doses that were 8 times lower than doses of APV that were effective. Second, analgesia produced by injection of glutamate into the NRM was antagonized by PCB (3.25 mumol), whereas APV (25.38 mumol) failed to do so. Together these results indicate that kainate/quisqualate, but not N-methyl-D-aspartate (NMDA), receptors are implicated in the NRM as a relay station in opiate descending inhibition.

2-Amino-5-phosphonovalerate↗

PubMed1989

EEG asymmetries may be affected by cranial and brain parenchymal asymmetries.

The plagiocephaly index, an index that reflects an underlying anatomic asymmetry of the brain, was assessed in ten schizophrenic patients and its values were correlated with the lateral distribution of quantitatively evaluated EEG. The correlations between the index and alpha power at F7 were significant, positive for frontal asymmetry (frontal bulging) and negative for occipital flattening. We then studied ten normal subjects in an attempt to illuminate the contribution of several cephalic and cranial variables to the imbalance of alpha-afterdischarges (AD) of VEP recorded at O1-O2. The asymmetry index of AD was computed and correlated with asymmetries of CT-derived measures of occipital bone thickness, occipital lobe width, mastoid area, and sulcal asymmetry (the asymmetry of intraparietal sulcus location from the longitudinal fissure). With the exception of the sulcal variable all measures significantly covaried with alpha AD. These findings caution that it may be important to determine cranial and brain parenchymal asymmetries where brain laterality is pertinent to studies of EEG.

Adolescent↗

PubMed1989

Bilateral alpha distribution and anatomic brain asymmetries.

The parieto-occipital (PO) index of the VEP alpha-afterdischarge (AD) was assessed bilaterally in normal subjects in three successive sessions separated by one-three weeks with two within-session retests. Correlations between PO values and asymmetries of occipital and parietal width, mastoid area, basal angle, cephalic, and plagiocephaly indices were established in simple correlation and stepwise multiple regression analysis. Occipital width, notably in the right hemisphere correlated reliably with the PO index in relaxed wakefulness and the vigilance task. The population having normal and reversed occipital brain width is predicted to have different parieto-occipital AD distribution. Some errors of lateral EEG measurements introduced by slant cranial deformity are discussed in order to call attention to the fact that anatomy-related lateral EEG changes may masquerade as cognition-related asymmetries.

Adolescent↗

PubMed1989

Defense mechanisms in risk of suicide and risk of violence.

This paper reports on an empirical study of defense mechanisms in 60 psychiatric inpatients. Eight defenses--compensation, denial, displacement, intellectualization, projection, reaction formation, regression, and repression--were studied in the context of a two-stage model of suicidal and violent behavior. The results showed that use of regression as a defense differentiated suicidal from nonsuicidal patients, and use of displacement differentiated violent from nonviolent patients. Repression tended to turn aggression inward, and projection and denial turned aggression outward.

Adult↗

PubMed1985

An empirical study on the "cathartic effect" of attempted suicide.

A cathartic effect of attempted suicide has been suggested, but few data are available to validate the concept. In this study we report on the relation between presuicidal and postsuicidal mood conditions in a group of 25 hospitalized suicide attempters and 50 control patients who were depressed but not suicidal. A significant decrease in depression was demonstrated to occur in the suicidal patients within a few days of hospitalization. This was not the case in depressed patients without prior suicide attempts. The drop in depression ratings can, therefore, be attributed to the suicide attempt. Possible explanatory factors are discussed. These findings indicate that the diagnosis of a suicide attempt in the absence of depression can only be reliably made on the basis of data pertaining to the presuicidal mood condition.

Abreaction↗

PubMed1982

Short-term naloxone administration in schizophrenic and manic patients. A World Health Organization Collaborative Study.

A double-blind study of the behavioral effects of short-term naloxone hydrochloride administration was performed in 32 schizophrenic and 26 manic patients in a World Health Organization collaborative project. There was a significant naloxone-associated reduction in overall physician-rated symptoms in schizophrenic patients concurrently treated with neuroleptic medication (N = 19) but not in medication-free schizophrenics (N = 13). Physician rating of auditory hallucinations showed significant naloxone-associated improvement for the total schizophrenic population, while self-ratings of auditory hallucinations showed improvement only in neuroleptic-treated schizophrenics. While further studies are needed to delineate these effects as to clinical significance, they may bear etiological implications for the psychobiology of schizophrenia, including the possibility of synergistic effects of dopamine and endorphin blockade. Naloxone produced no significant behavioral effects in manic patients. These findings are discussed with relationship to the hypotheses of endorphin involvement in schizophrenia and mania.

Adult↗

PubMed1980

Depression vulnerability and 5-hydroxytryptophan prophylaxis.

Previous studies have indicated that (1) The group of vital (endogenous) depressions encompasses a subgroup with a central serotonin (5-hydroxytryptamine; 5-HT) deficiency. (2) Abolition of this deficiency--with the aid of 5-hydroxytryptophan (5-HTP), a 5-HT precursor, or clomipramine, a 5-HT reuptake inhibitor--leads to abatement of depressive symptoms. It therefore seems plausible that the suspected 5-HT deficiency contributes to the development of depressive symptoms instead of resulting from them. (3) In a majority of patients, the suspected 5-HT deficiency persists even when the depressive symptoms have disappeared and the medication has been discontinued. This suggested that the disturbed central 5-HT metabolism is not a direct causal, but a predisposing factor. If so, abolition of the suspected 5-HT deficiency, e.g., with the aid of 5-HTP, would be expected to have a prophylactic effect. As predicted, 5-HTP was found in the present study to reduce the relapse rate in recurrent vital depressions with both a unipolar and bipolar course. The prophylactic effect was most pronounced in patients with persistent disorders of central 5-HT metabolism; this observation, however, requires corroboration. 5-HTP prophylaxis is the first aimed (i.e., pathological substrate-oriented) type of chemoprophylaxis known in psychiatry.

5-Hydroxytryptophan↗