Biomedical subjects

Athanasios Maras

Publications and source records attributed to Athanasios Maras.

5 recordsLinked to original sources

PubMed2006

[Reduced serotonin levels in platelet-free plasma of adolescents with externalizing behaviour problems].

OBJECTIVES: A serotonergic dysfunction, in particular a reduced serotonergic neurotransmission in the frontal cortex and limbic brain regions, has been discussed in connection with the aetiology of aggressive and impulsive behaviour. Assessment of the activity in the central serotonergic system in children and adolescents is limited due to its technical complexity and ethical restrictions. Therefore, peripheral serotonergic parameters have been used as a model to obtain deeper insight into central serotonergic functions. The aim of this investigation is to examine the significance of plasma serotonin measurement with regard to behavioural problems in adolescents at risk for psychopathology. METHODS: Within the framework of a prospective longitudinal study of children at risk, serotonin levels in platelet-free blood plasma were measured in a group of n = 10 adolescents aged 15 years with persistent externalizing behaviour (T-score > or = 60 on the "Externalizing Problems" scale of the CBCL) and in a control group of n = 20 mentally undisturbed adolescents. Groups were matched according to age and gender. Externalizing behaviour was assessed by means of a parent questionnaire, the Achenbach Child Behavior Checklist (CBCL). RESULTS: Significantly lower levels of plasma serotonin were found in adolescents with persistent behaviour problems than in the control group. Significant negative correlations between serotonin levels and the CBCL scales "Aggressive Behavior" and "Externalizing Problems" were obtained for the total sample. CONCLUSIONS: Earlier findings that described a serotonergic deficit as a key mechanism in the manifestation of aggressive and antisocial behaviour are confirmed for adolescents at risk taken from a community sample.

Adolescent↗

PubMed2004

Altered thalamic membrane phospholipids in schizophrenia: a postmortem study.

BACKGROUND: Membrane lipids are important mediators of neuronal function. In a postmortem study, we measured membrane lipid components in the left thalamus of schizophrenic patients. This region might play an important role in the pathophysiology of schizophrenia and has not been studied thus far with respect to its membrane lipid composition. METHODS: The study included 18 chronic schizophrenic patients and 23 healthy control subjects. Using lipid extraction and thin-layer chromatography, we measured membrane phospholipids, galactocerebrosides 1 and 2, and sulfatides in thalamus homogenate. RESULTS: The main membrane phospholipid phosphatidylcholine and the major myelin membrane components sphingomyelin and galactocerebrosides 1 and 2 were found to be decreased in schizophrenic patients. In contrast, phosphatidylserine was increased. These lipid contents did not correlate with postmortem intervals and medication doses. There was no difference in the membrane phospholipids lysophosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, and phosphatidylglycerol or in sulfatides. CONCLUSIONS: Our results confirm findings of magnetic resonance imaging, postmortem, and gene expression studies. They support the notion of an increased phospholipid breakdown in schizophrenia as a sign for decreased myelination and oligodendrocyte dysfunction.

Aged↗

PubMed2003

Association of testosterone and dihydrotestosterone with externalizing behavior in adolescent boys and girls.

BACKGROUND: While an association between androgens and different types of aggression has been well documented in male offenders, the influence of androgens on externalizing behavior in adolescents at risk for antisocial behavior has not been investigated so far. METHODS: Plasma levels of the main androgen metabolites testosterone (T) and 5alpha-dihydrotestosterone (DHT) were measured in N = 87 fourteen-year-old (36 boys, 51 girls) from a prospective longitudinal study of children at risk. Externalizing behavior at age 8, 11 and 14 was assessed using the Achenbach Child Behavior Checklist (CBCL) and Teacher Report Form (TRF). RESULTS: Significant higher androgen levels (T, DHT) were found in male, but not in female adolescents with elevated scores of externalizing behavior. Moreover, boys with persistent externalizing behavior exhibited the highest levels of plasma androgens. CONCLUSIONS: There is a link between T, DHT and externalizing behavior in male adolescents at risk for psychopathology. Due to the findings of highest androgen levels in boys with persistent externalizing behavior, a role of androgens in the development of disruptive or later antisocial disorders can be hypothesized.

Adolescent↗

PubMed2003

[Hawaiian baby rose wood: case report of an argyreia nervosa induced toxic psychosis].

An increase of intoxications in persons using psychoactive plants and mushrooms can be observed. Mainly adolescents are experimenting with this group of plants for its hallucinogenic effects and easy and cheap availability. A case of a toxic psychosis with hallucinations, disturbances of orientation and psychomotoric agitation and anxiety after the intake of Hawaiian baby wood rose seed, an exotic ergotalkaloid containing plant often misused for its hallucinogenic effect is reported. Other drug-induced psychosis (e.g. LSD-psychosis), schizophrenic episodes or anticholinergic drug-induced intoxications have to be excluded. Regarding the increasing spreading of the misuse of psychoactive plants in Europe and North America intoxications with severe fatal sequelae have to be expected for the future. The knowledge of the clinical picture is important for correct diagnosis and treatment.

Adolescent↗

PubMed2002

Steroid synthesis inhibition with ketoconazole and its effect upon the regulation of the hypothalamus-pituitary-adrenal system in healthy humans.

Steroid synthesis inhibitors are commonly used in the treatment of patients with Cushing's disease, but may also improve psychopathology in hypercortisolemic depressed patients. Since glucocorticoids exert a negative feedback at pituitary and supra-pituitary levels, the inhibition of steroid synthesis may lead to increased expression of corticotropin-releasing hormone (CRH) and arginine vasopressin (AVP). We studied the effect of treatment with 800 mg ketoconazole (3 weeks) upon the concentrations of basal plasma cortisol in the evening, corticosteroid-binding globulin (CBG), dehydroepiandrosterone-sulfate (DHEA-S), and ACTH as well as the concentrations of cortisol, CRH, and AVP in cerebrospinal fluid (CSF) at 8.30 h in 10 healthy, male volunteers. While we found cortisol plasma concentrations to be unchanged, we noted a significant increase in ACTH (post: 45.1+/-43.5; pre: 14.2+/-5.2 pmol/l; F(1,8)=9.78, p<0.02) and CBG concentrations (post: 38.8+/-4.3; pre: 31.9+/-4.2 microg/l), but DHEA-S plasma concentrations declined (post: 1.75+/-1.83; pre: 2.75+/-2.80 mg/l; F(1,8)=7.9, p<0.03). CRH concentrations in CSF were unchanged after treatment (post: 62.5+/-15.9; pre: 63.7+/-13.9 pg/ml), while there was a trend for AVP concentrations to rise during treatment (post: 2.52+/-1.18; pre: 1.92+/-0.96 pg/ml; paired t=-1.9, p<0.1). Cortisol CSF concentrations declined in the elderly (pre: 52.5+/-23.2; post: 26.7+/-4.6 nmol/l), but not in the young subgroup (pre: 15.6+/-11.3; post: 27.7+/-9.4 nmol/l). We thus conclude that the treatment of healthy controls with steroid-synthesis inhibitors does not lead to a major increase in CRH secretion.

Adult↗