Biomedical subjects

J Scharfetter

Publications and source records attributed to J Scharfetter.

7 recordsLinked to original sources

PubMed2001

Inverse relation between stimulus intensity and seizure duration: implications for ECT procedure.

A retrospective analysis of the effects of electroconvulsive therapy (ECT) was performed for two groups of 11 patients matched according to age (mean age, 52 years), sex, and diagnosis. Group 1 received ECT according to the age-dose protocol; group 2 was treated according to the titration method. A higher dose relative to the seizure threshold appeared to shorten the seizure duration. At the first treatment, the correlation between stimulus intensity and seizure duration was negative. In the titration group, the initial mean charge of 91 mC resulted in a seizure duration of 51 s, whereas in the age-dose group the seizure duration of 31 s was significantly shorter despite a higher mean charge of 312 mC. Seizure duration decreased during the ECT course in the group treated first at low dose (titrated) and then at 2.5 times the initial threshold. High stimulus intensity represented adequate treatment, although it produced short seizures. Thus, seizure duration proved to be an unreliable guideline for effective treatment. Furthermore, focus on seizure duration led to frequent high-dose restimulation in the elderly. The titration method obviates inadequate or excessive charges because the seizure threshold must first be determined.

Adult↗

PubMed2001

Dopamine receptor polymorphisms and drug response in schizophrenia.

The elucidation of the assumed genetic contribution to the predisposition towards schizophrenia is a scientifically challenging enterprise with considerable impact on therapeutic possibilities. A pharmacogenetic approach, targeted to the clinical response to medication, provides a promising alternative as a means of investigation, with the prospect of gaining knowledge about the disease and of developing an individually tailored medical treatment. This review will focus on dopamine receptor genes which have, due to the dopamine hypothesis of schizophrenia, been a prime target in pharmacogenetic studies of schizophrenia. The current status of the studies results will be displayed and future prospects will be discussed.

Humans↗

PubMed2000

Association studies of candidate genes in bipolar disorders.

The aim of the investigation was to test genes for predisposition to bipolar affective disorder. Therefore, we studied candidate genes in a sample of unrelated patients (n = 102) and healthy controls (n = 79) of Austrian origin, searching for a possible association between polymorphic DNA markers of 5 candidate genes (serotonin transporter, 5-HTT; serotonin 2a receptor, 5-HT2a; dopamine D2 receptor, DRD2; dopamine D3 receptor, DRD3; dopamine transporter, DAT1) and bipolar disorder. There was an association between allelic and genotypic frequencies of 5-HTT and affection status (p = 0.014 and p = 0.017, respectively). However, after correction for multiple comparisons (Bonferroni), these results did not remain significant. Nevertheless, the findings might suggest that alterations in the structure of 5-HTT are involved in the pathogenesis of bipolar disorder, which could have major implications in treatment. No association between 5-HT2a, DRD2, DRD3, DAT1 and bipolar disorder was found.

Adult↗

PubMed1999

Possible association between childhood absence epilepsy and the gene encoding GABRB3.

BACKGROUND: Childhood Absence Epilepsy (CAE) is considered to have a predominantly, perhaps exclusively, genetic background. To date, genes responsible for susceptibility to CAE have not been identified. The object of the present study was to test association between CAE and the genes encoding the gamma-aminobutyric acid (GABA) type-A receptor subunits alpha 5 (GABRA5) and beta 3 (GABRB3) located on the long arm of chromosome 15 (15q11-q13). METHODS: A family-based candidate gene approach was applied: 50 Austrian nuclear families ascertained for the presence of an affected child were investigated. GABRA5 and GABRB3 subunit genes were genotyped using DNA gained from peripheral blood samples by Polymerase Chain Reactions (PCR). Genetic association was tested using a Monte Carlo Version of the multi-allele Transmission-Disequilibrium Test (TDT). RESULTS: The TDT displayed significant overall association with GABRB3 (p = .0118). CONCLUSIONS: The present data suggest that the tested polymorphism may be either directly involved in the etiology of CAE or in linkage disequilibrium with disease-predisposing sites.

Adolescent↗

PubMed1999

Anticipation in schizophrenia.

In various genetic disorders it has been observed that the severity of illness increases and the age at onset decreases in successive generations. This phenomenon is termed anticipation. We sampled 15 families, totalling 123 individuals with at least one person affected by a disease of the schizophrenia spectrum in the index generation in each family (IG; n = 33 affected out of a total of 67 individuals) and in the parental generation (PG; n = 16 affected out of a total of 56 individuals). The pedigrees had originally been identified for linkage studies in schizophrenia. We found a significant difference between IG and PG regarding severity of illness as defined by Kendler et al's hierarchical model of categories of the schizophrenia spectrum (p = 0.001). Age at onset was significantly earlier in the IG (21.6 +/- 6.6 years) than in the PG (40.2 +/- 9.2 years) (p = 0.0001). We excluded a potential birth cohort effect by investigating a control sample consisting of two non-overlapping birth cohorts of patients with schizophrenia. Age at onset between the two groups of the control sample did not differ. Anticipation is an important aspect in the investigation of a possible genetic basis, at least for the familial form of schizophrenia. Active research on a molecular level with special emphasis on trinucleotide repeats might be able to shed further light on this phenomenon.

Adult↗

PubMed1999

Dopamine D3 receptor gene polymorphism and response to clozapine in schizophrenic Pakastani patients.

The dopamine D3 receptor (DRD3) appears to play an important role in the mediation of antipsychotic drug action. Genetic association of treatment response to the atypical antipsychotic drug clozapine with the DRD3 polymorphism Ser9Gly was investigated in a sample of 32 schizophrenic patients. We found association of treatment response with allele Gly-9 (P=0.0058) and with genotypes consisting of Gly-9 (P=0.033) by this pharmacogenetic approach. A combined analysis with two previous studies (Shaikh et al., Hum. Genet. 97 (1996) 714-719; Malhotra et al., Mol. Psychiatry 3 (1998) 72-75) further substantiates these results (P=0.0041).

Adult↗

PubMedDate not supplied

Myo-inositol in depressive and healthy subjects determined by frontal 1H-magnetic resonance spectroscopy at 1.5 tesla.

Myo-inositol (mI) as a precursor in the phosphatidylinositol second messenger system has been reported to be reduced in depression. By means of proton-magnetic resonance spectroscopy (1H-MRS) the mI levels in the frontal brain were investigated in vivo in the present study. Twenty-two patients (mean age: 42.8 +/- 10.7 years) with depressive episodes according to ICD 10 (HAMD score > 17) were compared to 22 healthy subjects (28.0 +/- 5.3 years). Two voxels (30 x 20 x 20 mm3) in the frontal lobes were examined in a Siemens Magnetom SP 4000 at 1.5 T (STEAM sequence: TR = 3500 ms, TE = 55 ms). With the total creatine (Cr) as an internal standard, mI/Cr ratios were calculated to follow the mI levels. In the left frontal lobe, mI/Cr was 0.43 +/- 0.06 in depressive patients and 0.46 +/- 0.07 in healthy subjects; concerning the right frontal lobe, mI/Cr was 0.46 +/- 0.08 and 0.48 +/- 0.06, respectively. There were neither significant differences between the two groups nor between the hemispheres. Since there was a significant positive correlation (R = 0.6) between the age and the mI/Cr in the right frontal lobe of depressed patients, age matched pairs analysis was performed (n = 2 x 10, in each group: nine females, one male, < 40 years). In the right frontal lobe, the patients' mI/Cr of 0.40 +/- 0.05 was now significantly lower than the controls' mI/Cr of 0.45 +/- 0.06. However, most of the patients were on antidepressive medication. Interestingly, it was exactly this group of patients which showed significantly lower mI levels. We regard our investigation as a pilot study which suggests an influence of age and antidepressants on mI levels and should be taken into consideration in further investigations in depressive patients.

Adult↗