Method for in situ detection of the mitochondrial function in neurons

Conventional studies of neuronal mitochondria have been limited to the use of purified preparations of isolated mitochondria, neural cell homogenates, living neurons, or brain slices. However, each technique has several drawbacks. Here, we demonstrate that the neuronal cell's membrane can be effectively permeabilized by saponin-treatment and that these permeabilized neurons can be used for qualitative and quantitative assessments of oxygen consumption in combination with registration of mitochondrial membrane potential and free [Ca2+] in the matrix. Under these conditions, the mitochondrial function can be studied without removing the mitochondria from their natural milieu thus avoiding the damage of the associated cytoskeleton and outer membrane. At the same time, the method allows the estimation of the mitochondrial function independently of other processes in the cell, and the easy manipulation of the milieu surrounding the mitochondria. Thus, the presented method offers the opportunity to study the neuronal mitochondrial function in situ and can also be applied to examine the mitochondrial function by other commonly used methods.     

Health impact assessment of particulate pollution in Tallinn using fine spatial resolution and modeling techniques

Background  

Health impact assessments (HIA) use information on exposure, baseline mortality/morbidity and exposure-response functions from epidemiological studies in order to quantify the health impacts of existing situations and/or alternative scenarios. The aim of this study was to improve HIA methods for air pollution studies in situations where exposures can be estimated using GIS with high spatial resolution and dispersion modeling approaches.     

Felt stigma and impact of epilepsy on employment status among Estonian people: exploratory study.

This article examines the impact of epilepsy and its treatment on employment status and the extent of stigma among patients with epilepsy. Clinical and demographic data concerning patients examined during a recent epidemiological survey were obtained from medical notes and postal self-completed questionnaires. Information was collected from 90 patients aged 16-70 years. A third of the respondents had been seizure-free during the last year. Thirty-nine percent were working full-time, 24% were working part-time and 11% were unemployed. Sixty-three percent from those working part-time or unemployed considered their epilepsy to be a significant reason for this. Overall, 55.4% believed they had been treated unfairly at work or when trying to get a job. Fifty-one percent of respondents felt stigmatized by epilepsy, 14% of them highly so. The level of employment among epileptic people was not lower than in the general population. The percentage of stigmatization in general and the percentage of the severely stigmatized was as high or even higher than in other studies. Occurrence of stigma and its severity depended first and foremost on the type of seizures. The frequency of seizures was not clearly related to this.     

Membrane-bound Phosphodiesterases in Rat Myocardium

Isoenzyme-specific phosphodiesterase (PDE) inhibitors are potential positive inotropic drugs. For evaluating such drugs in experimental models and to understand the physiological roles of the different isoenzymes, it is necessary to know what isoenzymes are present in the tissues studied. Rat myocardium has been reported to be devoid of the particulate cGMP-inhibited cAMP-PDE (type III isoenzyme). Here we re-evaluate the isoenzyme profile of rat myocardium. The cAMP-PDE isoenzyme patterns were studied by ion-exchange chromatography using siguazodan and rolipram, specific inhibitors of type III and IV isoenzymes, respectively. In contrast to earlier reports, type III isoenzyme was abundant in the particulate fraction. PDE III-specific antibodies depressed PDE activity and stained bands in Western blot with molecular masses 64 and 71 kDa. Type III isoenzyme of myocardial membranes was found to be unstable at 37°C which may explain why earlier investigators have failed to demonstrate its presence. The data presented in this paper show that rat heart particulate fraction contains two low K_m PDE isoenzymes, type III and type IV, in equal activities. Thus, in contrast to previous reports, this paper clearly shows the presence of considerable amounts of membrane-bound type III PDE isoenzyme in rat myocardium.     

Survival of patients with primary CNS tumours in Estonia

We studied a population-based survey that included 1417 patients with a primary central nervous system (CNS) tumour diagnosed in Estonia between 1986 and 1996. Survival rates at 1 and 5 years and median survival by histology and patient's age at diagnosis were estimated. Median survival time for all tumours was 33.2 months and 1- and 5-year survival rates were 59.3 and 46.0%, respectively. In multivariate analysis, younger age, better clinical condition (i.e. a Karnofsky Performance Status (KPS) score of 60 and more) and tumour histology were all dependent prognostic factors for better survival. Risk of death was more than 8 times greater for glioblastoma (Risk Ratio (RR) 8.31) and approximately seven times greater for anaplastic astrocytoma (RR 7.22) and other gliomas (RR 5.74) compared with meningiomas. Comparing the first (1986-1989) and the third (1994-1996) time periods, statistically significant improvements in survival occurred for all tumours and astrocytomas. Declines in survival during the second period (1990-1993) were statistically significant for all the tumour groups, but the most striking decrease took place in patients with glioblastoma. Age-specific rates showed that the increase in survival was more evident for patients aged between 45 and 64 years.     

The impact of adverse life events and the serotonin transporter gene promoter polymorphism on the development of eating disorder symptoms

Adverse life events have been shown to predict weight fluctuations and dietary restraint, as well as eating disorders during adolescence or early adulthood. Since the s-allele carriers of the 5-HTT gene-linked polymorphic region (5-HTTLPR) are biologically more reactive to stress related stimuli, we aimed to explore whether the eating disturbances are predicted by environmental stressors and moderated by the 5-HTTLPR genotype. The sample was based on the younger cohort of the Estonian Children Personality, Behaviour and Health Study and included those participating in its second and third wave. The history of stressful life events was self-reported at age 15. Data on eating behaviour and attitudes, anxiety, impulsivity and depressiveness were collected at age 18. The effect of the adverse life events on binge eating and on drive for thinness was found to be moderated by the 5-HTTLPR. Adolescent girls who at age 15 had reported a history of frequent adverse life events had elevated scores in EDI-2 Bulimia subscale at age 18 if they were carrying the s-allele. The effect of the s-allele on binge eating was even more pronounced when solely the experience of sexual abuse was considered. The interaction effect of the 5-HTTLPR and the past sexual abuse was also observed on drive for thinness. These data give further support to the idea that adverse life events in childhood may heighten susceptibility to serotonergic dysregulation following stress, and suggest that in individuals vulnerable to eating disorders this may result in disturbed eating behaviours.     

Seizures, ataxia, and neuronal loss in cystatin B heterozygous mice

Unverricht-Lundborg disease (EPM1) has been considered to be an autosomal-recessive disease related with loss of function mutations in the gene encoding cystatin B. Although heterozygous carriers are generally asymptomatic, earlier studies in Finnish EPM1 families have reported minor symptoms together with slight changes in the EEG recordings also in near relatives of patients. Here we tested the hypothesis that EPM1 phenotype is expressed also in heterozygous subjects using 17-month-old cystatin B deficient mice as a model of disease. Western blot analysis demonstrated a 50% decrease in cystatin B expression in the cerebellum of these animals. Heterozygous mice showed significantly impaired rotarod performance and were weaker in the grid test. Also the total seizure-rating score of heterozygous animals was higher than in wild-type mice. The stereological analysis revealed a significant decrease in the number of neurons in cerebral cortex and the granule cell layer of cerebellum. These results suggest that partial decrease in cystatin B expression in heterozygous mice could lead to the development of mild EPM1 phenotype.