Ultrastructural and functional characterization of satellitosis in the human lateral amygdala associated with Ammon’s horn sclerosis

The amygdala displays neuronal cell loss and gliosis in human temporal lobe epilepsy (TLE). Therefore, we investigated a certain type of gliosis, called satellitosis, in the lateral amygdala (LA) of TLE patients with Ammon’s horn sclerosis (AHS, n = 15) and non-AHS (n = 12), and in autopsy controls. Satellite cells were quantified using light and electron microscopy at the somata of Nissl-stained and glutamic acid decarboxylase-negative projection neurons, and their functional properties were studied using electrophysiology. Non-AHS cases suffered from ganglioglioma, cortical dysplasia, Sturge–Weber syndrome, astrocytoma WHO III–IV, Rasmussen’s encephalitis, cerebral infarction and perinatal brain damage. TLE cases with AHS had a more prominent satellitosis as compared to non-AHS and/or autopsy cases, which correlated with epilepsy duration but not age. At ultrastructural level, the predominant type of satellite cells occurring in both AHS and non-AHS cases displayed a dark cytoplasm and an irregularly shaped dark nucleus, whereas perineuronal glial cells with a light cytoplasm and light oval nucleus were much rarer. Satellite cells expressed time- and voltage-dependent transmembrane currents as revealed by patch-clamp recordings typical for ‘complex’ glia, although only 44% of satellite cells were immunostained for the chondroitin sulfate proteoglycan NG2. Together, the perineuronal cells described here were a heterogenous cell population regarding their NG2 expression, although they resembled NG2 cells rather than bona fide oligodendrocytes and astrocytes based on their ultrastructural and electrophysiological characteristics. Thus, perineuronal satellitosis as studied in the LA seems to be a hallmark of AHS-associated TLE pathology in patients suffering from intractable epilepsy.     

Socioeconomic indicators and prosthetic replacement of missing teeth in a working-age population–Results of the Study of Health in Pomerania (SHIP)

Abstract – Objectives: To analyse the possible effects of the socioeconomic status (SES) on the prosthetic replacement of missing teeth in working‐age people and to explore the role of potential confounders. Methods: Cross‐sectional data were collected from 2310 German adults aged 30–59 years. The relationship between each of the three SES indicators (education, income, and occupational status) and dental prostheses were examined by multinomial logistic regression analyses. For that, partially dentate participants with suboptimal and no replacement of missing teeth were compared with partially dentate participants having optimal replacement. Potential confounders (age, sex, dental status, social network and social support) were entered if their inclusion in the model led to ≥10% change in the coefficient of interest. Results: Social network and social support did not meet the criterion for confounding. In the maxilla, having no replacement was positively associated with lower categories for each of the three SES indicators [Odds ratios (OR) between 1.6 and 2.1; 95% confidence intervals (CI) between 1.1 and 3.4]. Low occupational status was the single predictor for suboptimal dental prostheses (OR = 3.2; 95% CI: 1.6–6.2). In the mandible, occupational status showed no association with the prosthetic status, whereas low educational level and low household income were determinants for having no replacement (OR = 1.9 and 1.9, 95% CI: 1.0–3.5 and 1.1–3.0, respectively). Low household income was the single determinant for suboptimal replacement of missing teeth (OR = 2.4, 95% CI = 1.1–5.2). Conclusion: The findings may indicate the relevance of the financing of prosthodontic treatment. The strong association between various forms of upper dentures and occupational prestige can be seen as key contributing concept to how individuals′ characteristics affect the outcome in prosthodontic care.     

Cone-beam computed tomography for assessment of palatal displaced canine position: A methodological study

Objective: To assess the inter- and intraexaminer reliability of a measurement method for evaluation of eruption angles and position of palatal displaced canines (PDCs) with cone-beam computed tomography (CBCT) images and to test the validity of the measured angles on a dry skull.Materials and Methods:Twenty patients (eight boys, 12 girls; age 11.4 ± 1.2 years) were randomly chosen among 67 patients from a study evaluating the interceptive effect of extracting the deciduous canine in children with PDCs. In total, 60 images were analyzed, because each patient had three CBCT examinations (baseline, 6-month control, and endpoint). Two observers assessed the following measurements twice: mesioangular and sagittal angle, vertical position, canine cusp tip, and canine apex to dental arch. The validity of the angular measurements was tested against angular measurements on a dry skull using mathematical formulations.Results:The inter- and intraexaminer mean differences for angular and linear measurements were all low and statistically insignificant (P > .05). The mean differences between the physical and 3D measurements were 0.5 ± 0.39 mm for the sagittal angle and 0.22 ± 0.19 mm for the mesioangular angle.Conclusions:Linear and angular measurements on CBCT images are accurate and precise and can be used to assess the precise position of a PDC.     

Retarded kindling progression in mice deficient in the extracellular matrix glycoprotein tenascin-R

Purpose:   We investigated the role of the extracellular matrix glycoprotein tenascin-R (TNR) in formation of a hyperexcitable network in the kindling model of epilepsy. The idea that TNR may be important for this process was suggested by previous studies showing that deficiency in TNR leads to abnormalities in synaptic plasticity, perisomatic GABAergic inhibition and more astrocytes in the hippocampus of adult mice.
Methods:   Constitutively TNR deficient (TNR−/−) mice and their wild-type littermates received repeated electrical stimulation in the amygdala over several days until they developed fully kindled generalized seizures at which time their brains were studied immunohistochemically.
Results:   In TNR−/− mice, kindling progression was retarded compared with wild-type littermate controls. Morphological analysis of the mice used for the kindling studies revealed that, independently of genotype, numbers of parvalbumin-positive interneurons in the dentate gyrus correlated positively with afterdischarge threshold alterations in kindled mice. The kindling-induced increase in the number of S100 expressing astrocytes in the dentate gyrus was enhanced by TNR deficiency and correlated negatively with the kindling rate.
Discussion:   Our data support the view that TNR promotes formation of a hyperexcitable network during kindling and suggest that an increase in S100-expressing astrocytes may contribute to retarded epileptogenesis in TNR−/− mice.     

Localization, release and bioavailability of pollen allergens: the influence of environmental factors

Allergens are integral constituents of plants or animals and their normal functions and localization are being characterized. To trigger responses in humans, allergens must become bioavailable and the role of air pollutants--for example diesel-exhaust particles --in this process is causing concern. Finally, the fact that some pollen releases eicosanoid-like proinflammatory mediators may have wide implications.     

Lowering of the potassium concentration induces epileptiform activity in guinea-pig hippocampal slices

Extra- and intracellular recording techniques were used to study the epileptiform activity generated by guinea-pig hippocampal slices perfused with low potassium containing artificial cerebrospinal fluid. Extracellular field potentials were recorded in CA1 and CA3 regions along with intracellular recordings in CA3 subfield. Reduction of the extracellular potassium concentration [K(+)](o) from 4 to 2 mM caused a transient neuronal hyperpolarisation which was followed by a repolarisation and subsequent depolarisation period. Paroxysmal depolarisation shifts occurred during the transient hyperpolarisation period while epileptic field potentials (EFP) appeared in the late repolarisation or early depolarisation phase. EFP elicited by reduction of [K(+)](o) were neither affected by blockade of N-methyl-D-aspartate (NMDA) glutamate-subreceptor or gamma aminobutyric acid receptor, nor by application of the organic calcium channel blocker nifedipine or the anticonvulsant drugs carbamazepine and valproic acid. Upon application of non-NMDA glutamate-subreceptor blocker the EFP were abolished in all trials, while application of the organic calcium channel blocker verapamil only suppressed the EFP in some cases. The results point to a novel mechanism of epileptogenesis and may provide an in vitro model for the development of new drugs against difficult-to-treat epilepsy.