Most dystrophic neurites in the common 5xFAD Alzheimer mouse model originate from axon terminals.

How dystrophic neurites form around amyloid plaques is a key aspect of understanding the early pathophysiology of Alzheimer's disease. At present, three hypotheses prevail: (1) dystrophies result from extracellular amyloid-beta (Aß) toxicity; (2) dystrophies results from accumulation of Aß into distal neurites; and (3) dystrophies represent blebbing of the somatic membrane of a neuron with high Aß load. We utilized a unique feature of the common 5xFAD AD mouse model to test these hypotheses. Cortical layer 5 pyramidal neurons show intracellular APP and Aß accumulation before amyloid plaque formation while dentate granule cells in these mice show no APP accumulation at any age. However, the dentate gyrus shows amyloid plaques by 3 months of age. By a careful confocal microscopic analysis we found no evidence of severe degeneration in amyloid laden layer 5 pyramidal neurons in contrast to hypothesis 3. Using injecting red fluorescent marker into lateral entorhinal projection neurons in 5xFAD mice with endogenous green fluorescent protein (GFP) in dentate granule cells we could demonstrate that all dystrophies is outer molecular layer originate from the axon terminal of entorhinal projection neurons. Immunostaining with vesicular glutamate transporter supported the axonal nature of the dystrophies in the acellular dentate molecular layer. We observed few small dystrophies in the GFP labeled granule cell dendrites. In general GFP labeled dendrites appear normal around the amyloid plaques. These findings favor hypothesis 2 as the most likely mechanism of dystrophic neurite formation.

Black stain and dental caries in primary teeth of Tunisian preschool children.

AIM: To assess the prevalence of black tooth stains and to investigate its correlation with caries experience in the primary dentition of 3-5-year-old children in the region of Monastir, Tunisia. METHODS: It was a descriptive cross-sectional study involving children in preschool establishments in Monastir, Tunisia. It consisted of an oral examination of 393 children and data collection through a questionnaire completed by parents. ANOVA test and Pearson Chi-square test were used to assess the prevalence of black stains and its association with dental caries. RESULTS: The overall mean decayed, missing, and filled teeth (dmft) index was 1.42 ± 0.1. Caries prevalence was 49.9%. Of all the children involved, 6.1% had black stains. A statistically significant relationship was found between black stain and the prevalence of early childhood caries (p = 0.047). However, the association with the dmft index was not statistically significant (p = 0.08). CONCLUSION: Preschool children with black tooth stain had lower dental caries experience. The results of the present study suggest that black stains are a protective factor for early childhood caries. More studies are needed to explore the risk factors of black stains.

Cardiac PET imaging of 18F-FDG metabolism: study of healthy and infarcted hearts of rats.

This paper, considers the evolution of a method presented previously by authors to correct for cross contamination effect on the dynamic image sequences and shows how this development allows for a robust voxel by voxel implementation yielding parametric images for healthy and unhealthy subjects. Our approach is based on the decomposition of image pixel intensity into blood and tissue components using Bayesian statistics. The method uses an a priori knowledge of the probable distribution of blood and tissue in the images. Likelihood measures are computed by a General Gaussian Distribution (GGD) model. Bayes' rule is then applied to compute weights that account for the concentrations of the radiotracer in blood and tissue and their relative contributions in each image pixel. We tested the method on a set of dynamic cardiac (18)F-fluoro-deoxy-d-glucose PET of healthy rats and unhealthy rats. The results show the benefit of our correction on the generation of parametric images of myocardial metabolic rates for glucose (MMRG).

Extraction of time activity curves from gated FDG-PET images for small animals' heart studies.

We introduce a new approach to extract the input function and the tissue time activity curve from dynamic ECG-gated (18)F-FDG PET images. These curves are mandatory to model the myocardium metabolic rate of glucose for heart studies. The proposed method utilizes coupled active contours to track the myocardium and the blood pool deformations. Furthermore, a statistical approach is developed to model the blood and tissue activities and to correct for spillovers. The developed algorithm offers a reliable alternative to serial blood sampling for small animal cardiac PET studies. Indeed, the calculated MMRG value differs by 1.54% only from the reference value.

Anti-centromere antibodies as a marker of Raynaud's phenomenon in pediatric rheumatologic diseases.

To examine the possible relationship between anti-centromere antibodies (ACA) and pediatric rheumatologic diseases, we investigated the presence of ACA (using enzyme immunoassay) in the sera of 45 children and adolescents with such diseases and compared the results with a group of 42 age- and gender-matched healthy subjects. ACA were present ( > or =10 U/ml) in three out of five patients (60%) with scleroderma (SCD), in seven out of 16 (43.8%) patients with systemic lupus erythematosus (SLE), in two out of five patients (40%) with mixed connective tissue disease (MCTD), in one out of four patients (25%) with dermatomyositis (DMS), and in two out of 14 patients (14.3%) with juvenile rheumatoid arthritis (JRA). ACA were also detected in a single patient with anti-phospholipid syndrome (APL) who had digital gangrene and hemiparesis, as well as in two healthy subjects. ACA positivity was related to the presence of Raynaud's phenomenon in the studied sample, as 86% of patients suffering from the phenomenon were ACA positive. ACA positivity was associated with older age, high blood pressure and high erythrocyte sedimentation rate (ESR) values, and lower hemoglobin and weight and height percentile values. It was also higher among anti-nuclear antibody-positive subjects. Raynaud's phenomenon and ACA positivity shared almost the same clinical and laboratory associations in the studied patients. Thus, ACA are probably among the markers of Raynaud's phenomenon in pediatric rheumatologic diseases. Their value as predictors of future development of the phenomenon needs further evaluation.

Antiperinuclear factor in the diagnosis of juvenile rheumatoid arthritis.

The antiperinuclear factor (APF) was estimated by immunofluorescent microscopy in the sera of 32 children and adolescents with juvenile rheumatoid arthritis (JRA) in comparison to a group of 16 children and adolescents with other rheumatologic disorders and a group of 20 age-matched healthy subjects. The APF was detected in 17 children with JRA (53%), in only one patient in the group of other rheumatologic disorders (6%), and in 2 healthy children (10%). Accordingly, APF had a sensitivity of 53%, a specificity of 92%, and a diagnostic efficiency of 74% in our series. APF was found to have a higher diagnostic gain in rheumatoid factor (RF) seronegative cases than did the RF in APF negative cases, meaning a higher sensitivity of APF as compared to the RF. The APF seropositivity was neither altered by the use of corticosteroids nor influenced by the age, gender, duration of illness, or number of joints affected. Three out of 5 patients with JRA had the APF detected in their synovial fluid; they were running rather a severe course of illness. The use of the APF could be an aid in the diagnosis of JRA.

Acute hemorrhagic conjunctivitis in Tunisia. Report of viral isolations.

Acute hemorrhagic conjunctivitis (AHC), a new disease entity first reported in 1969, has since become pandemic throughout the world. In Tunisia during an epidemic in 1972 to 1973 we studied 25 cases of AHC, which were characterized by explosive onset of lid edema, chemosis, conjunctival hemorrhages, follicular hypertrophy, and epithelial keratitis. Clinical signs peaked in 48 hours and cleared without sequelae in five to seven days. Paired acute- and convalescent-phase sera from six of the patients showed a rising titer of neutralizing antibody to the prototype strain of AHC virus (J6 70/71), which was isolated in Japan. Two viral isolates from Tunisian patients were also antigenically related to the Japanese strain, indicating that a single etiologic agent (a new member of the picornavirus group) is probably responsible for the current pandemic of AHC.