Molecular Characterization of Three Canine Models of Human Rare Bone Diseases: Caffey,van den Ende-Gupta,and Raine Syndromes

One to two percent of all children are born with a developmental disorder requiring pediatric hospital admissions. For many such syndromes, the molecular pathogenesis remains poorly characterized. Parallel developmental disorders in other species could provide complementary models for human rare diseases by uncovering new candidate genes, improving the understanding of the molecular mechanisms and opening possibilities for therapeutic trials. We performed various experiments, e.g. combined genome-wide association and next generation sequencing, to investigate the clinico-pathological features and genetic causes of three developmental syndromes in dogs, including craniomandibular osteopathy (CMO), a previously undescribed skeletal syndrome, and dental hypomineralization, for which we identified pathogenic variants in the canine SLC37A2 (truncating splicing enhancer variant), SCARF2 (truncating 2-bp deletion) and FAM20C (missense variant) genes, respectively. CMO is a clinical equivalent to an infantile cortical hyperostosis (Caffey disease), for which SLC37A2 is a new candidate gene. SLC37A2 is a poorly characterized member of a glucose-phosphate transporter family without previous disease associations. It is expressed in many tissues, including cells of the macrophage lineage, e.g. osteoclasts, and suggests a disease mechanism, in which an impaired glucose homeostasis in osteoclasts compromises their function in the developing bone, leading to hyperostosis. Mutations in SCARF2 and FAM20C have been associated with the human van den Ende-Gupta and Raine syndromes that include numerous features similar to the affected dogs. Given the growing interest in the molecular characterization and treatment of human rare diseases, our study presents three novel physiologically relevant models for further research and therapy approaches, while providing the molecular identity for the canine conditions.     

D-BRAIN: Anatomically Accurate Simulated Diffusion MRI Brain Data

Diffusion Weighted (DW) MRI allows for the non-invasive study of water diffusion inside living tissues. As such, it is useful for the investigation of human brain white matter (WM) connectivity in vivo through fiber tractography (FT) algorithms. Many DW-MRI tailored restoration techniques and FT algorithms have been developed. However, it is not clear how accurately these methods reproduce the WM bundle characteristics in real-world conditions, such as in the presence of noise, partial volume effect, and a limited spatial and angular resolution. The difficulty lies in the lack of a realistic brain phantom on the one hand, and a sufficiently accurate way of modeling the acquisition-related degradation on the other. This paper proposes a software phantom that approximates a human brain to a high degree of realism and that can incorporate complex brain-like structural features. We refer to it as a Diffusion BRAIN (D-BRAIN) phantom. Also, we propose an accurate model of a (DW) MRI acquisition protocol to allow for validation of methods in realistic conditions with data imperfections. The phantom model simulates anatomical and diffusion properties for multiple brain tissue components, and can serve as a ground-truth to evaluate FT algorithms, among others. The simulation of the acquisition process allows one to include noise, partial volume effects, and limited spatial and angular resolution in the images. In this way, the effect of image artifacts on, for instance, fiber tractography can be investigated with great detail. The proposed framework enables reliable and quantitative evaluation of DW-MR image processing and FT algorithms at the level of large-scale WM structures. The effect of noise levels and other data characteristics on cortico-cortical connectivity and tractography-based grey matter parcellation can be investigated as well.     

Evidence for a pertussis toxin sensitive calcium entry pathway in thyroid FRTL-5 cells

Receptor-mediated calcium entry was investigated in Fura 2 loaded FRTL-5 cells. The purinergic agonist ATP activated the release of sequestered calcium and the entry of extracellular calcium. Downregulation of protein kinase C (PKC) substantially enhanced the ATP-evoked calcium entry. Pretreatment of the cells with pertussis toxin (Ptx) decreased the ATP-evoked calcium entry by 56% and the release of sequestered calcium by 34%. In PKC-downregulated cells, the effect of Ptx treatment on the ATP-evoked increase in [Ca²⁺]_iwas 73% and 44%, respectively. Phorbol myristic acetate (PMA) decreased the ATP-evoked calcium entry to the same extent as Ptx. In Ptx-treated cells, the ATP-evoked influx of ⁴⁵Ca²⁺ was attenuated. Stimulation of the cells with P_2p-purinergic agonist GTP evoked no entry of calcium, although GTP released the same amount of sequestered calcium as did ATP. PKC downregulation or pretreatment with Ptx had no effects on the GTP-evoked responses, whereas PMA decreased the GTP-evoked release of calcium. We conclude that the ATP-activated rapid calcium entry pathway is a second messenger-operated calcium channel. © 1995 Wiley-Liss, Inc.     

Genetic and environmental influences on the relationship between aggression and hyperactivity-impulsivity as rated by teachers and parents.

This study examined genetic and environmental contributions to the covariance between aggression and hyperactivity-impulsivity as rated by twins' teachers and parents. Sex-differences in these genetic and environmental contributions and rater bias/sibling interaction effects were of interest as well. Part of an ongoing nation-wide twin-family study of behavioral development and health habits, the sample consisted of 1636 Finnish twin pairs ascertained from five consecutive and complete twin birth cohorts. Data were collected at ages 11-12, using teacher and parental rating forms of the Multidimensional Peer Nomination Inventory. Bivariate analyses were performed using structural equation modeling allowing sex-limitation effects. Results show that, in addition to significant genetic and environmental influences specific to each behavior, aggression and hyperactivity-impulsivity share common genetic and environmental etiology. Results provide evidence that both genetic and environmental factors are important in creating the observed correlation between aggression and hyperactivity-impulsivity.     

Intracellular free sodium concentrations in GH4C1 cells

In the present investigation, intracellular sodium ([Na⁺]_i) levels were determined in GH₄C₁ cells using the fluorescent probe SBFI. Fluorescence was determined by excitation at 340 nm and 385 nm, and emission was measured at 500 nm. Intracellular free sodium ([Na⁺]_i) was determined by comparing the ratio 340/385 to a calibration curve. The ratio was linear between 10 and 60 mM Na⁺. Resting [Na⁺]_i in GH₄C₁ cells was 26 ± 6.2 mM (mean ± SD). In cells incubated in Na⁺-buffer [Na⁺]_i decreased to 3 ± 3.6 mM. If Na⁺/K⁺ ATPase was inhibited by incubating the cells with 1 mM ouabain, [Na⁺]_i increased to 47 ± 12.8 mM in 15 min. Stimulating the cells with TRH, phorbol myristyl acetete, or thapsigargin had no effect on [Na⁺]_i. Incubating the cells in Ca²⁺-buffer rapidly increased [Na⁺]_i. The increase was not inhibited by tetrodotoxin. Addition of extracellular Ca²⁺, nimodipine, or Ni²⁺ to these cells immediately decreased [Na⁺]_i, whereas Bay K 8644 enhanced the influx of Na⁺. In cells where [Na⁺]_i was increased the TRH-induced increase in intracellular free calcium ([Ca²⁺]_i) was decreased compared with control cells. Our results suggest that Na⁺ enters the cells via Ca²⁺ channels, and [Na⁺]_i may attenuate TRH-induced changes in [Ca²⁺]_i in GH₄C₁ cells. © 1993 Wiley-Liss, Inc.     

Anthocyanin-enriched bilberry and blackcurrant extracts modulate amyloid precursor protein processing and alleviate behavioral abnormalities in the APP/PS1 mouse model of Alzheimer's disease

A growing body of epidemiological evidence suggests that fruit and vegetable juices containing various phenolic compounds can reduce the risk of Alzheimer's disease (AD). As the altered amyloid precursor protein (APP) processing leading to increased β-amyloid (Aβ) production is a key pathogenic feature of AD, we elucidated the effects of different polyphenols on neuroprotection and APP processing under different in vitro stress conditions. The effects of these compounds were also investigated in transgenic AD mice (APdE9). Free radical toxicity and apoptosis were induced in human SH-SY5Y neuroblastoma cells overexpressing APP751. Menadione-induced production of reactive oxygen species was significantly decreased upon treatment with myricetin, quercetin or anthocyanin-rich extracts in a dose-dependent manner. However, these extracts did not affect caspase-3 activation, APP processing or Aβ levels upon staurosporine-induced apoptosis. APdE9 mice fed with anthocyanin-rich bilberry or blackcurrant extracts showed decreased APP C-terminal fragment levels in the cerebral cortex as compared to APdE9 mice on the control diet. Soluble Aβ40 and Aβ42 levels were significantly decreased in bilberry-fed mice as compared to blackcurrant-fed mice. Conversely, the ratio of insoluble Aβ42/40 was significantly decreased in blackcurrant-fed mice relative to bilberry-fed mice. Both berry diets alleviated the spatial working memory deficit of aged APdE9 mice as compared to mice on the control diet. There were no changes in the expression or phosphorylation status of tau in APdE9 mice with respect to diet. These data suggest that anthocyanin-rich bilberry and blackcurrant diets favorably modulate APP processing and alleviate behavioral abnormalities in a mouse model of AD.     

The effect of explant material on somatic embryogenesis of Cyclamen persicum Mill

Somatic embryos of Cyclamen persicum Mill. could be produced through a callus phase from juvenile explant material including anthers, ovaries and zygotic embryos. The auxin 2,4-D (1.0–1.5 mg l^-1) and coconut milk (10% v/v) in MS medium were important factors for the induction of somatic embryogenesis. Somatic embryos germinated into plantlets in MS medium without growth regulators. The plants grew well in the greenhouse and flowered normally. The plants were phenotypically identical to the mother plants with a few exceptions.Abbreviations 2,4-D 2,4-dichlorophenoxyacetic acid - NAA 1-naphthylacetic acid - IAA 3-indoleacetic acid - BA 6-benzyladenine - ABA abscisic acid - CM coconut milk