Variants of arterial supply to the inferior (diaphragmatic) surface of the ventricles of the heart and the influence on age at death.

Coronary artery systems of the inferior wall of the ventricles vary considerably. Schlesinger's concept distinguishes dominance of the right or left coronary artery (LCA) or balanced type. LCA dominance has been reported to be associated with increased mortality. Early angiography studies have shown that the anterior interventricular artery (AIVA), a branch of the LCA, often continues on the inferior surface of the heart and may replace the inferior interventricular artery. Others considered an AIVA on the inferior surface of the heart a rare variant. A long AIVA is a strong predictor of death in acute anterior wall myocardial infarction. We determined coronary artery variance at the inferior surface of the ventricles in 134 dissected human hearts and analyzed a possible association between coronary artery variance and age at death. The AIVA extended to the inferior side in 64.9% of the hearts, but rarely reached the basal half of the inferior interventricular groove. Most frequently (53%), it extended into the apical two-fifths of the length of the inferior ventricular walls. An AIVA extending to the apical 40% of the length of the inferior ventricular walls may therefore be considered a common variant. In 20.1% of the hearts, a right inferior diagonal artery was also found. Statistical analysis neither revealed an association between mean AIVA length at the inferior ventricular surface and type of coronary artery dominance nor an association between AIVA length at the inferior ventricular surface or coronary artery dominance type and age at death.

The relation between tau pathology and granulovacuolar degeneration of neurons.

Neurofibrillary tangles arising from aggregated microtubule-associated protein tau occur in aged brains and are hallmarks of neurodegenerative diseases. A subset of neurons containing aggregated tau displays granulovacuolar degeneration (GVD) that is characterized by membrane-bound cytoplasmic vacuoles, each containing an electron-dense granule (GVB). Tau pathology induces GVBs in experimental models, but GVD does not generally follow tau pathology in the human brain. The entorhinal cortex, DRN, and LC are among the regions that display pathological changes of tau earliest, whereas neurons with GVBs occur first in the hippocampus and have been found in oral raphe nuclei only at the most advanced GVD stage. To date, there is no detailed report about neurons with GVD in aminergic nuclei. We studied the relation between tau pathology and GVD in field CA1 of the hippocampus, entorhinal cortex, dorsal (DRN) and median (MRN) raphe nucleus, and locus coeruleus from elderly subjects with Braak & Braak stages of tau pathology ranging from 0 to VI. Tau pathology and GVBs were visualized by means of immunolabeling and quantified. Percentages of neurons containing GVBs were significantly related to percentages of AT8-positive neurons in the regions examined. GVD and tau pathology were found together in neurons to a different extent in regions of the brain. 53.2% of AT8-immunoreactive neurons in CA1, 19.8% in layer II of the entorhinal cortex, 29.6% in the DRN, and 31.4% in the locus coeruleus contained GVBs. Age-related factors, the percentage of neurons with pretangles in a region of the brain, and the metabolism of a neuron possibly influence the prevalence of neurons with GVBs.

C-arm flat-panel CT arthrography of the shoulder: Radiation dose considerations and preliminary data on diagnostic performance.

OBJECTIVES: To investigate radiation dose and diagnostic performance of C-arm flat-panel CT (FPCT) versus standard multi-detector CT (MDCT) shoulder arthrography using MRI-arthrography as reference standard. METHODS: Radiation dose of two different FPCT acquisitions (5 and 20 s) and standard MDCT of the shoulder were assessed using phantoms and thermoluminescence dosimetry. FPCT arthrographies were performed in 34 patients (mean age 44 ± 15 years). Different joint structures were quantitatively and qualitatively assessed by two independent radiologists. Inter-reader agreement and diagnostic performance were calculated. RESULTS: Effective radiation dose was markedly lower in FPCT 5 s (0.6 mSv) compared to MDCT (1.7 mSv) and FPCT 20 s (3.4 mSv). Contrast-to-noise ratios (CNRs) were significantly (p < 0.05) higher in FPCT 20-s versus 5-s protocols. Inter-reader agreements of qualitative ratings ranged between к = 0.47-1.0. Sensitivities for cartilage and rotator cuff pathologies were low for FPCT 5-s (40 % and 20 %) and moderate for FPCT 20-s protocols (75 % and 73 %). FPCT showed high sensitivity (81-86 % and 89-99 %) for bone and acromioclavicular-joint pathologies. CONCLUSION: Using a 5-s protocol FPCT shoulder arthrography provides lower radiation dose compared to MDCT but poor sensitivity for cartilage and rotator cuff pathologies. FPCT 20-s protocol is moderately sensitive for cartilage and rotator cuff tendon pathology with markedly higher radiation dose compared to MDCT. KEY POINTS: • FPCT shoulder arthrography is feasible with fluoroscopy and CT in one workflow. • A 5-s FPCT protocol applies a lower radiation dose than MDCT. • A 20-s FPCT protocol is moderately sensitive for cartilage and tendon pathology.

Granulovacuolar degeneration: a neurodegenerative change that accompanies tau pathology.

Granule-containing vacuoles in the cytoplasm of hippocampal neurons are a neuropathological feature of Alzheimer's disease. Granulovacuolar degeneration (GVD) is not disease-specific and can be observed in other neurodegenerative disorders and even in the brains of non-demented elderly people. However, several studies have reported much higher numbers of neurons undergoing GVD in the hippocampus of Alzheimer's disease cases. Recently, a neuropathological staging system for GVD has facilitated neuropathological assessment. Data obtained by electron microscopy and immunolabeling suggest that GVD inclusions are a special form of autophagic vacuole. GVD frequently occurs together with pathological changes of the microtubule-associated protein tau, but to date, the relationship between the two lesions remains elusive. Originally identified in hematoxylin- and silver-stained sections, immunolabeling has shown that the granules are composed of a variety of proteins, including those related to tau pathology, autophagy, diverse signal transduction pathways, cell stress and apoptosis. Several of these proteins serve as markers of GVD. Most researchers and authors have interpreted the sequestration of proteins into GVD inclusions as either a cellular defense mechanism or one that leads to the impairment of important cellular functions. This review provides a detailed overview of the various aspects of GVD and focuses on the relationship between tau pathology and GVD.

Granulovacuolar degeneration and unfolded protein response in mouse models of tauopathy and Aß amyloidosis.

Histopathological studies on the brains of tauopathy cases including cases with Alzheimer's disease (AD) demonstrate that neurons with hyperphosphorylated protein tau display granulovacuolar degeneration (GVD), as evidenced by vacuolar lesions harboring a central granule, together with markers of the activated unfolded protein response (UPR). In order to examine whether this hallmark is reproduced in animal models we studied the presence of GVD and the activated UPR in two complementary mouse models, pR5 mice with a tau pathology and APPSLxPS1mut mice with an amyloid plaque pathology. Neither GVD nor a significant activation of the UPR was found in both APPSLxPS1mut mice and in those regions in the pR5 brain where only neurons with an early stage of tau hyperphosphorylation were present. In contrast, those neurons that displayed a tau phospho-epitope signature that only appeared in old pR5 mice and also correlated with Gallyas-positive tangle staining harbored granulovacuolar lesions that were labeled with the GVD markers casein kinases 1δ and 1ε. Granulovacuolar lesions in pR5 mice were also labeled with the UPR markers phosphorylated PKR-like endoplasmic reticulum kinase, phosphorylated inositol-requiring enzyme 1α and phosphorylated eukaryotic initiation factor 2α. However, GVD was rarely observed in neurons bearing mature neurofibrillary tangles as evidenced by Congo red staining. Our results suggest that NFT-formation activates the UPR in pR5 mice and that it is the early stages of neurofibrillary tangle formation that are accompanied by GVD, in line with observations from studies on human autopsy cases.

Effective dose to patient measurements in flat-detector and multislice computed tomography: a comparison of applications in neuroradiology.

PURPOSE: Flat-detector CT (FD-CT) is used for a variety of applications. Additionally, 3D rotational angiography (3D DSA) is used to supplement digital subtraction angiography (DSA) studies. The aim was to measure and compare the dose of (1) standard DSA and 3D DSA and (2) analogous FD-CT and multislice CT (MSCT) protocols. METHODS: Using an anthropomorphic phantom, the effective dose to patients (according to ICRP 103) was measured on an MSCT and a flat-detector angiographic system using standard protocols as recommended by the manufacturer. RESULTS: (1) Evaluation of DSA and 3D DSA angiography protocols: ap.-lat. Standard/low-dose series 1/0.8 mSv, enlarged oblique projection 0.3 mSv, 3D DSA 0.9 mSv (limited coverage length 0.3 mSv). (2) Comparison of FD-CT and MSCT: brain parenchyma imaging 2.9 /1.4 mSv, perfusion imaging 2.3/4.2 mSv, temporal bone 0.2 /0.2 mSv, angiography 2.9/3.3 mSv, limited to the head using collimation 0.5/0.5 mSv. CONCLUSION: The effective dose for an FD-CT application depends on the application used. Using collimation for FD-CT applications, the dose may be reduced considerably. Due to the low dose of 3D DSA, we recommend using this technique to reduce the number of DSA series needed to identify working projections. KEY POINTS: Effective dose of FD-CT in comparison to MSCT is in comparable range. Collimation decreases the dose of FD-CT effectively. Effective dose of 3-D angiography is identical to 2-D DSA. Different FD-CT programs have different dose.

Effects of P301L-TAU on post-translational modifications of microtubules in human iPSC-derived cortical neurons and TAU transgenic mice.

ABSTRACT: TAU is a microtubule-associated protein that promotes microtubule assembly and stability in the axon. TAU is missorted and aggregated in an array of diseases known as tauopathies. Microtubules are essential for neuronal function and regulated via a complex set of post-translational modifications (PTMs), changes of which affect microtubule stability and dynamics, microtubule interaction with other proteins and cellular structures, and mediate recruitment of microtubule-severing enzymes. As impairment of microtubule dynamics causes neuronal dysfunction, we hypothesize cognitive impairment in human disease to be impacted by impairment of microtubule dynamics. We therefore aimed to study the effects of a disease-causing mutation of TAU (P301L) on the levels and localization of microtubule PTMs indicative of microtubule stability and dynamics, to assess whether P301L-TAU causes stability-changing modifications to microtubules. To investigate TAU localization, phosphorylation, and effects on tubulin PTMs, we expressed wild-type or P301L-TAU in human MAPT-KO induced pluripotent stem cell-derived neurons (iNeurons) and studied TAU in neurons in the hippocampus of mice transgenic for human P301L-TAU (pR5 mice). Human neurons expressing the longest TAU isoform (2N4R) with the P301L mutation showed increased TAU phosphorylation at the AT8, but not the p-Ser-262 epitope, and increased polyglutamylation and acetylation of microtubules compared with endogenous TAU-expressing neurons. P301L-TAU showed pronounced somatodendritic presence, but also successful axonal enrichment and a similar axodendritic distribution comparable to exogenously expressed 2N4R-wildtype-TAU. P301L-TAU-expressing hippocampal neurons in transgenic mice showed prominent missorting and tauopathy-typical AT8-phosphorylation of TAU and increased polyglutamylation, but reduced acetylation, of microtubules compared with non-transgenic littermates. In sum, P301L-TAU results in changes in microtubule PTMs, suggestive of impairment of microtubule stability. This is accompanied by missorting and aggregation of TAU in mice but not in iNeurons. Microtubule PTMs/impairment may be of key importance in tauopathies.

Deficiency of the splicing factor Sfrs10 results in early embryonic lethality in mice and has no impact on full-length SMN/Smn splicing.

The SR-like splicing factor SFRS10 (Htra2-beta1) is well known to influence various alternatively spliced exons without being an essential splicing factor. We have shown earlier that SFRS10 binds SMN1/SMN2 RNA and restores full-length (FL)-SMN2 mRNA levels in vitro. As SMN1 is absent in patients with spinal muscular atrophy (SMA), the level of FL-SMN2 determines the disease severity. Correct splicing of SMN2 can be facilitated by histone deacetylase inhibitors (HDACis) via upregulation of SFRS10. As HDACis are already used in SMA clinical trials, it is crucial to identify the spectrum of alternatively spliced transcripts modulated by SFRS10, because elevated SFRS10 levels may influence or misregulate also other biological processes. To address this issue, we generated a conditional Sfrs10 allele in mice using the Cre/loxP system. The ubiquitous homozygous deletion of Sfrs10, however, resulted in early embryonic lethality around E7.5, indicating an essential role of Sfrs10 during mouse embryogenesis. Deletion of Sfrs10 with recombinant Cre in murine embryonic fibroblasts (MEFs) derived from Sfrs10(fl/fl) embryos increased the low levels of SmnDelta7 3-4-fold, without affecting FL-Smn levels. The weak influence of Sfrs10 on Smn splicing was further proven by a Hb9-Cre driven motor neuron-specific deletion of Sfrs10 in mice, which developed normally without revealing any SMA phenotype. To assess the role of Sfrs10 on FL-SMN2 splicing, we established MEFs from Smn(-/-);SMN2(tg/tg);Sfrs10(fl/fl) embryos. Surprisingly, deletion of Sfrs10 by recombinant Cre showed no impact on SMN2 splicing but increased SMN levels. Our findings highlight the complexity by which alternatively spliced exons are regulated in vivo.

Rapid quantification of tilidine, nortilidine, and bisnortilidine in urine by automated online SPE-LC-MS/MS.

The opioid tilidine is a prodrug which is hepatically metabolized to active nortilidine and bisnortilidine. Due to the increasing abuse of tilidine by drug users and the lack of a specific immunoassay, we developed an analytical method for the quantification of tilidine, nortilidine, and bisnortilidine in urine suitable for screening. In a following step, this method was used to establish data on excretion kinetics of the substances in order to evaluate the time window of detection after a single oral dose of tilidine/naloxone and also was applied to authentic urine samples from correctional facilities. Urine samples were mixed with internal standard solution and extracted on a weak cation exchanger at pH 6 using a Symbiosis Pico system. The chromatographic separation was achieved within a 3.5-min run time on a Phenylhexyl column (50 × 2.0 mm, 5 µm) via gradient elution (methanol and 0.2% formic acid) at a flow rate of 0.50 mL/min. The ESI-MS/MS was performed on a QTrap 3,200 in positive multiple reaction monitoring mode using two mass transitions per analyte. Validating the method resulted in a lower limit of quantification of 1.0 µg/L followed by a linear calibration range to 100 µg/L for each analyte (r(2) > 0.99). The analytical method allowed the detection of a single dose of a commercially available tilidine solution up to 7 days after administration. Using this highly sensitive method, 55 of 3,665 urine samples were tested positive.

Neuronal IGF-1 resistance reduces Abeta accumulation and protects against premature death in a model of Alzheimer's disease.

Alzheimer's disease (AD) is characterized by progressive neurodegeneration leading to loss of cognitive abilities and ultimately to death. Postmortem investigations revealed decreased expression of cerebral insulin-like growth factor (IGF)-1 receptor (IGF-1R) and insulin receptor substrate (IRS) proteins in patients with AD. To elucidate the role of insulin/IGF-1 signaling in AD, we crossed mice expressing the Swedish mutation of amyloid precursor protein (APP(SW), Tg2576 mice) as a model for AD with mice deficient for either IRS-2, neuronal IGF-1R (nIGF-1R(-/-)), or neuronal insulin receptor (nIR(-/-)), and analyzed survival, glucose, and APP metabolism. In the present study, we show that IRS-2 deficiency in Tg2576 mice completely reverses premature mortality in Tg2576 females and delays beta-amyloid (Abeta) accumulation. Analysis of APP metabolism suggested that delayed Abeta accumulation resulted from decreased APP processing. To delineate the upstream signal responsible for IRS-2-mediated disease protection, we analyzed mice with nIGF-1R or nIR deficiency predominantly in the hippocampus. Interestingly, both male and female nIGF-1R(-/-)Tg2576 mice were protected from premature death in the presence of decreased Abeta accumulation specifically in the hippocampus formation. However, neuronal IR deletion had no influence on lethality of Tg2576 mice. Thus, impaired IGF-1/IRS-2 signaling prevents premature death and delays amyloid accumulation in a model of AD.

Aggregates of RNA Binding Proteins and ER Chaperones Linked to Exosomes in Granulovacuolar Degeneration of the Alzheimer's Disease Brain.

Granulovacuolar degeneration (GVD) occurs in Alzheimer's disease (AD) brain due to compromised autophagy. Endoplasmic reticulum (ER) function and RNA binding protein (RBP) homeostasis regulate autophagy. We observed that the ER chaperones Glucose - regulated protein, 78 KDa (GRP78/BiP), Sigma receptor 1 (SigR1), and Vesicle-associated membrane protein associated protein B (VAPB) were elevated in many AD patients' subicular neurons. However, those neurons which were affected by GVD showed lower chaperone levels, and there was only minor co-localization of chaperones with GVD bodies (GVBs), suggesting that neurons lacking sufficient chaperone-mediated proteostasis enter the GVD pathway. Consistent with this notion, granular, incipient pTau aggregates in human AD and pR5 tau transgenic mouse neurons were regularly co-localized with increased chaperone immunoreactivity, whereas neurons with mature neurofibrillary tangles lacked both the chaperone buildup and significant GVD. On the other hand, APP/PS1 (APPswe/PSEN1dE9) transgenic mouse hippocampal neurons that are devoid of pTau accumulation displayed only few GVBs-like vesicles, which were still accompanied by prominent chaperone buildup. Identifying a potential trigger for GVD, we found cytoplasmic accumulations of RBPs including Matrin 3 and FUS as well as stress granules in GVBs of AD patient and pR5 mouse neurons. Interestingly, we observed that GVBs containing aggregated pTau and pTDP-43 were consistently co-localized with the exosomal marker Flotillin 1 in both AD and pR5 mice. In contrast, intraneuronal 82E1-immunoreactive amyloid-ß in human AD and APP/PS1 mice only rarely co-localized with Flotillin 1-positive exosomal vesicles. We conclude that altered chaperone-mediated ER protein homeostasis and impaired autophagy manifesting in GVD are linked to both pTau and RBP accumulation and that some GVBs might be targeted to exocytosis.

Effect of tau-pathology on charged multivesicular body protein 2b (CHMP2B).

Charged multivesicular body protein 2b (CHMP2B) is a subunit of the endosomal sorting complex required for transport (ESCRT)-III that mediates scission of budded membranes. Neurons with CHMP2B-positive granulovacuolar inclusions in the cytoplasm are much more frequent in hippocampi of cases with Alzheimer's disease when compared with controls. We analyzed immunolabeled brain sections from tau-transgenic mice, APP-transgenic mice, non-transgenic mice, and human hippocampi to investigate the relation between CHMP2B and tau and plaque pathology that are major histopathological features of Alzheimer's disease. Neurons undergoing granulovacuolar degeneration (GVD) were found in human hippocampi and old tau-trangenic mice but not in the APP-transgenic strains. 57% of neurons with GVD displayed GVD-granules double-labeled for CHMP2B and the GVD-marker casein kinase 1δ in 24 months-old tau-transgenic mice and 5.7% of neurons with tau hyper-phosphorylated at Thr212 and Ser214 (immunoreactive with antibody AT100) displayed CHMP2B-positive GVD-granules, in human hippocampi it was 100% and 46% respectively. The number of neurons with GVD-inclusions increased in tau-transgenic mice with the number of AT100-positive neurons, suggesting a link between tau-pathology and GVD. GVD-granules in human hippocampi also displayed immunoreactivity for Vps4a, another protein component of ESCRT-III. In cases with aging-related tau astrogliopathy (ARTAG), astrocytes containing hyper-phosphorylated tau immunoreactive with antibody AT8 displayed strong CHMP2B immunoreactivity. The results suggest dysregulation of CHMP2B together with tau-pathology and possibly a disturbance of the regulation of vesicular compartments. The absence of combined Aß- and tau-associated pathology in the transgenic mice may account for the difference in CHMP2B-immunoreactivity between the transgenic mice and human hippocampus.

IRS-2 branch of IGF-1 receptor signaling is essential for appropriate timing of myelination.

Insulin-like growth factor (IGF)-1 increases proliferation, inhibits apoptosis and promotes differentiation of oligodendrocytes and their precursor cells, indicating an important function for IGF-1 receptor (IGF-1R) signaling in myelin development. The insulin receptor substrates (IRS), IRS-1 and -2 serve as intracellular IGF-1R adaptor proteins and are expressed in neurons, oligodendrocytes and their precursors. To address the role of IRS-2 in myelination, we analyzed myelination in IRS-2 deficient (IRS-2(-/-)) mice and age-matched controls during postnatal development. Interestingly, expression of the most abundant myelin proteins, myelin basic protein and proteolipid protein was reduced in IRS-2(-/-) brains at postnatal day 10 (P10) as compared to controls. myelin basic protein immunostaining in P10-IRS-2(-/-) mice revealed a reduced immunostaining, but an unchanged regional distribution pattern. In cerebral myelin isolates at P10 unaltered relative expression of different myelin proteins was found, indicating quantitatively reduced but not qualitatively altered myelination. Interestingly, up-regulation of IRS-1 expression and increased IGF-1R signaling were observed in IRS-2(-/-) mice at P10-14, indicating a compensatory mechanism to overcome IRS-2 deficiency. Adult IRS-2(-/-) mice showed unaltered myelination and motor function. Furthermore, in neuronal/brain-specific insulin receptor knockout mice myelination was unchanged. Thus, our experiments reveal that IGF-1R/IRS-2 mediated signals are critical for appropriate timing of myelination in vivo.

Analysis of ribosomal protein S6 baseline phosphorylation and effect of tau pathology in the murine brain and human hippocampus.

We examined the distribution pattern of the phosphorylated 40S ribosomal subunit protein S6, a downstream target of the mTOR pathway, in the brains of 24-months-old human tau transgenic pR5 mice, non-transgenic littermates and in human hippocampi. We studied baseline levels of phosphorylated S6 and a possible effect of tau pathology. S6 phosphorylated at Ser235/236 (pS6Ser235/236) or Ser240/244 (pS6Ser240/244) has been used as a read-out of mTOR activity in several studies. The mTOR pathway regulates a wide variety of cellular functions including cell growth, ribosome biosynthesis, translational control and autophagy. Its dysregulation might underlie the neurodegenerative pathology of Alzheimer's disease and other tauopathies. pS6Ser235/236 and pS6Ser240/244 immunoreactivity in the mouse brain were widespread and similar distributed, but intensive pS6Ser235/236 immunoreactivity was more selective, especially highlighting certain brainstem regions. In the human hippocampus mainly granulovacuolar inclusions in neurons displayed pS6Ser235/236 immunoreactivity. In contrast, a considerable number of neurons displayed pS6Ser240/244 immunoreactivity in the cytoplasm without labeling of granulovacuolar inclusions. Except for a tendency of lower numbers of intensely phosphorylated S6-positive neurons in pR5 mice, the pattern of distribution of pS6Ser235/236 and pS6Ser240/244 immunoreactivity was largely unchanged when compared with non-transgenic mice and also when human hippocampi from AD cases and controls were compared. Similar to pR5 mice most neurons with hyper-phosphorylated tau in human hippocampi displayed no or only weak labeling for phosphorylated S6, suggesting that phosphorylated S6 is not especially associated with pathological tau, but is rather a feature of unaffected neurons.

Distribution of spleen tyrosine kinase and tau phosphorylated at tyrosine 18 in a mouse model of tauopathy and in the human hippocampus.

PURPOSE: Spleen tyrosine kinase (Syk) has been shown to phosphorylate tyrosine 18 of tau in vitro. It has been proposed that increased immunoreactivity for double-phosphorylated Syk in hippocampal neurons of Alzheimer's disease cases indicates a not yet defined neurodegenerative process. To investigate this possibility we have studied Syk and tau phosphorylated at tyrosine 18 (pTyr18) in transgenic mice and human hippocampi. METHODS: We performed immunohistochemistry, immunofluorescence labeling and Western blotting and compared the distribution of Syk double-phosphorylated at tyrosines 525 and 526 and pTyr18 in human tau transgenic pR5 mice and human hippocampi with low and high Braak stages for neurofibrillary tangle pathology. RESULTS: pTyr18 appeared early during the course of neurodegeneration in pR5 mice and was widely distributed in the pR5 brain, including neuronal somata and fiber tracts. In contrast, only strongly pTyr18- and AT100-(tau phosphorylated at Thr212 and Ser214) positive neurons with a fibrillary tau pathology in old pR5 mice and microglia displayed immunoreactivity for double-phosphorylated Syk. In human hippocampi, phosphorylated Syk was mainly present in granulovacuolar inclusions in hippocampal pyramidal neurons and did not co-locate with pTyr18 in these neurons. We observed pTyr18-positive neurons and neurons with granular pSyk immunoreactivity already at early Braak stages and their number was markedly increased in Braak stage VI. CONCLUSION: Syk appears unlikely to be the major kinase that phosphorylates tyrosine 18 of tau in tauopathy. It possibly phosphorylates tyrosine 18 of tau and regulates other tau kinases in neurons with a fibrillary tau pathology.

Vascular oxidative stress and endothelial dysfunction in patients with chronic heart failure: role of xanthine-oxidase and extracellular superoxide dismutase.

BACKGROUND: Impaired flow-dependent, endothelium-mediated vasodilation (FDD) in patients with chronic heart failure (CHF) results, at least in part, from accelerated degradation of nitric oxide by oxygen radicals. The mechanisms leading to increased vascular radical formation, however, remain unclear. Therefore, we determined endothelium-bound activities of extracellular superoxide dismutase (ecSOD), a major vascular antioxidant enzyme, and xanthine-oxidase, a potent radical producing enzyme, and their relation to FDD in patients with CHF. METHODS AND RESULTS: ecSOD and xanthine-oxidase activities, released from endothelium into plasma by heparin bolus injection, were determined in 14 patients with CHF and 10 control subjects. FDD of the radial artery was measured using high-resolution ultrasound and was assessed before and after administration of the antioxidant vitamin C (25 mg/min; IA). In patients with CHF, endothelium-bound ecSOD activity was substantially reduced (5.0+/-0.7 versus 14.4+/-2.6 U x mL(-1) x min(-1); P<0.01) and closely related to FDD (r=0.61). Endothelium-bound xanthine-oxidase activity was increased by >200% (38+/-10 versus 12+/-4 nmol O2*- x microL(-1); P<0.05) and inversely related to FDD (r=-0.35) in patients with CHF. In patients with low ecSOD and high xanthine-oxidase activity, a greater benefit of vitamin C on FDD was observed, ie, the portion of FDD inhibited by radicals correlated negatively with ecSOD (r=-0.71) but positively with xanthine-oxidase (r=0.75). CONCLUSIONS: These results demonstrate that both increased xanthine-oxidase and reduced ecSOD activity are closely associated with increased vascular oxidative stress in patients with CHF. This loss of vascular oxidative balance likely represents a novel mechanism contributing to endothelial dysfunction in CHF.

Axially extended-volume C-arm CT using a reverse helical trajectory in the interventional room.

C-arm computed tomography (CT) is an innovative technique that enables a C-arm system to generate 3-D images from a set of 2-D X-ray projections. This technique can reduce treatment-related complications and may improve interventional efficacy and safety. However, state-of-the-art C-arm systems rely on a circular short scan for data acquisition, which limits coverage in the axial direction. This limitation was reported as a problem in hepatic vascular interventions. To solve this problem, as well as to further extend the value of C-arm CT, axially extended-volume C-arm CT is needed. For example, such an extension would enable imaging the full aorta, the peripheral arteries or the spine in the interventional room, which is currently not feasible. In this paper, we demonstrate that performing long object imaging using a reverse helix is feasible in the interventional room. This demonstration involved developing a novel calibration method, assessing geometric repeatability, implementing a reconstruction method that applies to real reverse helical data, and quantitatively evaluating image quality. Our results show that: 1) the reverse helical trajectory can be implemented and reliably repeated on a multiaxis C-arm system; and 2) a long volume can be reconstructed with satisfactory image quality using reverse helical data.

Active glycogen synthase kinase-3 and tau pathology-related tyrosine phosphorylation in pR5 human tau transgenic mice.

We studied underlying pathomechanisms in tauopathies using pR5 mice that express the P301L tau mutation found in familial forms of frontotemporal dementia. In a longitudinal study we investigated the functional status of glycogen synthase kinase-3 and correlated it with the appearance of distinct tau phospho-epitopes. Neurons displaying increases in activating phosphorylation of glycogen synthase kinase-3α/ß at tyrosine 279/216 also showed an intense rather than moderate AT8 (phospho-Ser202/Thr205 tau) immunoreactivity, and immunoreactivity for AT100 (phospho-Ser212/Thr214 tau) and phosphorylated Ser422, phospho-epitopes associated with fibrillar tau pathology. These neurons were rare in 8.5-month-old, but numerous in 18.5- and 28-month-old pR5 mice. Two antibodies that detect phosphotyrosine residues more generally only stained these neurons. In contrast, we did not find increased phosphotyrosine in neuronal perikarya of mice with an amyloid-ß plaque pathology. Our results suggest a link between increased tyrosine phosphorylation and tau aggregation. They also reveal for the mouse models studied, that tau- rather than an amyloid-ß peptide-induced pathology is associated with increased neuronal tyrosine phosphorylation.

Pattern of tau hyperphosphorylation and neurotransmitter markers in the brainstem of senescent tau filament forming transgenic mice.

The early occurrence of brainstem-related symptoms, e.g. gait and balance impairment, apathy and depression in Alzheimer's disease patients suggests brainstem involvement in the initial pathogenesis. To address the question whether tau filament forming mice expressing mutated human tau mirror histopathological changes observed in Alzheimer brainstem, the degree and distribution of neurofibrillary lesions as well as the pattern of cholinergic and monoaminergic neurons were investigated. The expression of the human tau transgene was observed in multiple brainstem nuclei, particularly in the magnocellular reticular formation, vestibular nuclei, cranial nerve motor nuclei, sensory trigeminal nerve nuclei, inferior and superior colliculi, periaqueductal and pontine gray matter, and the red nucleus. Most of the human tau-immunoreactive cell groups also showed tau hyperphosphorylation at the epitopes Thr231/Ser235 and Ser202/Thr205, while abnormal tau phosphorylation at the epitope Ser422 or silver stained structures were almost totally lacking. We found no obvious differences in distribution and density of cholinergic and monoaminergic neurons between tau-transgenic and wild type mice. Although numerous brainstem nuclei in our model expressed human tau protein, the development of neurofibrillary tangles, neuropil threads and ghost tangles was rare and likewise its distribution differed largely from Alzheimer's disease pattern. The number of monoaminergic neurons remained unchanged in the transgenic mice, while monoaminergic nuclei in Alzheimer brainstem showed a distinct neuronal loss. However, the distribution of pretangle-affected neurons in the tau-transgenic mice partly resembled those seen in progressive supranuclear palsy, presenting these animals as a model to examine brainstem pathogenesis of progressive supranuclear palsy.