Microarray-based analysis of gene expression in very large gene families: the cytochrome P450 gene superfamily of Arabidopsis thaliana

Cytochrome P450 (P450s) are heme-thiolate protein products of a very large gene superfamily, present in all kingdoms and involved in a variety of metabolic reactions. P450s are classified according to the degree of amino acid sequence identity, with P450s of the same family defined as having >40% identity, and P450s of the same subfamily having >55% identity. Currently, 273 P450 genes distributed over 45 families have been identified in Arabidopsis, and its genome is estimated to contain as many as 286. Genome-wide DNA microarrays make it possible to broadly correlate P450 gene activity with alterations in physiological or developmental states. A potential problem with microarray research is that sequence similarity between and within these families of closely related genes may lead to cross-hybridization. We designed experiments to systematically evaluate the specificity of P450 microarrays, and showed that conditions could be optimized to provide a very high degree of hybridization specificity. Under these conditions, and employing a 20% intensity value of maximum hybridization intensity as a cut-off, labeled P450 genes exhibited essentially no cross-hybridization between families and within subfamilies. We also compared the gene transcription levels of microarray probes derived from EST clones and from genomic DNA sequences for which ESTs were not available, using cDNA produced from RNA from various Arabidopsis tissue as the target. Many of the P450 genes displayed tissue-specific expression, leading to hypotheses as to the function of individual genes and their regulation. We also observed that several of the genomic sequences reported high levels of expression, highlighting the limitations of expression analysis based on ESTs alone.

MRI abnormalities in Creutzfeldt-Jakob disease

Two patients with biopsy-proven Creutzfeldt-Jakob disease had MRI studies that revealed increased signal in the basal ganglia on T-2 weighted images, suggesting that MRI can be a useful diagnostic instrument in Creutzfeldt-Jakob disease.

Pressor and depressor responses in thermocoagulation of the trigeminal ganglion

We have undertaken a retrospective analysis in 126 patients with trigeminal neuralgia on which a free-hand percutaneous thermocoagulation of the Gasserian ganglion was performed in our department. We focused on the occurrence of intraoperative vagal reactions, i.e. significant bradycardia and changes in blood pressure during the course of the procedure. Operative and anaesthetic records of patients who underwent the procedure were evaluated and correlated with clinical data from the patient's history. We observed the occurrence of vagal reactions i.e. significant bradycardia (< 50/min) or syncope in 20% of patients (p < 0.0002) during or immediately after penetration of the foramen ovale. No correlation between the operated side and the occurrence of vagal reactions was found. A significant rise in blood pressure levels (about 180 mmHg systolic) was observed in 36% of patients during thermocoagulation. We concluded that painful stimuli arising from lesioning in the course of the trigeminal nerve reach the mid-brain and may irritate the dorsal nucleus of the vagus nerve resulting in significant bradycardia or cardiac synode. To prevent haemodynamic deterioration i.v. atropine (0.5-2 mg) should be available when advancing the needle, while anti-hypertensive medication (Esmolol) may be needed during coagulation.

Phase I-II trial of aclacinomycin A given in a four-consecutive-day schedule to patients with solid tumours. A South-East European Oncology Group (SEEOG) Study

Aclacinomycin A (ACM) in a daily dose of 30 mg/m2 was infused over 1 h on 4 consecutive days to 50 patients. Myelotoxicity was acceptable, nausea and vomiting was frequent, hair loss was mild. Grade 1-2 cardiac rhythm abnormalities were observed in 12% of the patients. Between days 1 and 4 the heart rate and the corrected Q-T interval increased while the amplitude of the T wave decreased significantly, cardiac contractility remained unchanged. In 24 evaluable breast cancer patients 1 complete remission (4%) and 2 partial remissions (8%) lasting for only 2-3 months were seen. None of the 8 patients suffering from ovarial cancer benefitted from ACM therapy.

Verhaltenssymptome bei Demenz in Pflegeeinrichtungen

In fortgeschrittenen Stadien von Demenzerkrankungen treten neben Depression vermehrt Verhaltenssymptome auf, zu denen Unruhe, Aggressivität und Halluzinationen zählen. In Pflegeeinrichtungen betrifft dies bis zu drei Viertel aller Bewohner. Diese Symptome sind für Pflegende belastend, ziehen erhöhte Versorgungskosten, eine vermehrte Verschreibung von Psychopharmaka, sowie häufigere Krankenhausaufenthalte nach sich. Im Jahr 2003 haben die Amerikanischen Gesellschaften für Gerontopsychiatrie und Geriatrie Leitlinien zur Behandlung von Depressionen und Verhaltenssymptomen in Pflegeeinrichtungen vorgestellt. Vergleichbare Leitlinien der deutschen Fachgesellschaften liegen bislang nicht vor. Die amerikanischen Leitlinien geben neben einem standardisierten Assessment Therapiealgorhythmen vor. In unserem Projekt werden diese Leitlinien in acht Pflegeinrichtungen in Berlin eingeführt und die Ausprägung von Verhaltenssymptomen, die Verschreibung von Psychopharmaka, die Anzahl der Krankenhauseinweisungen und die Belastung der Pflegenden mit einer Kontrollstichprobe von acht vergleichbaren Pflegeeinrichtungen ohne Leitlinienbehandlung über einen Zeitraum von 12 Monaten verglichen. Wir erwarten eine Verminderung der Ausprägung von Verhaltenssymptomen, sowie der Psychopharmakaverschreibungen, der Hospitalisierungsrate und der subjektiven Belastung für Pflegende.

Human brain clearance imaging: Pathways taken by magnetic resonance imaging contrast agents after administration in cerebrospinal fluid and blood

Over the last decade, it has become evident that cerebrospinal fluid (CSF) plays a pivotal role in brain solute clearance through perivascular pathways and interactions between the brain and meningeal lymphatic vessels. Whereas most of this fundamental knowledge was gained from rodent models, human brain clearance imaging has provided important insights into the human system and highlighted the existence of important interspecies differences. Current gold standard techniques for human brain clearance imaging involve the injection of gadolinium-based contrast agents and monitoring their distribution and clearance over a period from a few hours up to 2 days. With both intrathecal and intravenous injections being used, which each have their own specific routes of distribution and thus clearance of contrast agent, a clear understanding of the kinetics associated with both approaches, and especially the differences between them, is needed to properly interpret the results. Because it is known that intrathecally injected contrast agent reaches the blood, albeit in small concentrations, and that similarly some of the intravenously injected agent can be detected in CSF, both pathways are connected and will, in theory, reach the same compartments. However, because of clear differences in relative enhancement patterns, both injection approaches will result in varying sensitivities for assessment of different subparts of the brain clearance system. In this opinion review article, the "EU Joint Programme - Neurodegenerative Disease Research (JPND)" consortium on human brain clearance imaging provides an overview of contrast agent pharmacokinetics in vivo following intrathecal and intravenous injections and what typical concentrations and concentration-time curves should be expected. This can be the basis for optimizing and interpreting contrast-enhanced MRI for brain clearance imaging. Furthermore, this can shed light on how molecules may exchange between blood, brain, and CSF.

Cargo-less Nanoparticles Prevent Bone Loss in Periodontitis and Peri-implantitis

Periodontal and peri-implant diseases are a significant public health problem worldwide, resulting in the destruction of the supporting bone. These bone defects can cause esthetic problems, increased relapse rate, and eventually tooth loss. The etiology of periodontal disease involves an influx of innate immune cells (neutrophils and monocytes) and upregulation of local inflammatory cytokines in the gingiva. Biodegradable polymeric nanoparticles are an inexpensive, safe, and effective means of preventing innate immune activation by bacterial biofilms. We therefore hypothesize that this technology is a potential means of managing periodontal disease. Polylactic acid (PLA) particles were fabricated using an oil-in-water emulsion and used as a therapy in ligature-induced periodontitis and peri-implantitis. Mice were treated daily with nanoparticles or saline control through intravenous injection for 5 or 7 d. Bone loss and quality were characterized using micro-computed tomography and histology, and immune cell infiltrate was characterized by flow cytometry and enzyme-linked immunosorbent assay. PLA particle therapy prevented bone loss in both periodontitis and peri-implantitis. Particle treatment was associated with decreased osteoclast activation. Flow cytometry showed particles were mainly taken up by macrophages and limited inflammatory monocyte recruitment to the ligature site. In vitro evaluation of particle therapy demonstrated the inhibition of toll-like receptor activation during particle treatment. These results extended to monocytes that had been presensitized by titania nanoparticles. Taken together, the results of these experiments demonstrated that cargo-less PLA particle therapy may be a safe, cost-effective therapy to manage inflammatory bone loss in periodontal disease.

Method Modification (2004.08) to Field Testing of Visible Powders on a Variety of Nonporous Environmental Surfaces: Field Study

The RAMP® Anthrax Test Cartridge for detecting Bacillus anthracis was validated for use in the field for detection of B. anthracis spores in visible powder residues on 7 nonporous environmental surfaces. Six teams of trained first responders and civil support personnel in Class C personal protective equipment sampled visible powder residues on plastic, stainless steel, ceramic tile, wood, rubber, sealed concrete, and food-grade painted wood and analyzed the samples on the RAMP Anthrax Test System. The accuracy for each surface was at least 97% and the overall average was 98.8%. The overall average false-positive rate was 1.79% and false-negative rate was 1.07% for all surfaces. There were no significant differences between surfaces or between spore levels.

Machine Learning-Based Perivascular Space Volumetry in Alzheimer Disease

OBJECTIVES

Impaired perivascular clearance has been suggested as a contributing factor to the pathogenesis of Alzheimer disease (AD). However, it remains unresolved when the anatomy of the perivascular space (PVS) is altered during AD progression. Therefore, this study investigates the association between PVS volume and AD progression in cognitively unimpaired (CU) individuals, both with and without subjective cognitive decline (SCD), and in those clinically diagnosed with mild cognitive impairment (MCI) or mild AD.

MATERIALS AND METHODS

A convolutional neural network was trained using manually corrected, filter-based segmentations (n = 1000) to automatically segment the PVS in the centrum semiovale from interpolated, coronal T2-weighted magnetic resonance imaging scans (n = 894). These scans were sourced from the national German Center for Neurodegenerative Diseases Longitudinal Cognitive Impairment and Dementia Study. Convolutional neural network-based segmentations and those performed by a human rater were compared in terms of segmentation volume, identified PVS clusters, as well as Dice score. The comparison revealed good segmentation quality (Pearson correlation coefficient r = 0.70 with P < 0.0001 for PVS volume, detection rate in cluster analysis = 84.3%, and Dice score = 59.0%). Subsequent multivariate linear regression analysis, adjusted for participants' age, was performed to correlate PVS volume with clinical diagnoses, disease progression, cerebrospinal fluid biomarkers, lifestyle factors, and cognitive function. Cognitive function was assessed using the Mini-Mental State Examination, the Comprehensive Neuropsychological Test Battery, and the Cognitive Subscale of the 13-Item Alzheimer's Disease Assessment Scale.

RESULTS

Multivariate analysis, adjusted for age, revealed that participants with AD and MCI, but not those with SCD, had significantly higher PVS volumes compared with CU participants without SCD ( P = 0.001 for each group). Furthermore, CU participants who developed incident MCI within 4.5 years after the baseline assessment showed significantly higher PVS volumes at baseline compared with those who did not progress to MCI ( P = 0.03). Cognitive function was negatively correlated with PVS volume across all participant groups ( P ≤ 0.005 for each). No significant correlation was found between PVS volume and any of the following parameters: cerebrospinal fluid biomarkers, sleep quality, body mass index, nicotine consumption, or alcohol abuse.

CONCLUSIONS

The very early changes of PVS volume may suggest that alterations in PVS function are involved in the pathophysiology of AD. Overall, the volumetric assessment of centrum semiovale PVS represents a very early imaging biomarker for AD.

[Mechanics of palatal expansion in the occlusal plane]

The mechanics of a transpalatal arch in the occlusal plane (symmetrical V-bends, asymmetrical V-bends and step-bends) is studied through four methods: simulation of the teeth movements with a typodont, measure of the forces and the moments with a mechanical system composed of pulleys and dead load devices, photo-elastic stress analysis, finite element stress analysis. Typodont experimentations display the dental movements: the easiest one is rotation; it is more difficult to observe distalization and mesialisation that occur with a version of the tooth. An experimental apparatus, composed of pulleys and dead load devices, allows to measure forces and moments released by a transpalatal arch, depending on the level of the activations. The authors notice that the distalization force for an asymmetrical V-bend activation is low, about 0.2 Newton for 5 degrees of activation. Photo-elastic stress analysis affords a visualization of the shear stresses induced by a transpalatal arch within the supporting structures of a root, thanks to the observation of colored fringes in a model constituted with two molars included in a birefringent resin. Meanwhile, the manipulation of the photo-elastic resin is not easy and the interpretation of the results remains difficult. The finite element method is a numerical analysis and consists in the fragmentation of the studied structure in a certain number of elements, where forces and moments can be applied: the three dimensional program analyses the stress and strains in these elements. Thus, we can: 1.--visualize strains and stresses of a transpalatal arch, when it is inserted in the lingual molar sheaths; 2.--observe the dental movements due to the activations of the transpalatal arch (rotation, version, mesialisation, distalization); 3.--study the stress induced in the periodontal tissue. The results of these studies are complementary and in agreement. Particularly, the second method (measure of forces and moments) and the finite element method provide a mathematical and visual model that could explain clinical results: thus, the main purpose of this research is to understand the orthodontic mechanics used in the edgewise or segmented technique.