RNA degradation differentially affects quantitative mRNA measurements of endogenous reference genes in human placenta

It has been highlighted that RNA quality and appropriate reference gene selection is crucial for the interpretation of RT-qPCR results in human placental samples. In this context we investigated the effect of RNA degradation on the mRNA abundance of seven frequently used reference genes in 119 human placental samples. Combining RNA integrity measurements, RT-qPCR analysis and mathematical modeling we found major differences regarding the effect of RNA degradation on the measured expression levels between the different reference genes. Furthermore, we demonstrated that a modified RNA extraction method significantly improved RNA quality and consequently increased transcript levels of all reference genes.

Increased placental phospholipid levels in pre-eclamptic pregnancies

Physiological pregnancy is associated with an increase in lipids from the first to the third trimester. This is a highly regulated response to satisfy energy and membrane demands of the developing fetus. Pregnancy disorders, such as pre-eclampsia, are associated with a dysregulation of lipid metabolism manifesting in increased maternal plasma lipid levels. In fetal placental tissue, only scarce information on the lipid profile is available, and data for gestational diseases are lacking. In the present study, we investigated the placental lipid content in control versus pre-eclamptic samples, with the focus on tissue phospholipid levels and composition. We found an increase in total phospholipid content as well as changes in individual phospholipid classes in pre-eclamptic placental tissues compared to controls. These alterations could be a source of placental pathological changes in pre-eclampsia, such as lipid peroxide insult or dysregulation of lipid transport across the syncytiotrophoblast.

Sodium/hydrogen exchanger NHA2 is critical for insulin secretion in β-cells

NHA2 is a sodium/hydrogen exchanger with unknown physiological function. Here we show that NHA2 is present in rodent and human β-cells, as well as β-cell lines. In vivo, two different strains of NHA2-deficient mice displayed a pathological glucose tolerance with impaired insulin secretion but normal peripheral insulin sensitivity. In vitro, islets of NHA2-deficient and heterozygous mice, NHA2-depleted Min6 cells, or islets treated with an NHA2 inhibitor exhibited reduced sulfonylurea- and secretagogue-induced insulin secretion. The secretory deficit could be rescued by overexpression of a wild-type, but not a functionally dead, NHA2 transporter. NHA2 deficiency did not affect insulin synthesis or maturation and had no impact on basal or glucose-induced intracellular Ca(2+) homeostasis in islets. Subcellular fractionation and imaging studies demonstrated that NHA2 resides in transferrin-positive endosomes and synaptic-like microvesicles but not in insulin-containing large dense core vesicles in β-cells. Loss of NHA2 inhibited clathrin-dependent, but not clathrin-independent, endocytosis in Min6 and primary β-cells, suggesting defective endo-exocytosis coupling as the underlying mechanism for the secretory deficit. Collectively, our in vitro and in vivo studies reveal the sodium/proton exchanger NHA2 as a critical player for insulin secretion in the β-cell. In addition, our study sheds light on the biological function of a member of this recently cloned family of transporters.

The sodium-dependent ascorbic acid transporter family SLC23

Transporters for vitamin C and its oxidized form dehydroascorbic acid (DHA) are crucial to maintain physiological concentrations of this important vitamin that is used in a variety of biochemical processes. The human SLC23 family consists of the Na(+)-dependent vitamin C transporters SVCT1 (encoded by the SLC23A1 gene) and SVCT2 (SLC23A2) as well as an orphan transporter SVCT3 (SLC23A3). Phylogenetically, the SLC23 family belongs to the nucleobase-ascorbate transporter (NAT) family, although no nucleobase transport has yet been demonstrated for the human members of this family. The SVCT1 and SVCT2 transporters are rather specific for ascorbic acid, which is an important antioxidant and plays a crucial role in a many metal-containing enzymes. SVCT1 is expressed predominantly in epithelial tissues such as intestine where it contributes to the supply and maintenance of whole-body ascorbic acid levels. In contrast to various other mammals, humans are not capable of synthesizing ascorbic acid from glucose and therefore the uptake of ascorbic acid from the diet via SVCT1 is essential for maintaining appropriate concentrations of vitamin C in the human body. The expression of SVCT2 is relatively widespread, where it serves to either deliver ascorbic acid to tissues with high demand of the vitamin for enzymatic reactions or to protect metabolically highly active cells or specialized tissues from oxidative stress. The murine Slc23a3 gene encoding the orphan transporter SVCT3 was originally cloned from mouse yolk sac, and subsequent studies showed that it is expressed in the kidney. However, the function of SVCT3 has not been reported and it remains speculative as to whether SVCT3 is a nucleobase transporter.

AopP, a type III effector protein of Aeromonas salmonicida, inhibits the NF-kappaB signalling pathway

Aeromonas salmonicida subsp. salmonicida contains a functional type III secretion system that is responsible for the secretion of the ADP-ribosylating toxin AexT. In this study, the authors identified AopP as a second effector protein secreted by this system. The aopP gene was detected in both typical and atypical A. salmonicida isolates and was found to be encoded on a small plasmid of approximately 6.4 kb. Sequence analysis indicates that AopP is a member of the YopJ family of effector proteins, a group of proteins that interfere with mitogen-activated protein kinase (MAPK) and/or nuclear factor kappa B (NF-kappaB) signalling pathways. AopP inhibits the NF-kappaB pathway downstream of IkappaB kinase (IKK) activation, while a catalytically inactivated mutant, AopPC177A, does not possess this inhibitory effect. Unlike other effectors of the YopJ family, such as YopJ and VopA, AopP does not inhibit the MAPK signalling pathway.

Dysphagia in elderly women: consider tetanus

BACKGROUND: Dysphagia is seldom caused by tetanus; however, it is a common symptom of tetanus. Treating patients with tetanus is a rare event in industrialized countries and awareness is needed to recognize early signs of this serious disease. In Switzerland, the most recently reported tetanus cases occurred in elderly women with insufficient seroprotection. PATIENTS: We report on three elderly women presenting with dysphagia as an initial symptom of tetanus. RESULTS: Generalized tetanus was diagnosed in two patients upon admission, the third presented with cephalic tetanus with secondary generalization. All three patients had undetectable levels of tetanus antibodies and had no documented prior tetanus immunizations. Cultures of wound swabs grew Clostridium tetani in all cases. Electromyography was highly suggestive for tetanus in two patients. Treatment involved mechanical ventilation, intravenous benzodiazepine and metronidazole therapy, and active and passive tetanus immunization. The disease had a favorable outcome in two cases and was fatal in one. CONCLUSION: Tetanus remains a threat in patients with insufficient seroprotection and efforts are needed to improve tetanus immunization in these individuals. Tetanus should be considered in the differential diagnosis of dysphagia.

Oral mucosal lesions diagnosed in a stomatology service. An examination of clinico-pathological findings from the year 2003

During 2003, a total of 258 new patients with oral soft tissue lesions were admitted at the Stomatology Service of the Department of Oral Surgery and Stomatology at the University of Berne. For the present study, 185 patients with clinically and histopathologically verified diagnoses were included. The following data was collected: prevalence of oral mucosal lesions, distribution of benign, precancerous and malign lesions in different age groups, and the concordance of the referral with the working diagnosis at the Stomatology Service. The most frequent pathological soft tissue findings were fibrous hyperplasias (n = 44) and oral lichen planus (n = 30). Precancerous lesions were present in 41 cases (30 patients with oral lichen planus, eleven oral leukoplakias), and ten patients had oral malignomas. Most lesions were found in patients between the age of 40 and 60 years. The referral diagnosis concurred in 36.6% (n = 67) of the cases with the definite diagnosis before initiation of treatment, the working diagnosis in 70% (n = 128) of the cases. Therefore, it can be concluded that a specialised Stomatology Service serves as a center of competence due to large numbers of patients/cases seen and treated, and the resulting high level of clinical experience of the staff. Moreover, it is important in the primary diagnosis of oral squamous cell carcinoma, in collaboration with the referring dentist in private practice.

Modulation of signal transduction by vitamin E

The ability of vitamin E to modulate signal transduction and gene expression has been observed in numerous studies; however, the detailed molecular mechanisms involved are often not clear. The eight natural vitamin E analogues and synthetic derivatives affect signal transduction with different potency, possibly reflecting their different ability to interact with specific proteins. Vitamin E modulates the activity of several enzymes involved in signal transduction, such as protein kinase C, protein kinase B, protein tyrosine kinases, 5-, 12-, and 15-lipoxygenases, cyclooxygenase-2, phospholipase A2, protein phosphatase 2A, protein tyrosine phosphatase, and diacylglycerol kinase. Activation of some these enzymes after stimulation of cell surface receptors with growth factors or cytokines can be normalized by vitamin E. At the molecular level, the translocation of several of these enzymes to the plasma membrane is affected by vitamin E, suggesting that the modulation of protein-membrane interactions may be a common theme for vitamin E action. In this review the main effects of vitamin E on enzymes involved in signal transduction are summarized and the possible mechanisms leading to enzyme modulation evaluated. The elucidation of the molecular and cellular events affected by vitamin E could reveal novel strategies and molecular targets for developing similarly acting compounds.

Statistical finite element model for bone shape and biomechanical properties

We present a framework for statistical finite element analysis combining shape and material properties, and allowing performing statistical statements of biomechanical performance across a given population. In this paper, we focus on the design of orthopaedic implants that fit a maximum percentage of the target population, both in terms of geometry and biomechanical stability. CT scans of the bone under consideration are registered non-rigidly to obtain correspondences in position and intensity between them. A statistical model of shape and intensity (bone density) is computed by means of principal component analysis. Afterwards, finite element analysis (FEA) is performed to analyse the biomechanical performance of the bones. Realistic forces are applied on the bones and the resulting displacement and bone stress distribution are calculated. The mechanical behaviour of different PCA bone instances is compared.

The foundations of computer assisted surgery

Using navigation systems in general orthopaedic surgery and, in particular, knee replacement is becoming more and more accepted. This paper describes the basic technological concepts of modern computer assisted surgical systems. It explains the variation in currently available systems and outlines research activities that will potentially influence future products. In general, each navigation system is defined by three components: (1) the therapeutic object is the anatomical structure that is operated on using the navigation system, (2) the virtual object represents an image of the therapeutic object, with radiological images or computer generated models potentially being used, and (3) last but not least, the navigator acquires the spatial position and orientation of instruments and anatomy thus providing the necessary data to replay surgical action in real-time on the navigation system's screen.

Reconstruction of patient-specific 3D bone surface from 2D calibrated fluoroscopic images and point distribution model

Reconstruction of patient-specific 3D bone surface from 2D calibrated fluoroscopic images and a point distribution model is discussed. We present a 2D/3D reconstruction scheme combining statistical extrapolation and regularized shape deformation with an iterative image-to-model correspondence establishing algorithm, and show its application to reconstruct the surface of proximal femur. The image-to-model correspondence is established using a non-rigid 2D point matching process, which iteratively uses a symmetric injective nearest-neighbor mapping operator and 2D thin-plate splines based deformation to find a fraction of best matched 2D point pairs between features detected from the fluoroscopic images and those extracted from the 3D model. The obtained 2D point pairs are then used to set up a set of 3D point pairs such that we turn a 2D/3D reconstruction problem to a 3D/3D one. We designed and conducted experiments on 11 cadaveric femurs to validate the present reconstruction scheme. An average mean reconstruction error of 1.2 mm was found when two fluoroscopic images were used for each bone. It decreased to 1.0 mm when three fluoroscopic images were used.

Multimodal augmented reality system for surgical microscopy

Image-guided, computer-assisted neurosurgery has emerged to improve localization and targeting, to provide a better anatomic definition of the surgical field, and to decrease invasiveness. Usually, in image-guided surgery, a computer displays the surgical field in a CT/MR environment, using axial, coronal or sagittal views, or even a 3D representation of the patient. Such a system forces the surgeon to look away from the surgical scene to the computer screen. Moreover, this kind of information, being pre-operative imaging, can not be modified during the operation, so it remains valid for guidance in the first stage of the surgical procedure, and mainly for rigid structures like bones. In order to solve the two constraints mentioned before, we are developing an ultrasoundguided surgical microscope. Such a system takes the advantage that surgical microscopy and ultrasound systems are already used in neurosurgery, so it does not add more complexity to the surgical procedure. We have integrated an optical tracking device in the microscope and an augmented reality overlay system with which we avoid the need to look away from the scene, providing correctly aligned surgical images with sub-millimeter accuracy. In addition to the standard CT and 3D views, we are able to track an ultrasound probe, and using a previous calibration and registration of the imaging, the image obtained is correctly projected to the overlay system, so the surgeon can always localize the target and verify the effects of the intervention. Several tests of the system have been already performed to evaluate the accuracy, and clinical experiments are currently in progress in order to validate the clinical usefulness of the system.