Primary pyogenic spondylitis following kyphoplasty: a case report

<p>Abstract</p> <p>Introduction</p> <p>Only ten cases of primary pyogenic spondylitis following vertebroplasty have been reported in the literature. To the best of our knowledge, we present the first reported case of primary pyogenic spondylitis and spondylodiscitis caused by kyphoplasty.</p> <p>Case presentation</p> <p>A 72-year old Caucasian man with an osteoporotic compression fracture of the first lumbar vertebra after kyphoplasty developed sensory incomplete paraplegia below the first lumbar vertebra. This was caused by myelon compression following pyogenic spondylitis with a psoas abscess. Computed tomography guided aspiration of the abscess cavity yielded group C <it>Streptococcus</it>. The psoas abscess was percutaneously drained and laminectomy and posterior instrumentation with an internal fixator from the eleventh thoracic vertebra to the fourth lumbar vertebra was performed. In a second operation, corpectomy of the first lumbar vertebra with cement removal and fusion from the twelfth thoracic vertebra to the second lumbar vertebra with a titanium cage was performed. Six weeks postoperatively, the patient was pain free with no neurologic deficits or signs of infection.</p> <p>Conclusion</p> <p>Pyogenic spondylitis is an extremely rare complication after kyphoplasty. When these patients develop recurrent back pain postoperatively, the diagnosis of pyogenic spondylitis must be considered.</p

Star Clusters

This review concentrates almost entirely on globular star clusters. It emphasises the increasing realisation that few of the traditional problems of star cluster astronomy can be studied in isolation: the influence of the Galaxy affects dynamical evolution deep in the core, and the spectrum of stellar masses; in turn the evolution of the core determines the highest stellar densities, and the rate of encounters. In this way external tidal effects indirectly influence the formation and evolution of blue stragglers, binary pulsars, X-ray sources, etc. More controversially, the stellar density appears to influence the relative distribution of normal stars. In the opposite sense, the evolution of individual stars governs much of the early dynamics of a globular cluster, and the existence of large numbers of primordial binary stars has changed important details of our picture of the dynamical evolution. New computational tools which will become available in the next few years will help dynamical theorists to address these questions.Comment: 10 pages, 3 figures, Te

Spontaneous splenic rupture in an active duty Marine upon return from Iraq: a case report

<p>Abstract</p> <p>Introduction</p> <p>Atraumatic splenic rupture is a rare event that has been associated with several infectious disease processes. In the active duty military population, potential exposure to these pathogens is significant. Here we discuss the case of an active duty Marine with spontaneous splenic rupture upon return from a six-month deployment in Iraq.</p> <p>Case presentation</p> <p>A previously healthy 30-year-old Caucasian male active duty Marine presented with abdominal pain, fever and diarrhea after deployment to Iraq in support of Operation Iraqi Freedom. Based on clinical and radiographic evidence, a diagnosis of spontaneous splenic rupture was ultimately suspected. After exploratory laparotomy with confirmation of rupture, splenectomy was performed, and the patient made a full, uneventful recovery. Histopathologic examination revealed mild splenomegaly with a ruptured capsule of undetermined cause.</p> <p>Conclusion</p> <p>Spontaneous splenic rupture is a rare event that may lead to life-threatening hemorrhage if not diagnosed and treated quickly. Although the cause of this patient's case was unknown, atraumatic splenic rupture has been associated with a variety of infectious diseases and demonstrates some risks the active duty military population may face while on deployment. Having an awareness of these pathogens and their role in splenic rupture, clinicians caring for military personnel must be prepared to recognize and treat this potentially fatal complication.</p

Dark spinor models in gravitation and cosmology

We introduce and carefully define an entire class of field theories based on non-standard spinors. Their dominant interaction is via the gravitational field which makes them naturally dark; we refer to them as Dark Spinors. We provide a critical analysis of previous proposals for dark spinors noting that they violate Lorentz invariance. As a working assumption we restrict our analysis to non-standard spinors which preserve Lorentz invariance, whilst being non-local and explicitly construct such a theory. We construct the complete energy-momentum tensor and derive its components explicitly by assuming a specific projection operator. It is natural to next consider dark spinors in a cosmological setting. We find various interesting solutions where the spinor field leads to slow roll and fast roll de Sitter solutions. We also analyse models where the spinor is coupled conformally to gravity, and consider the perturbations and stability of the spinor.Comment: 43 pages. Several new sections and details added. JHEP in prin

p3d – Python module for structural bioinformatics

<p>Abstract</p> <p>Background</p> <p>High-throughput bioinformatic analysis tools are needed to mine the large amount of structural data via knowledge based approaches. The development of such tools requires a robust interface to access the structural data in an easy way. For this the Python scripting language is the optimal choice since its philosophy is to write an understandable source code.</p> <p>Results</p> <p>p3d is an object oriented Python module that adds a simple yet powerful interface to the Python interpreter to process and analyse three dimensional protein structure files (PDB files). p3d's strength arises from the combination of a) very fast spatial access to the structural data due to the implementation of a binary space partitioning (BSP) tree, b) set theory and c) functions that allow to combine a and b and that use human readable language in the search queries rather than complex computer language. All these factors combined facilitate the rapid development of bioinformatic tools that can perform quick and complex analyses of protein structures.</p> <p>Conclusion</p> <p>p3d is the perfect tool to quickly develop tools for structural bioinformatics using the Python scripting language.</p

Structure and mechanism of human DNA polymerase η

The variant form of the human syndrome xeroderma pigmentosum (XPV) is caused by a deficiency in DNA polymerase eta (Pol eta), a DNA polymerase that enables replication through ultraviolet-induced pyrimidine dimers. Here we report high-resolution crystal structures of human Pol eta at four consecutive steps during DNA synthesis through cis-syn cyclobutane thymine dimers. Pol eta acts like a 'molecular splint' to stabilize damaged DNA in a normal B-form conformation. An enlarged active site accommodates the thymine dimer with excellent stereochemistry for two-metal ion catalysis. Two residues conserved among Pol eta orthologues form specific hydrogen bonds with the lesion and the incoming nucleotide to assist translesion synthesis. On the basis of the structures, eight Pol eta missense mutations causing XPV can be rationalized as undermining the molecular splint or perturbing the active-site alignment. The structures also provide an insight into the role of Pol eta in replicating through D loop and DNA fragile sites

Naphthoquinones and Anthraquinones from Scent Glands of a Dyspnoid Harvestman, Paranemastoma quadripunctatum

Extracts of Paranemastoma quadripunctatum (Opiliones, Dyspnoi, Nemastomatidae) contained seven components, all of which likely originated from the secretion of well-developed prosomal scent glands. The two main components (together accounting for more than 90% of the secretion) were identified as 1,4-naphthoquinone and 6-methyl-1,4-naphthoquinone. The minor components were 1,4-naphthalenediol, two methoxy-naphthoquinones (2-methoxy-1,4-naphthoquinone, and 2-methoxy-6-methyl-1,4-naphthoquinone) and two anthraquinones (2-methyl-9,10-anthraquinone and a dimethyl-9,10-anthraquinone). While some chemical data on scent gland secretions of the other suborders of Opiliones (Cyphophthalmi, palpatorean Eupnoi, and Laniatores) already exist, this is the first report on the scent gland chemistry in the Dyspnoi. Naphthoquinones are known scent gland exudates of Cyphophthalmi and certain Eupnoi, methoxy-naphthoquinones and anthraquinones are new for opilionid scent gland secretions

Kypho-IORT - a novel approach of intraoperative radiotherapy during kyphoplasty for vertebral metastases

<p>Abstract</p> <p>Background</p> <p>Instable and painful vertebral metastases in patients with progressive visceral metastases present a common therapeutic dilemma. We developed a novel approach to deliver intraoperative radiotherapy (IORT) during kyphoplasty and report the first treated case.</p> <p>Methods/Results</p> <p>60 year old patient with metastasizing breast cancer under chemotherapy presented with a newly diagnosed painful metastasis in the 12^ththoracic vertebra. Under general anaesthesia, a bipedicular approach into the vertebra was chosen with insertion of specially designed metallic sleeves to guide the electron drift tube of the miniature X-ray generator (INTRABEAM, Carl Zeiss Surgical, Oberkochen, Germany). This was inserted with a novel sheet designed for this approach protecting the drift tube. A radiation dose of 8 Gy in 5 mm distance (50 kV X-rays) was delivered. The kyphoplasty balloons (KyphX, Kyphon Inc, Sunnyvale) were inflated after IORT and polymethylmethacrylate cement was injected. The whole procedure lasted less than 90 minutes.</p> <p>Conclusion</p> <p>In conclusion, this novel, minimally invasive procedure can be performed in standard operating rooms and may become a valuable option for patients with vertebral metastases providing immediate stability and local control. A phase I/II study is under way to establish the optimal dose prescription.</p

Metabolic Profiling of Hypoxic Cells Revealed a Catabolic Signature Required for Cell Survival

Hypoxia is one of the features of poorly vascularised areas of solid tumours but cancer cells can survive in these areas despite the low oxygen tension. The adaptation to hypoxia requires both biochemical and genetic responses that culminate in a metabolic rearrangement to counter-balance the decrease in energy supply from mitochondrial respiration. The understanding of metabolic adaptations under hypoxia could reveal novel pathways that, if targeted, would lead to specific death of hypoxic regions. In this study, we developed biochemical and metabolomic analyses to assess the effects of hypoxia on cellular metabolism of HCT116 cancer cell line. We utilized an oxygen fluorescent probe in anaerobic cuvettes to study oxygen consumption rates under hypoxic conditions without the need to re-oxygenate the cells and demonstrated that hypoxic cells can maintain active, though diminished, oxidative phosphorylation even at 1% oxygen. These results were further supported by in situ microscopy analysis of mitochondrial NADH oxidation under hypoxia. We then used metabolomic methodologies, utilizing liquid chromatography–mass spectrometry (LC-MS), to determine the metabolic profile of hypoxic cells. This approach revealed the importance of synchronized and regulated catabolism as a mechanism of adaptation to bioenergetic stress. We then confirmed the presence of autophagy under hypoxic conditions and demonstrated that the inhibition of this catabolic process dramatically reduced the ATP levels in hypoxic cells and stimulated hypoxia-induced cell death. These results suggest that under hypoxia, autophagy is required to support ATP production, in addition to glycolysis, and that the inhibition of autophagy might be used to selectively target hypoxic regions of tumours, the most notoriously resistant areas of solid tumours