An interesting diagnosis for a presacral mass: case report

A presacral mass can present a diagnostic dilemma for the surgical oncologist. Differential diagnoses include congenital causes such as teratoma or chordoma, neurological causes such as neurilemoma or neurofibroma or other malignancies such as lymphoma or sarcoma. Diagnosis usually requires imaging such as CT and MRI and tissue biopsy. We present an unusual cause of a presacral mass being extramedullary haematopoiesis, found incidentally in a 71 year old female. Extramedullary haematopoiesis is defined as the production of myeloid and erythroid elements outside of the bone-marrow. This diagnosis is extremely rare in the presacral area especially in a patient with no haematological abnormalities. A review of the literature is presented.     

Fracture prevention in COPD patients; a clinical 5-step approach

Although osteoporosis and its related fractures are common in patients with COPD, patients at high risk of fracture are poorly identified, and consequently, undertreated. Since there are no fracture prevention guidelines available that focus on COPD patients, we developed a clinical approach to improve the identification and treatment of COPD patients at high risk of fracture. We organised a round-table discussion with 8 clinical experts in the field of COPD and fracture prevention in the Netherlands in December 2013. The clinical experts presented a review of the literature on COPD, osteoporosis and fracture prevention. Based on the Dutch fracture prevention guideline, they developed a 5-step clinical approach for fracture prevention in COPD. Thereby, they took into account both classical risk factors for fracture (low body mass index, older age, personal and family history of fracture, immobility, smoking, alcohol intake, use of glucocorticoids and increased fall risk) and COPD-specific risk factors for fracture (severe airflow obstruction, pulmonary exacerbations and oxygen therapy). Severe COPD (defined as postbronchodilator FEV₁ < 50% predicted) was added as COPD-specific risk factor to the list of classical risk factors for fracture. The 5-step clinical approach starts with case finding using clinical risk factors, followed by risk evaluation (dual energy X-ray absorptiometry and imaging of the spine), differential diagnosis, treatment and follow-up. This systematic clinical approach, which is evidence-based and easy-to-use in daily practice by pulmonologists, should contribute to optimise fracture prevention in COPD patients at high risk of fracture.     

Phylogenetic relationships of artiodactyls and cetaceans as deduced from the comparison of cytochrome b and 12S rRNA mitochondrial sequences

A data set of complete mitochondrial cytochrome b and 12S rDNA sequences is presented here for 17 representatives of Artiodactyla and Cetacea, together with potential outgroups (two Perissodactyla, two Carnivora, two Tethytheria, four Rodentia, and two Marsupialia). We include seven sequences not previously published from Hippopotamidae (Ancodonta) and Camelidae (Tylopoda), yielding a total of nearly 2.1 kb for both genes combined. Distance and parsimony analyses of each gene indicate that 11 clades are well supported, including the artiodactyl taxa Pecora, Ruminantia (with low 12S rRNA support), Tylopoda, Suina, and Ancodonta, as well as Cetacea, Perissodactyla, Carnivora, Tethytheria, Muridae, and Caviomorpha. Neither the cytochrome b nor the 12S rDNA genes resolve the relationships between these major clades. The combined analysis of the two genes suggests a monophyletic Cetacea +Artiodactyla clade (defined as "Cetartiodactyla"), whereas Perissodactyla, Carnivora, and Tethytheria fall outside this clade. Perissodactyla could represent the sister taxon of Cetartiodactyla, as deduced from resampling studies among outgroup lineages. Cetartiodactyla includes five major lineages: Ruminantia, Tylopoda, Suina, Ancodonta, and Cetacea, among which the phylogenetic relationships are not resolved. Thus, Suiformes do not appear to be monophyletic, justifying their split into the Suina and Ancodonta infraorders. An association between Cetacea and Hippopotamidae is supported by the cytochrome b gene but not by the 12S rRNA gene. Calculation of divergence dates suggests that the Cetartiodactyla could have diverged from other Ferungulata about 60 MYA.      

Relationships between xanthoxin,phototropism, and elongation growth in the sunflower seedling Helianthus annuus L.

For phototropic curvature of a green sunflower seedling, only the hypocotyl has to be illuminated; the tip and cotyledons are not involved in stimulus perception. The etiolated seedling is phototropically insensitive, illumination of only the hypocotyl renders it sensitive. It is concluded that the photoreceptor is located within the responding organ. In curving seedlings, the endogenous indoleacetic acid (IAA) remains evenly distributed. However, the inhibitor, xanthoxin (Xa), accumulates on the illuminated side. The degree of phototropic response is generally related to the concentration of Xa. The amount of phototropic curvature is independent of the rate of elongation growth, the former can be changed without affecting the latter, and vice versa. The data conflict with the Cholodny-Went theory, whereas they support the hypothesis of Blaauw that the phototropic reaction is caused by the local accumulation of a growth-inhibiting substance on the irradiated side.Abbreviations CCC chlormequat, (2-chloroethyl)trimethylammonium chloride - GA₃ gibberellic acid - IAA indole-3-acetic acid - Xa xanthoxin     

Bleomycin resistance: a new dominant selectable marker for plant cell transformation

Summary Plant cells are sensitive to the antibiotic bleomycin, a DNA damaging glycopeptide. A bleomycin resistance determinant, located on transposon Tn5 and functional in bacteria, has been cloned in a plant expression vector and introduced into Nicotiana plumbaginifolia using Agrobacterium tumefaciens. The expression of this determinant in plant cells confers resistance to bleomycin and allows selection of transformed plant cells.     

A Role for Neuropilins in the Interaction between Schwann Cells and Meningeal Cells

In their natural habitat, the peripheral nerve, Schwann cells (SCs) form nicely aligned pathways (also known as the bands of Büngner) that guide regenerating axons to their targets. Schwann cells that are implanted in the lesioned spinal cord fail to align in pathways that could support axon growth but form cellular clusters that exhibit only limited intermingling with the astrocytes and meningeal cells (MCs) that are present in the neural scar. The formation of cell clusters can be studied in co-cultures of SCs and MCs. In these co-cultures SCs form cluster-like non-overlapping cell aggregates with well-defined boundaries. There are several indications that neuropilins (NRPs) play an important role in MC-induced SC aggregation. Both SCs and MCs express NRP1 and NRP2 and SCs express the NRP ligands Sema3B, C and E while MCs express Sema3A, C, E and F. We now demonstrate that in SC-MC co-cultures, siRNA mediated knockdown of NRP2 in SCs decreased the formation of SC clusters while these SCs maintained their capacity to align in bands of Büngner-like columnar arrays. Unexpectedly, knockdown of NRP1 expression resulted in a significant increase in SC aggregation. These results suggest that a reduction in NRP2 expression may enhance the capacity of implanted SCs to interact with MCs that invade a neural scar formed after a lesion of the spinal cord.     

豇豆花叶病毒衣壳蛋白编码区在中间组份的RNA核苷酸序列上的定位(英文)

对豇豆花叶病毒两个衣壳蛋白(VP37和VP23)的氨基端和羧基端氨基酸序列进行了分析,这些结果可以允许VP37和VP23编码区在病毒中间组份(M)RNA的核苷酸序列上进行基因定位。这两个编码区是相邻的,并表明,从M RNA的原始翻译产物中释出VP37和VP23的蛋白酶解部位,分别是谷氨酰胺-甲硫氨酸和谷氨酰胺-甘氨酸二肽序列。     

Solid-phase enzyme immunoassay of urokinase using monoclonal antibodies

Using two monoclonal antibodies directed against urokinase, we have developed a micro enzyme-linked immunosorbant assay (ELISA) to detect and measure urokinase in biological fluids. The system presents the following characteristics: simple and rapid procedure, reproducibility, sensitivity (urokinase levels down to 1 ng/ml) and evaluation of the enzyme in biological fluids such as urine, pleural effusions, and ascitic fluids without preliminary purification.     

Use of a bioelectrochemical cell for the synthesis of (bio)chemicals

A bioelectrochemical cell containing either d-glucose oxidase (β-d-glucose:oxygen 1-oxidoreductase, EC 1.1.3.4) or xanthine oxidase (xanthine:oxygen oxidoreductase, EC 1.2.3.2) plus dichlorophenol-indophenol as electron acceptor in one half-cell, and chloroperoxidase (chloride:hydrogen-peroxide oxidoreductase, EC 1.11.1.10) in the other half-cell is described. Due to a combination of chemical, biochemical and electrochemical reactions, electricity and specific (bio)chemicals can be produced in the cell simultaneously and in both compartments. Furthermore, the oxidases in a bioelectrochemical cell are not inactivated by H₂O₂ and as a result the operational lifetimes of the oxidases were increased about five-fold.     

Enzymatic bromination of barbituric acid and some of its derivatives

Barbituric acid, 1-methyl- and 1,3-dimethylbarbituric acid, some of its 5-phenyl derivatives, and 5-chlorobarbituric acid are presented as new substrates for the bromoperoxidase isolated from the brown alga Ascophyllum nodosum. This enzyme is able to convert these substrates into the corresponding 5-bromo or 5,5-dibromo derivatives in good yields. Kinetic measurements show that the structure of the examined substrates has little or no effect on the enzymatic rate of bromination. However, at low substrate concentration the reaction rate depends on both the concentration of the organic substrate and the concentration of hydrogen peroxide. A mechanism is proposed for the reactions of bromoperoxidase with its substrates. These reactions involve the formation of free hypobromous acid which can either brominate the organic halogen acceptor or produce singlet oxygen by a competing reaction with hydrogen peroxide.