Hamiltonella defensa,genome evolution of protective bacterial endosymbiont from pathogenic ancestors

Eukaryotes engage in a multitude of beneficial and deleterious interactions with bacteria. Hamiltonella defensa, an endosymbiont of aphids and other sap-feeding insects, protects its aphid host from attack by parasitoid wasps. Thus H. defensa is only conditionally beneficial to hosts, unlike ancient nutritional symbionts, such as Buchnera, that are obligate. Similar to pathogenic bacteria, H. defensa is able to invade naive hosts and circumvent host immune responses. We have sequenced the genome of H. defensa to identify possible mechanisms that underlie its persistence in healthy aphids and protection from parasitoids. The 2.1-Mb genome has undergone significant reduction in size relative to its closest free-living relatives, which include Yersinia and Serratia species (4.6–5.4 Mb). Auxotrophic for 8 of the 10 essential amino acids, H. defensa is reliant upon the essential amino acids produced by Buchnera. Despite these losses, the H. defensa genome retains more genes and pathways for a variety of cell structures and processes than do obligate symbionts, such as Buchnera. Furthermore, putative pathogenicity loci, encoding type-3 secretion systems, and toxin homologs, which are absent in obligate symbionts, are abundant in the H. defensa genome, as are regulatory genes that likely control the timing of their expression. The genome is also littered with mobile DNA, including phage-derived genes, plasmids, and insertion-sequence elements, highlighting its dynamic nature and the continued role horizontal gene transfer plays in shaping it.     

Vincristine, prednisone and L-asparaginase in the induction of remission in children with acute lymphoblastic leukemia following relapse.

Two hundred and twenty-seven children with recurrent acute lymphoblastic leukemia were treated with various combinations of vincristine, prednisone, cyclophosphamide and L-asparaginase in an approach to the induction of remission. The combination of L-asparaginase 1,000 mu/kg iv q.d. x 10, vincristine 2.0 mg/m2iv q.w. x 4 and prednisone 40 mg/m2 p.o.q.d. x 28 days was found to be highly effective. The incidence of remission was 73%. No significant improvement was achieved when cyclophosphamide was added to this regimen. Various combinations of cytosine arabinoside, cyclophosphamide, vincristine, prednisone, BCNU or CCNU failed to maintain remission duration for more than two or three months. Neither BCNU nor CCNU prevented the development of CNS leukemia.     

Ultrastructural cytochemical analysis of blastic transformation of chronic myelocytic leukemia.

Ultrastructural cytochemical changes occurring during the blast phase of chronic myelocytic leukemia (CML) are described. Normal developing promyelocytes contain myeloperoxidase (MPO) -positive rough endoplasmic reticulum, nuclear envelope, and Golgi apparatus. All secretory granules of normal promyelocytes are also MPO-positive. In this study we have found abnormal promyelocytes with MPO-positive as well as MPO-negative secretory granules in blast phase CML patients which contrast with the normal pattern of MPO distribution in most CML patients not in the blast phase or in nonleukemic controls. Alkaline phosphatase activity was found in the nuclear envelope of blasts and promyelocytes of one of the blast transformation patients who had a markedly increased leukocyte alkaline phosphatase score. The cytochemical changes in the distribution of MPO suggest that immature leukemic cells may alter their patterns of secretory granule production. Such processes may reflect the emergence of an abnormal clone of cells during the blastic transformation of CML.     

Validation of a physically based catchment model for application in post-closure radiological safety assessments of deep geological repositories for solid radioactive wastes.

The physically based river catchment modelling system SHETRAN incorporates components representing water flow, sediment transport and radionuclide transport both in solution and bound to sediments. The system has been applied to simulate hypothetical future catchments in the context of post-closure radiological safety assessments of a potential site for a deep geological disposal facility for intermediate and certain low-level radioactive wastes at Sellafield, west Cumbria. In order to have confidence in the application of SHETRAN for this purpose, various blind validation studies have been undertaken. In earlier studies, the validation was undertaken against uncertainty bounds in model output predictions set by the modelling team on the basis of how well they expected the model to perform. However, validation can also be carried out with bounds set on the basis of how well the model is required to perform in order to constitute a useful assessment tool. Herein, such an assessment-based validation exercise is reported. This exercise related to a field plot experiment conducted at Calder Hollow, west Cumbria, in which the migration of strontium and lanthanum in subsurface Quaternary deposits was studied on a length scale of a few metres. Blind predictions of tracer migration were compared with experimental results using bounds set by a small group of assessment experts independent of the modelling team. Overall, the SHETRAN system performed well, failing only two out of seven of the imposed tests. Furthermore, of the five tests that were not failed, three were positively passed even when a pessimistic view was taken as to how measurement errors should be taken into account. It is concluded that the SHETRAN system, which is still being developed further, is a powerful tool for application in post-closure radiological safety assessments.     

Anomalous ABO inheritance explained by ovum transplantation

BACKGROUND: Modern fertilization techniques can lead to unexpected ABO phenotypes in newborn infants and can raise questions as to maternity, paternity, and infant misidentification. Ovum transplantation can result in an infant with an ABO phenotype that is unexpected, given the birth mother's ABO type. STUDY DESIGN AND METHODS: A group AB, Rh- positive female infant was born to a group O, Rh-positive woman as a result of ovum transplantation. The case report is provided. RESULTS: The birth mother typed group O, Rh-positive both before and after delivery. The infant typed group AB, Rh-positive on cord blood and heelstick specimens. CONCLUSION: Ovum transplantation can result in newborns whose ABO phenotypes are unexpected, in relation to the birth mother's ABO type. To ensure patient privacy, such fertilization techniques may not be clearly documented in the delivery room chart. A complete obstetric history helps prevent repeat phlebotomies, expensive and unnecessary typing studies, and concern of the clinical staff with possible sample or infant misidentification.     

Cytokines in inflammatory malignant fibrous histiocytoma presenting with leukemoid reaction

Inflammatory malignant fibrous histiocytomas (IMFH) are rare tumors and are frequently associated with leukocytosis. In rare cases, leukemoid reactions were attributed to tumor production of unidentified hematopoietic factors. In this study, we used immunohistochemical techniques to show cytokine immunoreactivity in the malignant cells of two cases of IMFH presenting with leukemoid reactions and compared them with two malignant fibrous histocytomas, noninflammatory type. All four tumors stained positively for stem cell factor (SCF), granulocyte colony-stimulating factor (G-CSF), interleukin-2 (IL-2), IL-4, IL-5, interferon-alpha (IFN-alpha), and insulin-like growth factor-I. Other cytokines detected only in the two IMFH included IL-6, IL-7, IL-8, IFN- gamma, and keratinocyte growth factor. Granulocyte-macrophage-CSF, IL- 3, and transforming growth factor-beta staining was present in one of the two IMFH tumors and was not present in the noninflammatory tumors. The immunohistochemical staining was localized to the malignant cells, suggesting deregulated cytokine expression consistent with their monocytic/histocytic origin. Expression of certain cytokines in the IMFH may account for the local inflammatory infiltrate, tumor fibrosis, and the aggressive nature of the malignant cells. We also detected elevated serum levels of SCF, G-CSF, IL-6, and tumor necrosis factor in one or both of the IMFH patients. These latter observations may explain the bone marrow hypercellularity and other paraneoplastic symptoms, including fever, malaise, and weight loss, observed in both patients. Different cytokines present in the two IMFH tumors appear to be responsible for the eosinophilic leukemoid reaction observed in one case and for the granulocytic leukemoid reaction observed in the other patient. They may also be responsible for expansion of the tumor-cell population, fibroblast proliferation, and enhanced secretion of extracellular collagen.     

Proof-of-concept study on the suitability of 13C-urea as a marker substance for assessment of in vivo behaviour of oral colon-targeted dosage forms

Background and purpose:

¹³C-urea may be a suitable marker to assess the in vivo fate of colon-targeted dosage forms given by mouth. We postulated that release in the colon (urease-rich segment) of ¹³C-urea from colon-targeted capsules would lead to fermentation of ¹³C-urea by bacterial ureases into ¹³CO₂. Subsequent absorption into the blood and circulation would lead to detectable ¹³C (as ¹³CO₂) in breath. If, however, release of ¹³C-urea occurred in the small intestine (urease-poor segment), we expected detectable ¹³C (as ¹³C-urea) in blood but no breath ¹³C (as ¹³CO₂). The differential kinetics of ¹³C-urea could thus potentially describe both release kinetics and indicate the gastrointestinal segment of release.

Experimental approach:

The in vivo study consisted of three experiments, during which the same group of four volunteers participated.

Key results:

The kinetic model was internally valid. The appearance of ¹³C-in breath CO₂ (F_fermented) and the appearance of ¹³C in blood as ¹³C-urea (F_{not fermented}) show a high inverse correlation (Pearson''s r=−0.981, P= 0.06). The total recovery of ¹³C (F_fermented+F_{not fermented}) averaged 99%, indicating complete recovery of the administered ¹³C via breath and blood. ¹³CO₂ exhalation was observed in all subjects. This indicates that ¹³C-urea was available in urease-rich segments, such as the caecum or colon.

Conclusions and implications:

In this proof-of-concept study, ¹³C-urea was able to provide information on both the release kinetics of a colon-targeted oral dosage form and the gastrointestinal segment where it was released.     

Evaluation of Ultrasmall Superparamagnetic Iron Oxide-Enhanced MRI of Carotid Atherosclerosis to Assess Risk of Cerebrovascular and Cardiovascular Events: Follow-Up of the ATHEROMA Trial

No abstract available.     

Synergistic effects of glycoprotein 130 binding cytokines in combination with interleukin-1 on cartilage collagen breakdown

OBJECTIVE: To determine whether other glycoprotein 130 (gp130) binding cytokines can mimic the effects of oncostatin M (OSM) in acting synergistically with interleukin-1alpha (IL-1alpha) to induce cartilage collagen breakdown and collagenase expression, and to determine which receptors mediate these effects. METHODS: The release of collagen and proteoglycan was assessed in bovine and human cartilage explant cultures. Messenger RNA (mRNA) and protein production from immortalized human chondrocytes (T/C28a4) was analyzed by Northern blotting and specific enzyme-linked immunosorbent assays. Collagenase activity was measured by bioassay. Cell surface receptors were detected by flow cytometry. RESULTS: OSM in combination with IL-1alpha caused a rapid synergistic induction of matrix metalloproteinase 1 mRNA, which was sustained over a 72-hour period. Flow cytometric analyses detected both the OSM-specific receptor and the gp130 receptor at the chondrocyte cell surface, but failed to detect the leukemia inhibitory factor receptor (LIFR). Cartilage degradation assays revealed that, of the gp130 binding cytokines, only OSM and IL-6, in the presence of its soluble receptor (sIL-6R), were able to act synergistically with IL-1alpha to promote collagen release. CONCLUSION: This study demonstrates that IL-6 can mimic OSM in synergizing with IL-1alpha to induce chondrocyte-mediated cartilage collagen breakdown and collagenase production. In order to have this effect, IL-6 requires the presence of its soluble receptor. The apparent absence of LIFR explains why other gp130 binding cytokines do not act in synergy with IL-1alpha. Since OSM, IL-6, and sIL-6R levels have all been shown to be elevated in the rheumatoid joint, our findings suggest that these cytokines may be key mediators of cartilage collagen catabolism in the inflammatory arthritides.     

Local metabolism in lung airways increases the uncertainty of pyrene as a biomarker of polycyclic aromatic hydrocarbon exposure

While inhaled polycyclic aromatic hydrocarbons have long been suspected to induce lung cancer in humans, their dosimetry has not been fully elucidated. A key question is whether the critical exposure occurs during absorption in the lungs, or if toxicants in the systemic circulation contribute significantly to lung cancer risk. In particular, data are needed to determine how the physical properties of inhalants affect local dosimetry in the respiratory tract. Pyrene, a tobacco smoke component, was selected for study because it has physical properties between those of highly lipophilic benzo[a]pyrene and water- soluble nitrosamines. Aliquots of 5 ng of pyrene dissolved in a phospholipid/ saline suspension were instilled as a single-spray bolus in the posterior trachea of the dog just anterior to the carina. For 3 h after instillation, blood was repeatedly sampled from the azygous vein, which drains the mucosa around the point of instillation, and from both sides of the systemic circulation. At 3 h post-instillation, tissue samples were taken. Autoradiography was used to determine the depth distribution of pyrene in the tracheal mucosa. The concentration of pyrene-equivalent radioactivity in the azygous vein peaked 9 min after the instillation. At approximately 30 min after instillation, a rapid early clearance phase shifted into a distinctly slower second clearance phase. Rates of rapid clearance were, however, sufficiently slow to indicate diffusion-limited absorption of pyrene in the trachea. This finding was corroborated by high concentrations of pyrene in the epithelium as determined by autoradiography. High epithelial concentration of pyrene combined with a slow penetration into the circulating blood allowed substantial first-pass metabolic conversion of pyrene in the tracheal mucosa. A total of 13% of the instilled pyrene was retained in the tracheal mucosa 3.2 h after instillation; of this, 29% was parent compound, 52% was organic-extractable metabolites, 14% was water-soluble metabolites and 6% (approximately 1% of the instilled amount) was covalently bound to tracheal tissues. Results support the inference that lipophilic protoxicants, because of slow, diffusion-limited absorption, are more likely than water-soluble protoxicants to be bioactivated in the lining epithelium and, in turn, induce first-pass toxicity at the site of entry. In addition, limitations were identified in the use of systemically distributed biomarkers of PAHs, such as urinary hydroxypyrene levels, as indicators of the biologically effective dose in airway target cells.