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Meier R, Gross N. Chemokines in neuroectodermal tumors: and now for something completely different. Semin Cancer Biol 2008; 19:67. [PMID: 19013528 DOI: 10.1016/j.semcancer.2008.10.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2008] [Accepted: 10/20/2008] [Indexed: 11/25/2022]
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Gross N, Meier R. Chemokines in neuroectodermal cancers: the crucial growth signal from the soil. Semin Cancer Biol 2008; 19:103-10. [PMID: 19015030 DOI: 10.1016/j.semcancer.2008.10.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2008] [Revised: 10/23/2008] [Accepted: 10/23/2008] [Indexed: 12/30/2022]
Abstract
Although chemokines and their receptors were initially identified as regulators of cell trafficking during inflammation and immune response, they have emerged as crucial players in all stages of tumor development, primary growth, migration, angiogenesis, and establishment as metastases in distant target organs. Neuroectodermal tumors regroup neoplasms originating from the embryonic neural crest cells, which display clinical and biological similarities. These tumors are highly malignant and rapidly progressing diseases that disseminate to similar target organs such as bone marrow, bone, liver and lungs. There is increasing evidence that interaction of several chemokine receptors with corresponding chemokine ligands are implicated in the growth and invasive characteristics of these tumors. In this review we summarize the current knowledge on the role of CXCL12 chemokine and its CXCR4 and CXCR7 receptors in the progression and survival of neuroectodermal tumors, with particular emphasis on neuroblastoma, the most typical and enigmatic neuroectodermal childhood tumor.
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Maigut J, Meier R, Zahl A, Eldik RV. Triggering Water Exchange Mechanisms via Chelate Architecture. Shielding of Transition Metal Centers by Aminopolycarboxylate Spectator Ligands. J Am Chem Soc 2008; 130:14556-69. [DOI: 10.1021/ja802842q] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Meier R, Hauser-Gerspach I, Lüthy H, Meyer J. Adhesion of oral streptococci to all-ceramics dental restorative materials in vitro. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2008; 19:3249-3253. [PMID: 18470704 DOI: 10.1007/s10856-008-3457-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2007] [Accepted: 04/16/2008] [Indexed: 05/26/2023]
Abstract
In recent years, patients have benefited from the development of better and more esthetic materials, including all-ceramics dental restorative materials. Dental plaque formation on teeth and restorative materials plays an important role in the pathogenesis of oral diseases. This study investigates initial adhesion of stationary phase streptococcal species to different all-ceramics dental restorative materials. The saliva-coated materials were incubated with the bacteria for 1 h in an in vitro flow chamber which mimics environmental conditions in the oral cavity. Number and vitality of adhering bacteria were determined microscopically after staining. Surface roughness and the composition of the materials had no distinctive influence on bacterial adhesion. However, S. mutans and S. sobrinus adhered about tenfold less numerous to all materials than the other streptococcal species. Further, there was a correlation between bacterial vitality and materials' glass content. The results showed that early plaque formation was influenced predominantly by the presence of the salivary pellicle rather than by material dependent parameters whereas the composition of the all-ceramics appeared to have influenced the percentage of viable cells during the adhesion process. This presented in vitro technique may provide a useful model to study the influence of different parameters on adherence of oral streptococcal species.
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Meier R, Schär B. Wirkung von Infektabwehr verstärkenden Pharmaka auf die Leukocytenemigration in vitro. Pathobiology 2008. [DOI: 10.1159/000160987] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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131
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Maigut J, Meier R, Eldik RV. Influence of Fluoride on the Reversible Binding of NO by [FeII(EDTA)(H2O)]2−. Inhibition of Autoxidation of [FeII(EDTA)(H2O)]2−. Inorg Chem 2008; 47:6314-21. [PMID: 18563876 DOI: 10.1021/ic800378c] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Mühlethaler-Mottet A, Meier R, Flahaut M, Bourloud KB, Nardou K, Joseph JM, Gross N. Complex molecular mechanisms cooperate to mediate histone deacetylase inhibitors anti-tumour activity in neuroblastoma cells. Mol Cancer 2008; 7:55. [PMID: 18549473 PMCID: PMC2442609 DOI: 10.1186/1476-4598-7-55] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2007] [Accepted: 06/12/2008] [Indexed: 01/01/2023] Open
Abstract
Background Histone deacetylase inhibitors (HDACi) are a new class of promising anti-tumour agent inhibiting cell proliferation and survival in tumour cells with very low toxicity toward normal cells. Neuroblastoma (NB) is the second most common solid tumour in children still associated with poor outcome in higher stages and, thus NB strongly requires novel treatment modalities. Results We show here that the HDACi Sodium Butyrate (NaB), suberoylanilide hydroxamic acid (SAHA) and Trichostatin A (TSA) strongly reduce NB cells viability. The anti-tumour activity of these HDACi involved the induction of cell cycle arrest in the G2/M phase, followed by the activation of the intrinsic apoptotic pathway, via the activation of the caspases cascade. Moreover, HDACi mediated the activation of the pro-apoptotic proteins Bid and BimEL and the inactivation of the anti-apoptotic proteins XIAP, Bcl-xL, RIP and survivin, that further enhanced the apoptotic signal. Interestingly, the activity of these apoptosis regulators was modulated by several different mechanisms, either by caspases dependent proteolytic cleavage or by degradation via the proteasome pathway. In addition, HDACi strongly impaired the hypoxia-induced secretion of VEGF by NB cells. Conclusion HDACi are therefore interesting new anti-tumour agents for targeting highly malignant tumours such as NB, as these agents display a strong toxicity toward aggressive NB cells and they may possibly reduce angiogenesis by decreasing VEGF production by NB cells.
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Burri E, Meier R. [Malnutrition in hospitals--a pilot study]. PRAXIS 2008; 97:657-663. [PMID: 18661887 DOI: 10.1024/1661-8157.97.12.657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
RATIONALE Malnutrition in hospitals is often not assessed and malnourished patients rarely receive specific nutritional therapy. METHODS 50 consecutive patients were assessed using the Nutritional Risk Score (NRS). 22 patients (intervention group, IG) with > or = 3 points were treated with 3 daily servings of a high-protein, high-caloric supplement. 28 patients (non-intervention-group, NIG) with < 3 points received standard hospital food. Body weight, body-mass-index (BMI) and laboratory values were obtained at admission and discharge. The amount of calorie and protein intake was compared to daily requirements. RESULTS Median duration of hospital stay was longer in the IG (24 d vs. 13 d, p < 0.01) and duration raised with the number of points in the NRS. Patients in the IG only had decreased albumin values (-2.9 g/l, p < 0.01), whereas patients in the NIG showed loss of body weight (-1.3 kg, p < 0.01), BMI (-0.45 kg/m2, p < 0.01) and albumin values (-2.4 g/l, p <0.01) during their stay. Transferrin levels remained unchanged. Median daily intake of calories and proteins was similar in both groups. In the IG, the percentage of required calorie (94% vs. 79%, p < 0.01) and protein (80% vs. 68%, p < 0.01) intake was higher and the number of patients with intake of < 75% of estimated calorie (7 (32%) vs. 11 (39%), p = 0.01) and protein (13 (59%) vs. 22 (79%), p = 0.04) requirements was lower. CONCLUSIONS Patients in the IG were more likely to maintain their nutritional status although their hospital stay was significantly longer.
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Maigut J, Meier R, Zahl A, van Eldik R. Effect of Chelate Dynamics on Water Exchange Reactions of Paramagnetic Aminopolycarboxylate Complexes. Inorg Chem 2008; 47:5702-19. [DOI: 10.1021/ic702421z] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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135
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Meier R, Vögtlin J, Gyr K. Therapie des pyogenen Leberabszesses. Dtsch Med Wochenschr 2008. [DOI: 10.1055/s-2008-1067595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Meier R, Vögtlin J, Gyr K. Diagnostik des pyogenen Leberabszesses. Dtsch Med Wochenschr 2008. [DOI: 10.1055/s-2008-1067594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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137
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Meier R, Rix A, Demicoli D. „Der Kolonnenflüsterer”: Wesentliche Aspekte für ein erfolgreiches Troubleshooting. CHEM-ING-TECH 2008. [DOI: 10.1002/cite.200700120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Maigut J, Meier R, Zahl A, van Eldik R. The impact of tripodal chelates on water exchange kinetics and mechanisms: a variable temperature and pressure 17O NMR study to clarify the structure-reactivity relationship in [Fe(II)(L)(H2O2](-) complexes. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2008; 46 Suppl 1:S94-S99. [PMID: 18855345 DOI: 10.1002/mrc.2322] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The effect of temperature and pressure on the water exchange reaction of [Fe(II)(NTA)(H2O)2](-) and [Fe(II)(BADA)(H2O)2](-) (NTA = nitrilotriacetate; BADA = beta-alanindiacetate) was studied by 17O NMR spectroscopy. The [Fe(II)(NTA)(H2O)2](-) complex showed a water exchange rate constant, k(ex), of (3.1 +/- 0.4) x 10(6) s(-1) at 298.2 K and ambient pressure. The activation parameters DeltaH( not equal), DeltaS( not equal) and DeltaV( not equal) for the observed reaction are 43.4 +/- 2.6 kJ mol(-1), + 25 +/- 9 J K(-1) mol(-1) and + 13.2 +/- 0.6 cm(3) mol(-1), respectively. For [Fe(II)(BADA)(H2O)2](-), the water exchange reaction is faster than for the [Fe(II)(NTA)(H2O)2](-) complex with k(ex) = (7.4 +/- 0.4) x 10(6) s(-1) at 298.2 K and ambient pressure. The activation parameters DeltaH( not equal), DeltaS( not equal) and DeltaV( not equal) for the water exchange reaction are 40.3 +/- 2.5 kJ mol(-1), + 22 +/- 9 J K(-1) mol(-1) and + 13.3 +/- 0.8 cm(3) mol(-1), respectively. The effect of pressure on the exchange rate constant is large and very similar for both systems, and the numerical values for DeltaV( not equal) suggest in both cases a limiting dissociative (D) mechanism for the water exchange process.
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Meier R, Tavri S, Henning TD, Piontek G, Wels WS, Rummeny EJ, Daldrup-Link HE. Monitoring neuer Immuntherapien für Prostatakarzinome mittels Magnetresonanztomographie. ROFO-FORTSCHR RONTG 2008. [DOI: 10.1055/s-2008-1073640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Shiu A, Wang C, Ye J, Cotrutz C, Meier R, Mehta V, Vermeulen S, Chang E. Dose Distribution Comparison for the IGRT Treatment Using CyberKnife Versus LINAC IMRT Stereotactic Body Radiotherapy. Int J Radiat Oncol Biol Phys 2007. [DOI: 10.1016/j.ijrobp.2007.07.2056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Sulz MC, Manz M, Grob P, Meier R, Drewe J, Beglinger C. Comparison of two antacid preparations on intragastric acidity--a two-centre open randomised cross-over placebo-controlled trial. Digestion 2007; 75:69-73. [PMID: 17496418 DOI: 10.1159/000102627] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2007] [Accepted: 03/27/2007] [Indexed: 02/04/2023]
Abstract
BACKGROUND Rennie and Riopan Gel are 2 of the most well-known and popular over-the-counter antacids; for heartburn symptoms, pain relief is fast with both preparations. A direct comparison with respect to intragastric acidity has not been done yet. The aim of our study was therefore to compare the effects of both preparations on intragastric acidity of fasting volunteers. METHODS The study was conducted as an open, randomised, placebo-controlled, 2-centre cross-over study. On different days, 24 healthy adult volunteers (11 males and 13 females) received equimolar acid-neutralising amounts of either Riopan Gel (800 mg magaldrate) or 2 tablets of Rennie (680 mg calcium carbonate and 80 mg magnesium carbonate) or no drug (control) with a wash-out period of at least 4 days between applications. The intragastric pH was measured for 3 h by intragastric pH-metry. The primary endpoint was the median time lag before intragastric pH >3.0 was reached for 10 consecutive min after drug administration. RESULTS For both antacids, the median pH during the first 30 min after drug administration was statistically significantly different from placebo (p < 0.05), but there was a statistically significant increase in pH during the first 5 min for Riopan Gel only. CONCLUSION Compared to placebo, both antacids (Rennie and Riopan Gel) have short-lasting effects on intragastric acidity. There is no statistically significant difference between the 2 preparations, except in the first 5 min, indicating a faster onset of action for Riopan Gel. We conclude that the antacid formulation (tablet or liquid) has little influence on intragastric acidity.
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Meier R, Mühlethaler-Mottet A, Flahaut M, Coulon A, Fusco C, Louache F, Auderset K, Bourloud KB, Daudigeos E, Ruegg C, Vassal G, Gross N, Joseph JM. The chemokine receptor CXCR4 strongly promotes neuroblastoma primary tumour and metastatic growth, but not invasion. PLoS One 2007; 2:e1016. [PMID: 17925864 PMCID: PMC1995764 DOI: 10.1371/journal.pone.0001016] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2007] [Accepted: 09/19/2007] [Indexed: 11/19/2022] Open
Abstract
Neuroblastoma (NB) is a heterogeneous, and particularly malignant childhood neoplasm in its higher stages, with a propensity to form metastasis in selected organs, in particular liver and bone marrow, and for which there is still no efficient treatment available beyond surgery. Recent evidence indicates that the CXCR4/CXCL12 chemokine/receptor axis may be involved in promoting NB invasion and metastasis. In this study, we explored the potential role of CXCR4 in the malignant behaviour of NB, using a combination of in vitro functional analyses and in vivo growth and metastasis assessment in an orthotopic NB mouse model. We show here that CXCR4 overexpression in non-metastatic CXCR4-negative NB cells IGR-NB8 and in moderately metastatic, CXCR4 expressing NB cells IGR-N91, strongly increased tumour growth of primary tumours and liver metastases, without altering the frequency or the pattern of metastasis. Moreover shRNA-mediated knock-down experiments confirmed our observations by showing that silencing CXCR4 in NB cells impairs in vitro and almost abrogates in vivo growth. High levels of CXCL12 were detected in the mouse adrenal gland (the primary tumour site), and in the liver suggesting a paracrine effect of host-derived CXCL12 on NB growth. In conclusion, this study reveals a yet unreported NB-specific predominant growth and survival-promoting role of CXCR4, which warrants a critical reconsideration of the role of CXCR4 in the malignant behaviour of NB and other cancers.
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Manz M, Meier R, Schaub N, Toia D, Steuerwald M. [Esophageal intramural pseudodiverticulosis]. PRAXIS 2007; 96:1385-9. [PMID: 17907671 DOI: 10.1024/1661-8157.96.37.1385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
We report two cases of esophageal intramural pseudodiverticulosis (EIPD). EIPD is a rare condition characterized by multiple flask-shaped outpouchings in the esophageal wall representing dilated excretory ducts of submucosal glands. Dysphagia is the leading symptom. On endoscopy, minute openings in the esophageal wall, and sometimes a segmental candida esophagitis or a benign stenosis not originating from an erosive reflux esophagitis are found.
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Meier R, Rix A, Demicoli D. „Der Kolonnenflüsterer”: Wesentliche Aspekte für ein erfolgreiches Troubleshooting. CHEM-ING-TECH 2007. [DOI: 10.1002/cite.200750365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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145
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Tritschler S, Tauber S, Meier R, Stepp H, Karl A, Zaak D, Stief CG. [Fluorescence cytology. Improvement of urinary cytology]. Urologe A 2007; 46:1121-3. [PMID: 17634912 DOI: 10.1007/s00120-007-1449-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Urothelial cancer of the bladder is a frequent disease, and urinary cytology often is used as a routine diagnostic tool. But this technique has an impaired sensitivity in low-grade tumours, and as a subjective method it is highly dependent on the experience of the cytologist. Here we present the technique of fluorescence cytology as an improvement of conventional cytology. This method is potentially able to compensate for the disadvantages of urinary cytology as it is an automated process that uses the principles of 5-Ala-induced photodynamic diagnosis (PDD).
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Abstract
BACKGROUND Septic arthritis of the wrist is correlated with a high morbidity. To show diagnostic and therapeutic options we reviewed the patients treated with wrist infections at our institution for one year. METHODS The data of ten patients who were treated for septic arthritis of the wrist in 2003 and 2004 were collected in a retrospective survey. Etiology, risk factors, microorganism and resistance data were recorded. RESULTS Six infections were of an iatrogenic nature (four following surgery, one joint puncture and one joint injection). In nine cases there was a single arthritis of the wrist. One patient had oligoarthritis. In four cases Staphylococcus aureus, in one Proteus mirabilis and in one Pseudomonas aeroginosa were identified. In four cases, no microorganism could be identified. Two of the patients suffered from diabetes mellitus, one had rheumatoid arthritis. There was no significant elevation in the white blood cell count with 9.2 (4.5 - 12.5) x 10 (9)/L. Arthroscopic debridement and synovialectomy could be performed in one case. In the other cases open surgery was necessary. In four cases partial bone resection was required. Local antibiotics were installed in eight cases. All infections healed. In nine patients the joint was immobilized with an external fixation device. All patients received systemic antibiotics. Four wrists ended in an arthrodesis, one in a four-corner fusion. On average, two (1 - 6) surgical interventions were necessary per patient. The six patients without an arthrodesis had a range of motion in extension/flexion of 30-0-24 degrees. CONCLUSION Surgical treatment is sufficient in septic arthritis of the wrist. However, an early diagnosis and therapeutic intervention are essential to avoid a permanent disability.
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Su KF, Meier R, Jackson RR, Harland DP, Li D. Convergent evolution of eye ultrastructure and divergent evolution of vision-mediated predatory behaviour in jumping spiders. J Evol Biol 2007; 20:1478-89. [PMID: 17584241 DOI: 10.1111/j.1420-9101.2007.01335.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
All jumping spiders have unique, complex eyes with exceptional spatial acuity and some of the most elaborate vision-guided predatory strategies ever documented for any animal of their size. However, it is only recently that phylogenetic techniques have been used to reconstruct the relationships and key evolutionary events within the Salticidae. Here, we used data for 35 species and six genes (4.8 kb) for reconstructing the phylogenetic relationships between Spartaeinae, Lyssomaninae and Salticoida. We document a remarkable case of morphological convergence of eye ultrastructure in two clades with divergent predatory behaviour. We, furthermore, find evidence for a stepwise, gradual evolution of a complex predatory strategy. Divergent predatory behaviour ranges from cursorial hunting to building prey-catching webs and araneophagy with web invasion and aggressive mimicry. Web invasion and aggressive mimicry evolved once from an ancestral spartaeine that was already araneophagic and had no difficulty entering webs due to glue immunity. Web invasion and aggressive mimicry was lost once, in Paracyrba, which has replaced one highly specialized predation strategy with another (hunting mosquitoes). In contrast to the evolution of divergent behaviour, eyes with similarly high spatial acuity and ultrastructural design evolved convergently in the Salticoida and in Portia.
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Shiu A, Wang H, Ye J, Cotrutz C, Meier R, Mehta V, Vermeulen S, Chang E. SU-FF-T-164: Dose Distribution Comparison for the Treatment of Lung and Spinal Metastases Using CyberKnife Versus IMRT Stereotactic Body Radiotherapy. Med Phys 2007. [DOI: 10.1118/1.2760823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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149
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Maigut J, Meier R, Zahl A, van Eldik R. Elucidation of the Solution Structure and Water-Exchange Mechanism of Paramagnetic [FeII(edta)(H2O)]2-. Inorg Chem 2007; 46:5361-71. [PMID: 17530844 DOI: 10.1021/ic700472q] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The lability and structural dynamics of [Fe(II)(edta)(H(2)O)](2-) (edta = ethylenediaminetetraacetate) in aqueous solution strongly depend on solvent interactions. To study the solution structure and water-exchange mechanism, (1)H, (13)C, and (17)O NMR techniques were applied. The water-exchange reaction was studied through the paramagnetic effect of the complex on the relaxation rate of the (17)O nucleus of the bulk water. In addition to variable-temperature experiments, high-pressure NMR techniques were applied to elucidate the intimate nature of the water-exchange mechanism. The water molecule in the seventh coordination site of the edta complex is strongly labilized, as shown by the water-exchange rate constant of (2.7 +/- 0.1) x 106 s(-1) at 298.2 K and ambient pressure. The activation parameters DeltaH(not equal), DeltaS(not equal), and DeltaV(not equal) were found to be 43.2 +/- 0.5 kJ mol(-1), +23 +/- 2 J K(-1) mol(-1), and +8.6 +/- 0.4 cm(3) mol(-1), respectively, in line with a dissociatively activated interchange (Id) mechanism. The scalar coupling constant (A/h) for the Fe(II)-O interaction was found to be 10.4 MHz, slightly larger than the value A/h = 9.4 MHz for this interaction in the hexa-aqua Fe(II) complex. The solution structure and dynamics of [Fe(II)(edta)(H(2)O)](2-) were clarified by (1)H and (13)C NMR experiments. The complex undergoes a Delta,Lambda-isomerization process with interconversion of in-plane (IP) and out-of-plane (OP) positions. Acetate scrambling was also found in an NMR study of the corresponding NO complex, [Fe(III)(edta)(NO(-))](2-).
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Bischoff S, Kester L, Meier R, Radziwill R, Schwab B, Thul P. 8 Organisation, Verordnung, Zubereitung und Logistik der parenteralen Ernährung im Krankenhaus und zu Hause; die Rolle von Ernährungsteams. AKTUELLE ERNAHRUNGSMEDIZIN 2007. [DOI: 10.1055/s-2006-951868] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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