n Biologiese ondersoek van Tylosema esculentum

Tylosema esculentum (Schweinf.) Schreiber belongs to the family Caesalpiniaceae in the tribe Cercideae Bronn. The species is distributed throughout Southern Africa. The combination of climate and soiltype with the occurrence of lime and dolomite seem to be determinating factors in the distribution of the species. T esculentum is a perennial geophyte with an underground tuber bearing ephemeral climbing or creeping stems. Vegetative growth and development occurs from August to May. The main stems and 1st order-lateral stems are mainly responsible for the first high intensity flowering phase during November while the 2nd order-lateral stems are responsible for the second high intensity flowering phase during January. No significant difference (p<0.05) is to be found between the development of Pin and Thrum flowering plants. T esculentum has chasmogamic, entomophylous flowers which are zygomorphic and distylous. Nectar production in the hipantium is the primary attractant of pollinators and is supplemented by two secondary attractants, viz. the bright yellow flower colour and their mild sweet aroma. The stigmas are funnel-shaped, papillate and wet. Anthesis takes 18 to 21 hours and the flowers have an average life expectancy of four days. The peak of stigma receptivity is on days two and three after anthesis. An average of 29 088 pollen grains (from only two fertile anthers) are produced per flower and a pollen viability of 25.3% for pin flowers and 21 .3% for thrum flowers was obtained using the in vitro test method. A viscous, polisaccharide and lipid-like anther-mucilage is released simultaneously with the pollen during anther dehiscence. This anther-mucilage is produced within the anther-connective tissue and is analogous, in terms of pollination ecology, to pollenkitt and viscin threads. No pre-zygotic self-incompatibility system was found. A high level of outbreeding is maintained through reciprocal herkogamy and incomplete protogyny. A contributing factor may be the availability of pollen on the first day of anthesis only, as a result of the hardening of the anther-mucilage, while the peak of stigma receptivity is on days two and three after anthesis. The possibility of the presence of a post-zygotic late-acting self-incompatibility system is, however, not completely ruled out.Dissertation (MSc)--University of Pretoria, 1990.Plant ScienceMScUnrestricte

β-D-Glucoside utilization by Mycoplasma mycoides subsp. mycoides SC: possible involvement in the control of cytotoxicity towards bovine lung cells

BACKGROUND: Contagious bovine pleuropneumonia (CBPP) caused by Mycoplasma mycoides subsp. mycoides small-colony type (SC) is among the most serious threats for livestock producers in Africa. Glycerol metabolism-associated H(2)O(2 )production seems to play a crucial role in virulence of this mycoplasma. A wide number of attenuated strains of M. mycoides subsp. mycoides SC are currently used in Africa as live vaccines. Glycerol metabolism is not affected in these vaccine strains and therefore it does not seem to be the determinant of their attenuation. A non-synonymous single nucleotide polymorphism (SNP) in the bgl gene coding for the 6-phospho-β-glucosidase (Bgl) has been described recently. The SNP differentiates virulent African strains isolated from outbreaks with severe CBPP, which express the Bgl isoform Val(204), from strains to be considered less virulent isolated from CBPP outbreaks with low mortality and vaccine strains, which express the Bgl isoform Ala(204). RESULTS: Strains of M. mycoides subsp. mycoides SC considered virulent and possessing the Bgl isoform Val(204), but not strains with the Bgl isoform Ala(204), do trigger elevated levels of damage to embryonic bovine lung (EBL) cells upon incubation with the disaccharides (i.e., β-D-glucosides) sucrose and lactose. However, strains expressing the Bgl isoform Val(204 )show a lower hydrolysing activity on the chromogenic substrate p-nitrophenyl-β-D-glucopyranoside (pNPbG) when compared to strains that possess the Bgl isoform Ala(204). Defective activity of Bgl in M. mycoides subsp. mycoides SC does not lead to H(2)O(2 )production. Rather, the viability during addition of β-D-glucosides in medium-free buffers is higher for strains harbouring the Bgl isoform Val(204 )than for those with the isoform Ala(204). CONCLUSION: Our results indicate that the studied SNP in the bgl gene is one possible cause of the difference in bacterial virulence among strains of M. mycoides subsp. mycoides SC. Bgl does not act as a direct virulence factor, but strains possessing the Bgl isoform Val(204 )with low hydrolysing activity are more prone to survive in environments that contain high levels of β-D-glucosides, thus contributing in some extent to mycoplasmaemia

Echocardiography of isolated subacute left heart tamponade in a patient with cor pulmonale and circumferential pericardial effusion

Patients with advanced idiopathic pulmonary artery hypertension have often a chronic pericardial effusion. It is the result of increased transudation and impaired re-absorption due to elevated venous pressure. These patients have pre-existent symptoms and signs of chronic right heart failure. High degree of suspicion is required to detect of development of an atypical form of tamponade with isolated compression of left heart chambers as shown in present case report. Transthoracic echocardiography provides a rapid access to the correct diagnosis, a prompt relief of symptoms following the ultrasound guided pericardiocentesis and important diagnostic tool for regular follow up of patients thereafter as shown in our case report

Lanthanopolyoxotungstates in silica nanoparticles: multi-wavelength photoluminescent core/shell materials

We thank Dr Marc Willinger and the RNME (National Electronic Microscopy Network, Portugal) for HRTEM images. Electronic supplementary information (ESI) available: FT-IR and FT-Raman spectra, additional HRTEM images and complementary photoluminescence spectra details, see DOI: 10.1039/b919691a.Photoluminescent lanthanopolyoxotungstate core/shell nanoparticles are prepared by the encapsulation of lanthanide-containing polyoxometalates (POMs) with amorphous silica shells. The preparation of morphological well-defined core/shell nanoparticles is achieved by the hydrolysis of tetraethoxysilane in the presence of POMs using a reverse microemulsion method. The POMs used are decatungstolanthanoates of [Ln(W(5)O(18))(2)](9-) type (Ln(III) = Eu, Gd and Tb). Photoluminescence studies show that there is efficient emission from the POM located inside the SiO(2) shells, through excitation paths that involve O --> Eu/Tb and O --> W ligand-to-metal charge transfer. It is also shown that the excitation of the POM containing europium(III) may be tuned towards longer wavelengths via an antenna effect, by coordination of an organic ligand such as 3-hydroxypicolinate. The POM/SiO(2) nanoparticles form stable suspensions in aqueous solution having the advantage of POM stabilization inside the core and the possibility of further surface grafting of chemical moieties via well known derivatization procedures for silica surfaces. These features together with the possibility of tuning the excitation wavelength by modifying the coordination sphere in the lanthanopolyoxometalate, make this strategy promising to develop a new class of optical bio-tags composed of silica nanobeads with multi-wavelength photoluminescent lanthanopolyoxometalate cores.FCT- POCI/QUI/58887/2004FCT- PTDC/ QUI/67712/2006FCT- SFRH/BD/30137/2006FCT- SFRH/BPD/14954/200

The PanCareSurFup consortium:research and guidelines to improve lives for survivors of childhood cancer

Background: Second malignant neoplasms and cardiotoxicity are among the most serious and frequent adverse health outcomes experienced by childhood and adolescent cancer survivors (CCSs) and contribute significantly to their increased risk of premature mortality. Owing to differences in health-care systems, language and culture across the continent, Europe has had limited success in establishing multi-country collaborations needed to assemble the numbers of survivors required to clarify the health issues arising after successful cancer treatment. PanCareSurFup (PCSF) is the first pan-European project to evaluate some of the serious long-term health risks faced by survivors. This article sets out the overall rationale, methods and preliminary results of PCSF. Methods: The PCSF consortium pooled data from 13 cancer registries and hospitals in 12 European countries to evaluate subsequent primary malignancies, cardiac disease and late mortality in survivors diagnosed between ages 0 and 20 years. In addition, PCSF integrated radiation dosimetry to sites of second malignancies and to the heart, developed evidence-based guidelines for long-term care and for transition services, and disseminated results to survivors and the public. Results: We identified 115,596 individuals diagnosed with cancer, of whom 83,333 were 5-year survivors and diagnosed from 1940 to 2011. This single data set forms the basis for cohort analyses of subsequent malignancies, cardiac disease and late mortality and case–control studies of subsequent malignancies and cardiac disease in 5-year survivors. Conclusions: PCSF delivered specific estimates of risk and comprehensive guidelines to help survivors and care-givers. The expected benefit is to provide every European CCS with improved access to care and better long-term health

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

Lanthanide compounds containing a benzo-15-crown-5 derivatised [60]fullerene and the related [Tb(H2O)(3)(NO3)(2)(acac)]. C14H20O5 supramolecular adduct

Novel lanthanum(III), europium(III) and terbium(III) compounds of a benzo-15-crown-5 [60]fulleropyrrolidine were isolated in the solid state and characterised using vibrational (infrared and Raman) spectroscopy and by 13C CP MAS NMR for the lanthanum(III) compound. The photoluminescence properties were investigated for the europium(III) and terbium(III) compounds. The related [Tb(H2O)3(NO3)2(acac)] C14H20O5 [where acac ¼ acetylacetonate and C14H20O5 ¼ benzo-15-crown-5] supramolecular adduct was isolated using similar synthetic conditions, in the absence of [60]fullerene, and its crystal structure used as a model for the coordination sphere of the lanthanide [60]fullerene derivatives, with further supporting evidence given by photoluminescence measurements

Accumulation of CCR4+ CTLA-4hi FOXP3+CD25hi Regulatory T Cells in Colon Adenocarcinomas Correlate to Reduced Activation of Conventional T Cells

BACKGROUND: Colorectal cancer usually gives rise to a specific anti-tumor immune response, but for unknown reasons the resulting immunity is not able to clear the tumor. Recruitment of activated effector lymphocytes to the tumor is important for efficient anti-tumor responses, while the presence of regulatory T cells (Treg) down-modulate tumor-specific immunity. We therefore aimed to determine homing mechanisms and activation stage of Treg and effector T cell infiltrating colon tumors compared to cells from the unaffected mucosa in patients suffering from colon adenocarcinoma. METHODOLOGY/PRINCIPAL FINDINGS: Lymphocytes were isolated from unaffected and tumor mucosa from patients with colon adenocarcinoma, and flow cytometry, immunohistochemistry, and quantitative PCR was used to investigate the homing mechanisms and activation stage of infiltrating Treg and conventional lymphocytes. We detected significantly higher frequencies of CD25(high)FOXP3⁺CD127(low) putative Treg in tumors than unaffected mucosa, which had a complete demethylation in the FOXP3 promotor. Tumor-associated Treg had a high expression of CTLA-4, and some appeared to be antigen experienced effector/memory cells based on their expression of αEβ7 (CD103). There were also significantly fewer activated T cells and more CTLA-4⁺ conventional T cells susceptible to immune regulation in the tumor-associated mucosa. In contrast, CD8⁺granzyme B⁺ putative cytotoxic cells were efficiently recruited to the tumors. The frequencies of cells expressing α4β7 and the Th1 associated chemokine receptor CXCR3 were significantly decreased among CD4⁺ T cells in the tumor, while frequencies of CD4⁺CCR4⁺ lymphocytes were significantly increased. CONCLUSIONS/SIGNIFICANCE: This study shows that CCR4⁺CTLA4(hi) Treg accumulate in colon tumors, while the frequencies of activated conventional Th1 type T cells are decreased. The altered lymphocyte composition in colon tumors will probably diminish the ability of the immune system to effectively attack tumor cells, and reducing the Treg activity is an important challenge for future immunotherapy protocols

Community Violence Exposure and Conduct Problems in Children and Adolescents with Conduct Disorder and Healthy Controls

Exposure to community violence through witnessing or being directly victimized has been associated with conduct problems in a range of studies. However, the relationship between community violence exposure (CVE) and conduct problems has never been studied separately in healthy individuals and individuals with conduct disorder (CD). Therefore, it is not clear whether the association between CVE and conduct problems is due to confounding factors, because those with high conduct problems also tend to live in more violent neighborhoods, i.e., an ecological fallacy. Hence, the aim of the present study was: (1) to investigate whether the association between recent CVE and current conduct problems holds true for healthy controls as well as adolescents with a diagnosis of CD; (2) to examine whether the association is stable in both groups when including effects of aggression subtypes (proactive/reactive aggression), age, gender, site and socioeconomic status (SES); and (3) to test whether proactive or reactive aggression mediate the link between CVE and conduct problems. Data from 1178 children and adolescents (62% female; 44% CD) aged between 9 years and 18 years from seven European countries were analyzed. Conduct problems were assessed using the Kiddie-Schedule of Affective Disorders and Schizophrenia diagnostic interview. Information about CVE and aggression subtypes was obtained using self-report questionnaires (Social and Health Assessment and Reactive-Proactive aggression Questionnaire (RPQ), respectively). The association between witnessing community violence and conduct problems was significant in both groups (adolescents with CD and healthy controls). The association was also stable after examining the mediating effects of aggression subtypes while including moderating effects of age, gender and SES and controlling for effects of site in both groups. There were no clear differences between the groups in the strength of the association between witnessing violence and conduct problems. However, we found evidence for a ceiling effect, i.e., individuals with very high levels of conduct problems could not show a further increase if exposed to CVE and vice versa. Results indicate that there was no evidence for an ecological fallacy being the primary cause of the association, i.e., CVE must be considered a valid risk factor in the etiology of CD