249 research outputs found

    Identification of Mgenia fuscovaria (Stål)(Hemiptera: Cicadellidae), a vector of aster yellows disease on grapevines in South Africa, and differentiation from Mgenia angusta (Theron) by nucleotide sequences of the mitochondrial cytochrome oxidase I (cox1) gene

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    Aster yellows phytoplasma (AY), only recently reported in South Africa and still limited in its distribution in the country, causes a serious disease of grapevine. A leafhopper, Mgenia fuscovaria (Stål)(Hemiptera: Cicadellidae), was shown to transmit AY to grapevine (Vitis vinifera L.) locally. A second Mgenia species, identified as Mgenia angusta (Theron), has also been found in vineyards in South Africa but has not been shown to transmit AY. M. angusta is morphologically similar to M. fuscovaria, but does differ regarding the size of the male sex organ and in the number of teeth of the blades making up the ovipositor. In this study, we determined the nucleotide sequence of the mitochondrial cytochrome oxidase I gene (cox1),commonly used in insect bar-coding, of a number of specimens of males, females and nymphs of both M. fuscovaria and M. angusta. No differences were observed between the cox1 sequences of the male, female and nymph specimens putatively assigned to any specific species, but some nucleotide sequence differences were observed between specimens of M. fuscovaria and M. angusta. These differences, however, were insufficient to allow the development of PCR systems specific to each species

    Production and use of an antiserum to grapevine virus B capsid protein purified from SDS-polyacrylamide gels

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    Antiserum to electrophoretically-separated capsid protein of grapevine virus B (GVB) was produced. After easy and effective elimination of antibodies cross-reactive with grapevine virus A (GVA), the antiserum was successfully used in ELISA for the detection of GVB in grapevines

    Detection of two strains of grapevine leafroll-associated virus 2

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    Two strains of grapevine leafroll-associated virus 2 (GLRaV-2) were obtained by mechanical transmission from grapevines to Nicotiana benthantiana. The strains, designated 94/970 and 93/955, consistently differed with regard to the development of symptoms. The first induced chlorotic and occasional white-necrotic local lesions while the second induced chlorotic followed by metallic-opalescent, solid necrotic local lesions. The strains were indistinguishable with regard to the molecular weight of their capsid proteins or serologically. A difference in the pattern of minor dsRNA bands was consistently observed

    Determinants of communication between partners about STD symptoms: implications for partner referral in South Africa

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    BackgroundSTDs as preventable diseases are a major public health problem in South Africa, both in terms of their effect on quality of life, their economic costs and the fact that STDs as co-factors drive the HIV epidemic. Their widespread occurrence and high prevalence rates are cause for concern. It is argued that the duration of infection increases the probability of harmful sequelae and STD transmission, including HIV, to others. The promotion of seeking health care for STD symptoms at an early stage and partner referral for STD treatment are important strategies in preventing STD transmission to others and re-infection of partners. The cost implications of contact tracing by healthcare workers has resulted in patients being encouraged to refer their partners for STD treatment. This has not always been effective, despite efforts to improve partner referral rates by improved “contact cards” (i.e. a card with a code representing the STD that the patient has been treated for to be given to sexual partners as a way to speed up treatment) and more accessible healthcare services. Other studies have found that the proportion of clients who present with contact cards at STD services ranged from about 2% to 39%, while the proportion of partners who were referred for treatment range from 16% to 30%. Mathews et al. argue that returning contact cards might not be a sensitive enough proxy indicator for partner referral rates.Partner referrals have been found to be seriously compromised by patients' causal explanations for STDs, as well as by the unequal power of the genders in sexual relationships, which impacts on the patients' ability to communicate about sexual matters. Patients often lack an understanding of the importance of referring their asymptomatic partners for treatment. Women's inability to discuss sexual issues due to their unequal status in sexual relationships might impact on partner referral behaviour. Men have been found to blame the STD on the “outside women” (sexual partners outside the primary relationship) and are therefore less likely to refer these partners. The conflict that could arise from informing a partner about an STD was viewed by men as a reason not to communicate about having a STD.While the ability to communicate about STDs with sexual partners is an essential prerequisite for referring them for medical treatment, little attention has been paid to understanding this process. This study is aimed at gaining some understanding of the determinants of communication between partners about STD symptoms. In this study, “talking with a partner about STD symptoms” before seeking medical treatment was viewed as an indication of the likelihood of future partner referral behaviour.Methods A randomly selected sample of 1 477 patients with STD symptoms was interviewed using a structured questionnaire. Logistic regression analysis was used to identify the determinants of talking to a partner about the present STD.ResultsIt was found that patients who had talked with their partner about their current STD symptoms were more likely to be female, be employed, have a tertiary level of education, have had only one sexual partner in the preceding six months, have used condoms, albeit inconsistently during the last six months, and to have thought about abstaining from sex while infected. Those who talked were also more likely to have good knowledge about the effects of STDs and the transmission of STDs in the absence of symptoms, had positive attitudes towards condoms and perceived social support for partner referral.ConclusionImproved partner referral through health education interventions needs to focus specifically on a subgroup of patients, e.g. men and the unemployed, and on the improvement of knowledge regarding the consequences of STDs and asymptomatic transmission. Social and partner support for partner referral and perceived self-efficacy in this regard should be encouraged and maintained. In the absence of skills and counselling services to manage the consequences of STD partner referral, this prevention strategy will remain vulnerable.For full text, click here:SA Fam Pract 2006;48(7):17-17

    Redetermination of chlorido(2,2′:6′,2′′-terpyridine-κ3 N,N′,N′′)gold(I) dichloride trihydrate at 173 K

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    The redetermined structure of the title compound, [AuCl(C15H11N3)]Cl2·3H2O, at 173 (2) K is reported. The structure displays O—H⋯Cl and O—H⋯O hydrogen bonding. The distance of one of the chloride ions from the gold(I) atom [5.047 (1) Å] differs from that determined previously

    Highway to heaven: mammary gland development and differentiation

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    In recent years, the mammary gland epithelium has been shown to be a mixture of differentiated cell populations in a hierarchical relationship with their stem and progenitor cells. However, the mechanisms that regulate their cellular differentiation processes are still unclear. The identification of genes that govern stem and progenitor cell expansion, or that determine daughter cell fate, will be of crucial interest for understanding breast cancer diversity and, ultimately, improving treatment. Two recent analyses have identified some of the key genes that regulate these processes, lighting up the highway to normal mammary gland development

    Thyroid dysfunction and electrocardiographic changes in subjects without arrhythmias:a cross-sectional study of primary healthcare subjects from Copenhagen

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    ObjectiveThe objective of the present study was to investigate associations of both overt and subclinical thyroid dysfunction with common ECG parameters in a large primary healthcare population.DesignCross-sectional study.Setting and participantsThe study population comprised of primary healthcare patients in Copenhagen, Denmark, who had a thyroid function test and an ECG recorded within 7 days of each other between 2001 and 2011.Data sourcesThe Danish National Patient Registry was used to collect information regarding baseline characteristics and important comorbidities.Outcome measure and study groupsCommon ECG parameters were determined using Marquette 12SL software and were compared between the study groups. The study population was divided into five groups based on their thyroid status. Euthyroid subjects served as the reference group in all analyses.ResultsA total of 132 707 patients (age 52±17 years; 50% female) were included. Hyperthyroidism was significantly associated with higher heart rate and prolonged QTc interval with significant interaction with age (p<0.009) and sex (p<0.001). These associations were less pronounced for patients with higher age. Subclinical hyperthyroidism was associated with higher heart rate among females, and a similar trend was observed among males. Hypothyroidism was associated with slower heart rate and shorter QTc but only in women. Moreover, longer P-wave duration, longer PR interval and low voltage were observed in patients with both subclinical and overt hypothyroidism. However, the presence of low voltage was less pronounced with higher age (p=0.001).ConclusionBoth overt and subclinical thyroid disorders were associated with significant changes in important ECG parameters. Age and gender have significant impact on the association of thyroid dysfunction particularly on heart rate and QTc interval

    Outcomes, infectiousness, and transmission dynamics of patients with extensively drug-resistant tuberculosis and home-discharged patients with programmatically incurable tuberculosis: a prospective cohort study.

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    BACKGROUND: The emergence of programmatically incurable tuberculosis threatens to destabilise control efforts. The aim of this study was to collect prospective patient-level data to inform treatment and containment strategies. METHODS: In a prospective cohort study, 273 South African patients with extensively drug-resistant tuberculosis, or resistance beyond extensively drug-resistant tuberculosis, were followed up over a period of 6 years. Transmission dynamics, infectiousness, and drug susceptibility were analysed in a subset of patients from the Western Cape using whole-genome sequencing (WGS; n=149), a cough aerosol sampling system (CASS; n=26), and phenotypic testing for 18 drugs (n=179). FINDINGS: Between Oct 1, 2008, and Oct 31, 2012, we enrolled and followed up 273 patients for a median of 20·3 months (IQR 9·6-27·8). 203 (74%) had programmatically incurable tuberculosis and unfavourable outcomes (treatment failure, relapse, default, or death despite treatment with a regimen based on capreomycin, aminosalicylic acid, or both). 172 (63%) patients were discharged home, of whom 104 (60%) had an unfavourable outcome. 54 (31%) home-discharged patients had failed treatment, with a median time to death after discharge of 9·9 months (IQR 4·2-17·4). 35 (20%) home-discharged cases were smear-positive at discharge. Using CASS, six (23%) of 26 home-discharged cases with data available expectorated infectious culture-positive cough aerosols in the respirable range (<5 μm), and most reported inter-person contact with suboptimal protective mask usage. WGS identified 17 (19%) of the 90 patients (with available sequence data) that were discharged home before the diagnosis of 20 downstream cases of extensively drug-resistant tuberculosis with almost identical sequencing profiles suggestive of community-based transmission (five or fewer single nucleotide polymorphisms different and with identical resistance-encoding mutations for 14 drugs). 11 (55%) of these downstream cases had HIV co-infection and ten (50%) had died by the end of the study. 22 (56%) of 39 isolates in patients discharged home after treatment failure were resistant to eight or more drugs. However, five (16%) of 31 isolates were susceptible to rifabutin and more than 90% were likely to be sensitive to linezolid, bedaquiline, and delamanid. INTERPRETATION: More than half of the patients with programmatically incurable tuberculosis were discharged into the community where they remained for an average of 16 months, were at risk of expectorating infectious cough aerosols, and posed a threat of transmission of extensively drug-resistant tuberculosis. Urgent action, including appropriate containment strategies, is needed to address this situation. Access to delamanid, bedaquiline, linezolid, and rifabutin, when appropriate, must be accelerated along with comprehensive drug susceptibility testing. FUNDING: UK Medical Research Council, South African Medical Research Council, South African National Research Foundation, European & Developing Countries Clinical Trials Partnership, Oppenheimer Foundation, Newton Fund, Biotechnology and Biological Sciences Research Council, King Abdullah University of Science & Technology
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