Identification of a TPX2-Like Microtubule-Associated Protein in Drosophila

Chromosome segregation during mitosis and meiosis relies on the spindle and the functions of numerous microtubule-associated proteins (MAPs). One of the best-studied spindle MAPs is the highly conserved TPX2, which has been reported to have characteristic intracellular dynamics and molecular activities, such as nuclear localisation in interphase, poleward movement in the metaphase spindle, microtubule nucleation, microtubule stabilisation, microtubule bundling, Aurora A kinase activation, kinesin-5 binding, and kinesin-12 recruitment. This protein has been shown to be essential for spindle formation in every cell type analysed so far. However, as yet, TPX2 homologues have not been found in the Drosophila genome. In this study, I found that the Drosophila protein Ssp1/Mei-38 has significant homology to TPX2. Sequence conservation was limited to the putative spindle microtubule-associated region of TPX2, and intriguingly, D-TPX2 (Ssp1/Mei-38) lacks Aurora A- and kinesin-5-binding domains, which are highly conserved in other animal and plant species, including many insects such as ants and bees. D-TPX2 uniformly localised to kinetochore microtubule-enriched regions of the metaphase spindle in the S2 cell line, and it had microtubule binding and bundling activities in vitro. In comparison with other systems, the contribution of D-TPX2 to cell division seems to be minor; live cell imaging of microtubules and chromosomes after RNAi knockdown identified significant delay in chromosome congression in only 18% of the cells. Thus, while this conserved spindle protein is present in Drosophila, other mechanisms may largely compensate for its spindle assembly and chromosome segregation functions

Optimal Timing of External Ventricular Drainage after Severe Traumatic Brain Injury: A Systematic Review

External ventricular drainage (EVD) may be used for therapeutic cerebrospinal fluid (CSF) drainage to control intracranial pressure (ICP) after traumatic brain injury (TBI). However, there is currently uncertainty regarding the optimal timing for EVD insertion. This study aims to compare patient outcomes for patients with early and late EVD insertion. Following the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines, MEDLINE/EMBASE/Scopus/Web of Science/Cochrane Central Register of Controlled Trials were searched for published literature involving at least 10 severe TBI (sTBI) patients from their inception date to December 2019. Outcomes assessed were mortality, functional outcome, ICP control, length of stay, therapy intensity level, and complications. Twenty-one studies comprising 4542 sTBI patients with an EVD were included; 19 of the studies included patients with an early EVD, and two studies had late EVD placements. The limited number of studies, small sample sizes, imbalance in baseline characteristics between the groups and poor methodological quality have limited the scope of our analysis. We present the descriptive statistics highlighting the current conflicting data and the overall lack of reliable research into the optimal timing of EVD. There is a clear need for high quality comparisons of early vs. late EVD insertion on patient outcomes in sTBI

Detection of high levels of mutations involved in anti-malarial drug resistance in Plasmodium falciparum and Plasmodium vivax at a rural hospital in southern Ethiopia

<p>Abstract</p> <p>Background</p> <p>In Ethiopia, malaria is caused by <it>Plasmodium falciparum </it>and <it>Plasmodium vivax</it>, and anti-malarial drug resistance is the most pressing problem confronting control of the disease. Since co-infection by both species of parasite is common and sulphadoxine-pyrimethamine (SP) has been intensively used, resistance to these drugs has appeared in both <it>P. falciparum </it>and <it>P. vivax </it>populations. This study was conducted to assess the prevalence of anti-malarial drug resistance in <it>P. falciparum </it>and <it>P. vivax </it>isolates collected at a rural hospital in southern Ethiopia.</p> <p>Methods</p> <p>A total of 1,147 patients with suspected malaria were studied in different months across the period 2007-2009. <it>Plasmodium falciparum dhfr </it>and <it>dhps </it>mutations and <it>P. vivax dhfr </it>polymorphisms associated with resistance to SP, as well as <it>P. falciparum pfcrt </it>and <it>pfmdr1 </it>mutations conferring chloroquine resistance, were assessed.</p> <p>Results</p> <p>PCR-based diagnosis showed that 125 of the 1147 patients had malaria. Of these, 52.8% and 37.6% of cases were due to <it>P. falciparum </it>and <it>P. vivax </it>respectively. A total of 10 cases (8%) showed co-infection by both species and two cases (1.6%) were infected by <it>Plasmodium ovale</it>. <it>Pfdhfr </it>triple mutation and <it>pfdhfr/pfdhps </it>quintuple mutation occurred in 90.8% (95% confidence interval [CI]: 82.2%-95.5%) and 82.9% (95% CI: 72.9%-89.7%) of <it>P. falciparum </it>isolates, respectively. <it>Pfcrt </it>T76 was observed in all cases and <it>pfmdr1 </it>Y86 and <it>pfmdr1 </it>Y1246 in 32.9% (95% CI: 23.4%-44.15%) and 17.1% (95% CI: 10.3-27.1%), respectively. The <it>P. vivax dhfr </it>core mutations, N117 and R58, were present in 98.2% (95% CI: 89.4-99.9%) and 91.2% (95% CI: 80.0-96.7%), respectively.</p> <p>Conclusion</p> <p>Current molecular data show an extraordinarily high frequency of drug-resistance mutations in both <it>P. falciparum </it>and <it>P. vivax </it>in southern Ethiopia. Urgent surveillance of the emergence and spread of resistance is thus called for. The level of resistance indicates the need for implementation of entire population access to the new first-line treatment with artemether-lumefantrine, accompanied by government monitoring to prevent the emergence of resistance to this treatment.</p

In vivo efficacy of artemether-lumefantrine against uncomplicated Plasmodium falciparum malaria in Central Ethiopia

<p>Abstract</p> <p>Background</p> <p><it>In vivo </it>efficacy assessments of the first-line treatments for <it>Plasmodium falciparum </it>malaria are essential for ensuring effective case management. In Ethiopia, artemether-lumefantrine (AL) has been the first-line treatment for uncomplicated <it>P. falciparum </it>malaria since 2004.</p> <p>Methods</p> <p>Between October and November 2009, we conducted a 42-day, single arm, open label study of AL for <it>P. falciparum </it>in individuals >6 months of age at two sites in Oromia State, Ethiopia. Eligible patients who had documented <it>P. falciparum </it>mono-infection were enrolled and followed according to the standard 2009 World Health Organization <it>in vivo </it>drug efficacy monitoring protocol. The primary and secondary endpoints were PCR uncorrected and corrected cure rates, as measured by adequate clinical and parasitological response on days 28 and 42, respectively.</p> <p>Results</p> <p>Of 4426 patients tested, 120 with confirmed falciparum malaria were enrolled and treated with AL. Follow-up was completed for 112 patients at day 28 and 104 patients at day 42. There was one late parasitological failure, which was classified as undetermined after genotyping. Uncorrected cure rates at both day 28 and 42 for the per protocol analysis were 99.1% (95% CI 95.1-100.0); corrected cure rates at both day 28 and 42 were 100.0%. Uncorrected cure rates at day 28 and 42 for the intention to treat analysis were 93.3% (95% CI 87.2-97.1) and 86.6% (95% CI 79.1-92.1), respectively, while the corrected cure rates at day 28 and 42 were 94.1% (95% CI 88.2-97.6) and 87.3% (95% CI 79.9-92.7), respectively. Using survival analysis, the unadjusted cure rate was 99.1% and 100.0% adjusted by genotyping for day 28 and 42, respectively. Eight <it>P. falciparum </it>patients (6.7%) presented with <it>Plasmodium vivax </it>infection during follow-up and were excluded from the per protocol analysis. Only one patient had persistent parasitaemia at day 3. No serious adverse events were reported, with cough and nausea/vomiting being the most common adverse events.</p> <p>Conclusions</p> <p>AL remains a highly effective and well-tolerated treatment for uncomplicated falciparum malaria in the study setting after several years of universal access to AL. A high rate of parasitaemia with <it>P. vivax </it>possibly from relapse or new infection was observed.</p> <p>Trial Registration</p> <p><a href="http://www.clinicaltrials.gov/ct2/show/NCT01052584">NCT01052584</a></p

Functional overlap of microtubule assembly factors in chromatin-promoted spindle assembly

Author Posting. © American Society for Cell Biology, 2009. This article is posted here by permission of American Society for Cell Biology for personal use, not for redistribution. The definitive version was published in Molecular Biology of the Cell 20 (2009): 2766-2773, doi:10.1091/mbc.E09-01-0043.Distinct pathways from centrosomes and chromatin are thought to contribute in parallel to microtubule nucleation and stabilization during animal cell mitotic spindle assembly, but their full mechanisms are not known. We investigated the function of three proposed nucleation/stabilization factors, TPX2, {gamma}-tubulin and XMAP215, in chromatin-promoted assembly of anastral spindles in Xenopus laevis egg extract. In addition to conventional depletion-add back experiments, we tested whether factors could substitute for each other, indicative of functional redundancy. All three factors were required for microtubule polymerization and bipolar spindle assembly around chromatin beads. Depletion of TPX2 was partially rescued by the addition of excess XMAP215 or EB1, or inhibiting MCAK (a Kinesin-13). Depletion of either {gamma}-tubulin or XMAP215 was partially rescued by adding back XMAP215, but not by adding any of the other factors. These data reveal functional redundancy between specific assembly factors in the chromatin pathway, suggesting individual proteins or pathways commonly viewed to be essential may not have entirely unique functions.This work was supported by the American Cancer Society (grant PF0711401 to T. J. Maresca), the National Cancer Institute (grant CA078048-09 to T. J. Mitchison) and the National Institutes of Health (grant F32GM080049 to J. C. Gatlin and grant GM24364 to E. D. Salmon)

Multiple Insecticide Resistance: An Impediment to Insecticide-Based Malaria Vector Control Program

BACKGROUND: Indoor Residual Spraying (IRS), insecticide-treated nets (ITNs) and long-lasting insecticidal nets (LLINs) are key components in malaria prevention and control strategy. However, the development of resistance by mosquitoes to insecticides recommended for IRS and/or ITNs/LLINs would affect insecticide-based malaria vector control. We assessed the susceptibility levels of Anopheles arabiensis to insecticides used in malaria control, characterized basic mechanisms underlying resistance, and evaluated the role of public health use of insecticides in resistance selection. METHODOLOGY/PRINCIPAL FINDINGS: Susceptibility status of An. arabiensis was assessed using WHO bioassay tests to DDT, permethrin, deltamethrin, malathion and propoxur in Ethiopia from August to September 2009. Mosquito specimens were screened for knockdown resistance (kdr) and insensitive acetylcholinesterase (ace-1(R)) mutations using AS-PCR and PCR-RFLP, respectively. DDT residues level in soil from human dwellings and the surrounding environment were determined by Gas Chromatography with Electron Capture Detector. An. arabiensis was resistant to DDT, permethrin, deltamethrin and malathion, but susceptible to propoxur. The West African kdr allele was found in 280 specimens out of 284 with a frequency ranged from 95% to 100%. Ace-1(R) mutation was not detected in all specimens scored for the allele. Moreover, DDT residues were found in soil samples from human dwellings but not in the surrounding environment. CONCLUSION: The observed multiple-resistance coupled with the occurrence of high kdr frequency in populations of An. arabiensis could profoundly affect the malaria vector control programme in Ethiopia. This needs an urgent call for implementing rational resistance management strategies and integrated vector control intervention

A systematic review of economic analyses of telehealth services using real time video communication

Background: Telehealth is the delivery of health care at a distance, using information and communication technology. The major rationales for its introduction have been to decrease costs, improve efficiency and increase access in health care delivery. This systematic review assesses the economic value of one type of telehealth delivery - synchronous or real time video communication - rather than examining a heterogeneous range of delivery modes as has been the case with previous reviews in this area. Methods A systematic search was undertaken for economic analyses of the clinical use of telehealth, ending in June 2009. Studies with patient outcome data and a non-telehealth comparator were included. Cost analyses, non-comparative studies and those where patient satisfaction was the only health outcome were excluded. Results 36 articles met the inclusion criteria. 22(61%) of the studies found telehealth to be less costly than the non-telehealth alternative, 11(31%) found greater costs and 3 (9%) gave the same or mixed results. 23 of the studies took the perspective of the health services, 12 were societal, and one was from the patient perspective. In three studies of telehealth to rural areas, the health services paid more for telehealth, but due to savings in patient travel, the societal perspective demonstrated cost savings. In regard to health outcomes, 12 (33%) of studies found improved health outcomes, 21 (58%) found outcomes were not significantly different, 2(6%) found that telehealth was less effective, and 1 (3%) found outcomes differed according to patient group. The organisational model of care was more important in determining the value of the service than the clinical discipline, the type of technology, or the date of the study. Conclusion Delivery of health services by real time video communication was cost-effective for home care and access to on-call hospital specialists, showed mixed results for rural service delivery, and was not cost-effective for local delivery of services between hospitals and primary care