4,931 research outputs found

    Synthesis and neuropharmacological activity of some quinoxalinone derivatives

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    Eight quinoxalinone derivatives were synthesized and investigated for some neuropharmacological effects (analgesia, sedation, convulsion, anxiety, memory and psychosis) in mice and rats. In the CNSdepressant activity, N,N-dibenzyl-2,3-dioxo-1,2,3,4-tetrahydroquinoxaline-6-sulfonamide is the mostactive, while the other compounds appear variously dose-dependent. Only three of the compounds showed anxiolytic effect, with N,N-dibenzyl-2,3-dioxo-1,2,3,4-tetrahydroquinoxaline-6-sulfonamideshowing the highest activity at 2.5 mg/kg. At the dose of 30 mg/kg, 6-nitro-1,4-dihydroquinoxaline-2,3-dione showed a better anxiolytic effect in mice than diazepam (dose: 1 mg/kg), while 1,2,3,4-tetrahydroquinoxaline-2,3-dione (dose: 25 mg/kg) showed a comparative effect to diazepam. 6-Chloro-1,4-dihydro-quinoxaline-2,3-dione and N,N-dibenzyl-2,3-dioxo-1,2,3,4-tetrahydroquinoxaline-6-sulfonamideshowed significant anticonvulsant action. None of the compounds showed any analgesic or antidopaminergiceffect. The LD50 (24 h) calculated for the compounds were between 74 and 160 mg/kg i.p

    Electromyoneurography and laboratory findings in a case of Guillain-Barré syndrome after second dose of Pfizer COVID-19 vaccine

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    Guillain-Barre syndrome (GBS) is an acute immune-mediated disease of the peripheral nerves and nerve roots (polyradiculoneuropathy) that is usually elicited by various infections. We present a case of GBS after receiving the second dose of Pfizer-COVID 19 vaccine. Diagnosis was made after performing an accurate clinical examination, electromyoneurography and laboratory tests. In particular, anti-ganglioside antibo-dies have tested positive. During this pandemic with ongoing worldwide mass vaccination campaign, it is critically important for clinicians to rapidly recognize neurological complications or other side effects associated with COVID-19 vaccinatio

    Prevalence of ototoxicity in University of Benin Teaching Hospital, Benin city: A 5.year review

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    Background: Ototoxicity refers to damage of the cochlea and/or vestibular apparatus from exposure to chemical substances, resulting in hearing impairment and or disequilibrium. An earlier study carried out at University of Benin Teaching Hospital (UBTH) in 2000 implicated chloramphenicol as the commonest ototoxic drug, followed by antimalarials (Quinine).Aim: To identify the commonly implicated drugs in patients diagnosed with ototoxicity in Ear, Nose and Throat (ENT) Clinic of UBTH.Materials and Methods: One.hundred and three patientsf case notes, diagnosed as having ototoxicity, between June 2005 and July 2010 at the ENT Clinic of UBTH were reviewed. Seventy.nine cases met the criteria for diagnosis of ototoxicity in this study.Results: Intravenous quinine (19.0%) was the commonest implicated drug, followed by oral chloroquine (6.3%), antihypertensive drugs (nifedipine, moduretics, artenolol [6.3%]), native herbal medicine (13.9%), chloramphenicol (1.3%), and unidentifiable drugs accounted for 53.2%. Most patients had severe to profound hearing loss at 4000 Hzand at 8000 Hz. Tinnitus was found in 84.8% of the patients.Conclusion: Quinine is still the commonest implicated ototoxic drug in this part of the country

    Antibiotic Resistant Salmonella And Escherichia Coli Isolated From Day-Old Chicks, Vom, Nigeria

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    Reports of large scale mortality of day-old-chicks were received at the National Veterinary Research Institute, Vom, Nigeria in 2007 to 2008. We investigated the cause of death using several virological and bacteriological techniques, isolated the pathogenic agents and carried out sensitivity tests. Our investigation revealed that Escherichia coli and Salmonella organisms were isolated in the outbreaks. A pattern of antibiotic resistance that seems to be increasing was also found. Considering the role of chickens and its products in the human food chain in Nigeria; and the close interaction between poultry and man, these resistant organisms may pose dangers to humans through the food chain or zoonotic infection and precipitate a similar pattern of resistance in man. We advocated for informed use of antibiotics in the food animals, especially poultry

    Hyperuricaemia in obese Type 2 diabetics in Jos, north central Nigeria

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    Introduction: Uric acid is a metabolite from the breakdown of purines. Elevated serum levels (hyperuricaemia) is known to have an association with cardiovascular risk factors that are often seen in obesity, such as hypertension, dyslipidaemia and glucose intolerance. This study will attempt to give an insight into this association among individuals with Type 2 Diabetes mellitus.Methodology: 100 patients with Type 2 diabetes visiting a private health facility in Jos, North Central Nigeria participated in this study. The data obtained for analysis from each participant were anthropometric indices ( body mass index, waist circumference) and laboratory parameters ( serum lipids and uric acid).Results: 64% of participants were males. 79% of the population were obese and 45% had hyperuricaemia. The proportion of females with obesity (94,4%) was significantly greater than that for males (70.3%) but there was no significant difference between the proportion of males and females with hyperuricaemia. Serum uric acid showed significant positive correlation with waist circumference (p=0.04) and age (p=0.03) and had no significant relationship with other variables.Conclusion: Early detection and treatment of hyperuricaemia in obese patients will help reduce their overall risk of cardiovascular events. This is achieved by both non pharmacological and pharmacological means.Key words: Diabetes, Hyperuricaemia, Obesit

    Comparative Field Evaluation of Combinations of Long-Lasting Insecticide Treated Nets and Indoor Residual Spraying, Relative to Either Method Alone, for Malaria Prevention in an Area where the main Vector is Anopheles Arabiensis.

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    Long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) are commonly used together in the same households to improve malaria control despite inconsistent evidence on whether such combinations actually offer better protection than nets alone or IRS alone. Comparative tests were conducted using experimental huts fitted with LLINs, untreated nets, IRS plus untreated nets, or combinations of LLINs and IRS, in an area where Anopheles arabiensis is the predominant malaria vector species. Three LLIN types, Olyset®, PermaNet 2.0® and Icon Life® nets and three IRS treatments, pirimiphos-methyl, DDT, and lambda cyhalothrin, were used singly or in combinations. We compared, number of mosquitoes entering huts, proportion and number killed, proportions prevented from blood-feeding, time when mosquitoes exited the huts, and proportions caught exiting. The tests were done for four months in dry season and another six months in wet season, each time using new intact nets. All the net types, used with or without IRS, prevented >99% of indoor mosquito bites. Adding PermaNet 2.0® and Icon Life®, but not Olyset® nets into huts with any IRS increased mortality of malaria vectors relative to IRS alone. However, of all IRS treatments, only pirimiphos-methyl significantly increased vector mortality relative to LLINs alone, though this increase was modest. Overall, median mortality of An. arabiensis caught in huts with any of the treatments did not exceed 29%. No treatment reduced entry of the vectors into huts, except for marginal reductions due to PermaNet 2.0® nets and DDT. More than 95% of all mosquitoes were caught in exit traps rather than inside huts. Where the main malaria vector is An. arabiensis, adding IRS into houses with intact pyrethroid LLINs does not enhance house-hold level protection except where the IRS employs non-pyrethroid insecticides such as pirimiphos-methyl, which can confer modest enhancements. In contrast, adding intact bednets onto IRS enhances protection by preventing mosquito blood-feeding (even if the nets are non-insecticidal) and by slightly increasing mosquito mortality (in case of LLINs). The primary mode of action of intact LLINs against An. arabiensis is clearly bite prevention rather than insecticidal activity. Therefore, where resources are limited, priority should be to ensure that everyone at risk consistently uses LLINs and that the nets are regularly replaced before being excessively torn. Measures that maximize bite prevention (e.g. proper net sizes to effectively cover sleeping spaces, stronger net fibres that resist tears and burns and net use practices that preserve net longevity), should be emphasized

    Mathematical Evaluation of Community Level Impact of Combining Bed Nets and Indoor Residual Spraying upon Malaria Transmission in Areas where the main Vectors are Anopheles Arabiensis Mosquitoes.

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    Indoor residual insecticide spraying (IRS) and long-lasting insecticide treated nets (LLINs) are commonly used together even though evidence that such combinations confer greater protection against malaria than either method alone is inconsistent. A deterministic model of mosquito life cycle processes was adapted to allow parameterization with results from experimental hut trials of various combinations of untreated nets or LLINs (Olyset, PermaNet 2.0, Icon Life nets) with IRS (pirimiphos methyl, lambda cyhalothrin, DDT), in a setting where vector populations are dominated by Anopheles arabiensis, so that community level impact upon malaria transmission at high coverage could be predicted. Intact untreated nets alone provide equivalent personal protection to all three LLINs. Relative to IRS plus untreated nets, community level protection is slightly higher when Olyset or PermaNet 2.0 nets are added onto IRS with pirimiphos methyl or lambda cyhalothrin but not DDT, and when Icon Life nets supplement any of the IRS insecticides. Adding IRS onto any net modestly enhances communal protection when pirimiphos methyl is sprayed, while spraying lambda cyhalothrin enhances protection for untreated nets but not LLINs. Addition of DDT reduces communal protection when added to LLINs. Where transmission is mediated primarily by An. arabiensis, adding IRS to high LLIN coverage provides only modest incremental benefit (e.g. when an organophosphate like pirimiphos methyl is used), but can be redundant (e.g. when a pyrethroid like lambda cyhalothin is used) or even regressive (e.g. when DDT is used for the IRS). Relative to IRS plus untreated nets, supplementing IRS with LLINs will only modestly improve community protection. Beyond the physical protection that intact nets provide, additional protection against transmission by An. arabiensis conferred by insecticides will be remarkably small, regardless of whether they are delivered as LLINs or IRS. The insecticidal action of LLINs and IRS probably already approaches their absolute limit of potential impact upon this persistent vector so personal protection of nets should be enhanced by improving the physical integrity and durability. Combining LLINs and non-pyrethroid IRS in residual transmission systems may nevertheless be justified as a means to manage insecticide resistance and prevent potential rebound of not only An. arabiensis, but also more potent, vulnerable and historically important species such as Anopheles gambiae and Anopheles funestus

    Dressed States Approach to Quantum Systems

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    Using the non-perturbative method of {\it dressed} states previously introduced in JPhysA, we study effects of the environment on a quantum mechanical system, in the case the environment is modeled by an ensemble of non interacting harmonic oscillators. This method allows to separate the whole system into the {\it dressed} mechanical system and the {\it dressed} environment, in terms of which an exact, non-perturbative approach is possible. When applied to the Brownian motion, we give explicit non-perturbative formulas for the classical path of the particle in the weak and strong coupling regimes. When applied to study atomic behaviours in cavities, the method accounts very precisely for experimentally observed inhibition of atomic decay in small cavities PhysLA, physics0111042

    In Vivo Time- Resolved Microtomography Reveals the Mechanics of the Blowfly Flight Motor

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    Dipteran flies are amongst the smallest and most agile of flying animals. Their wings are driven indirectly by large power muscles, which cause cyclical deformations of the thorax that are amplified through the intricate wing hinge. Asymmetric flight manoeuvres are controlled by 13 pairs of steering muscles acting directly on the wing articulations. Collectively the steering muscles account for <3% of total flight muscle mass, raising the question of how they can modulate the vastly greater output of the power muscles during manoeuvres. Here we present the results of a synchrotron-based study performing micrometre-resolution, time-resolved microtomography on the 145 Hz wingbeat of blowflies. These data represent the first four-dimensional visualizations of an organism's internal movements on sub-millisecond and micrometre scales. This technique allows us to visualize and measure the three-dimensional movements of five of the largest steering muscles, and to place these in the context of the deforming thoracic mechanism that the muscles actuate. Our visualizations show that the steering muscles operate through a diverse range of nonlinear mechanisms, revealing several unexpected features that could not have been identified using any other technique. The tendons of some steering muscles buckle on every wingbeat to accommodate high amplitude movements of the wing hinge. Other steering muscles absorb kinetic energy from an oscillating control linkage, which rotates at low wingbeat amplitude but translates at high wingbeat amplitude. Kinetic energy is distributed differently in these two modes of oscillation, which may play a role in asymmetric power management during flight control. Structural flexibility is known to be important to the aerodynamic efficiency of insect wings, and to the function of their indirect power muscles. We show that it is integral also to the operation of the steering muscles, and so to the functional flexibility of the insect flight motor
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