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Search Results: 1 - 10 of 462319 matches for " Alyson A. Kelvin "
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Comparative Analyses of Pandemic H1N1 and Seasonal H1N1, H3N2, and Influenza B Infections Depict Distinct Clinical Pictures in Ferrets
Stephen S. H. Huang,David Banner,Yuan Fang,Derek C. K. Ng,Thirumagal Kanagasabai,David J. Kelvin,Alyson A. Kelvin
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0027512
Abstract: Influenza A and B infections are a worldwide health concern to both humans and animals. High genetic evolution rates of the influenza virus allow the constant emergence of new strains and cause illness variation. Since human influenza infections are often complicated by secondary factors such as age and underlying medical conditions, strain or subtype specific clinical features are difficult to assess. Here we infected ferrets with 13 currently circulating influenza strains (including strains of pandemic 2009 H1N1 [H1N1pdm] and seasonal A/H1N1, A/H3N2, and B viruses). The clinical parameters were measured daily for 14 days in stable environmental conditions to compare clinical characteristics. We found that H1N1pdm strains had a more severe physiological impact than all season strains where pandemic A/California/07/2009 was the most clinically pathogenic pandemic strain. The most serious illness among seasonal A/H1N1 and A/H3N2 groups was caused by A/Solomon Islands/03/2006 and A/Perth/16/2009, respectively. Among the 13 studied strains, B/Hubei-Wujiagang/158/2009 presented the mildest clinical symptoms. We have also discovered that disease severity (by clinical illness and histopathology) correlated with influenza specific antibody response but not viral replication in the upper respiratory tract. H1N1pdm induced the highest and most rapid antibody response followed by seasonal A/H3N2, seasonal A/H1N1 and seasonal influenza B (with B/Hubei-Wujiagang/158/2009 inducing the weakest response). Our study is the first to compare the clinical features of multiple circulating influenza strains in ferrets. These findings will help to characterize the clinical pictures of specific influenza strains as well as give insights into the development and administration of appropriate influenza therapeutics.
Influenza Transmission in the Mother-Infant Dyad Leads to Severe Disease, Mammary Gland Infection, and Pathogenesis by Regulating Host Responses
Stéphane G. Paquette?,David Banner?,Stephen S. H. Huang?,Raquel Almansa?,Alberto Leon?,Luoling Xu?,Jessica Bartoszko?,David J. Kelvin,Alyson A. Kelvin
PLOS Pathogens , 2015, DOI: 10.1371/journal.ppat.1005173
Abstract: Seasonal influenza viruses are typically restricted to the human upper respiratory tract whereas influenza viruses with greater pathogenic potential often also target extra-pulmonary organs. Infants, pregnant women, and breastfeeding mothers are highly susceptible to severe respiratory disease following influenza virus infection but the mechanisms of disease severity in the mother-infant dyad are poorly understood. Here we investigated 2009 H1N1 influenza virus infection and transmission in breastfeeding mothers and infants utilizing our developed infant-mother ferret influenza model. Infants acquired severe disease and mortality following infection. Transmission of the virus from infants to mother ferrets led to infection in the lungs and mother mortality. Live virus was also found in mammary gland tissue and expressed milk of the mothers which eventually led to milk cessation. Histopathology showed destruction of acini glandular architecture with the absence of milk. The virus was localized in mammary epithelial cells of positive glands. To understand the molecular mechanisms of mammary gland infection, we performed global transcript analysis which showed downregulation of milk production genes such as Prolactin and increased breast involution pathways indicated by a STAT5 to STAT3 signaling shift. Genes associated with cancer development were also significantly increased including JUN, FOS and M2 macrophage markers. Immune responses within the mammary gland were characterized by decreased lymphocyte-associated genes CD3e, IL2Ra, CD4 with IL1β upregulation. Direct inoculation of H1N1 into the mammary gland led to infant respiratory infection and infant mortality suggesting the influenza virus was able to replicate in mammary tissue and transmission is possible through breastfeeding. In vitro infection studies with human breast cells showed susceptibility to H1N1 virus infection. Together, we have shown that the host-pathogen interactions of influenza virus infection in the mother-infant dyad initiate immunological and oncogenic signaling cascades within the mammary gland. These findings suggest the mammary gland may have a greater role in infection and immunity than previously thought.
Inflammatory Cytokine Expression Is Associated with Chikungunya Virus Resolution and Symptom Severity
Alyson A. Kelvin ,David Banner,Giuliano Silvi,Maria Luisa Moro,Nadir Spataro,Paolo Gaibani,Francesca Cavrini,Anna Pierro,Giada Rossini,Mark J. Cameron,Jesus F. Bermejo-Martin,Stéphane G. Paquette,Luoling Xu,Ali Danesh,Amber Farooqui,Ilaria Borghetto,David J. Kelvin,Vittorio Sambri,Salvatore Rubino
PLOS Neglected Tropical Diseases , 2011, DOI: 10.1371/journal.pntd.0001279
Abstract: The Chikungunya virus infection zones have now quickly spread from Africa to parts of Asia, North America and Europe. Originally thought to trigger a disease of only mild symptoms, recently Chikungunya virus caused large-scale fatalities and widespread economic loss that was linked to recent virus genetic mutation and evolution. Due to the paucity of information on Chikungunya immunological progression, we investigated the serum levels of 13 cytokines/chemokines during the acute phase of Chikungunya disease and 6- and 12-month post-infection follow-up from patients of the Italian outbreak. We found that CXCL9/MIG, CCL2/MCP-1, IL-6 and CXCL10/IP-10 were significantly raised in the acute phase compared to follow-up samples. Furthermore, IL-1β, TNF-α, Il-12, IL-10, IFN-γ and IL-5 had low initial acute phase levels that significantly increased at later time points. Analysis of symptom severity showed association with CXCL9/MIG, CXCL10/IP-10 and IgG levels. These data give insight into Chikungunya disease establishment and subsequent convalescence, which is imperative to the treatment and containment of this quickly evolving and frequently re-emerging disease.
Lack of Innate Interferon Responses during SARS Coronavirus Infection in a Vaccination and Reinfection Ferret Model
Mark J. Cameron, Alyson A. Kelvin, Alberto J. Leon, Cheryl M. Cameron, Longsi Ran, Luoling Xu, Yong-Kyu Chu, Ali Danesh, Yuan Fang, Qianjun Li, Austin Anderson, Ronald C. Couch, Stephane G. Paquette, Ndingsa G. Fomukong, Otfried Kistner, Manfred Lauchart, Thomas Rowe, Kevin S. Harrod, Colleen B. Jonsson, David J. Kelvin
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0045842
Abstract: In terms of its highly pathogenic nature, there remains a significant need to further define the immune pathology of SARS-coronavirus (SARS-CoV) infection, as well as identify correlates of immunity to help develop vaccines for severe coronaviral infections. Here we use a SARS-CoV infection-reinfection ferret model and a functional genomics approach to gain insight into SARS immunopathogenesis and to identify correlates of immune protection during SARS-CoV-challenge in ferrets previously infected with SARS-CoV or immunized with a SARS virus vaccine. We identified gene expression signatures in the lungs of ferrets associated with primary immune responses to SARS-CoV infection and in ferrets that received an identical second inoculum. Acute SARS-CoV infection prompted coordinated innate immune responses that were dominated by antiviral IFN response gene (IRG) expression. Reinfected ferrets, however, lacked the integrated expression of IRGs that was prevalent during acute infection. The expression of specific IRGs was also absent upon challenge in ferrets immunized with an inactivated, Al(OH)3-adjuvanted whole virus SARS vaccine candidate that protected them against SARS-CoV infection in the lungs. Lack of IFN-mediated immune enhancement in infected ferrets that were previously inoculated with, or vaccinated against, SARS-CoV revealed 9 IRG correlates of protective immunity. This data provides insight into the molecular pathogenesis of SARS-CoV and SARS-like-CoV infections and is an important resource for the development of CoV antiviral therapeutics and vaccines.
Case Report: Osteochondral Fragment—A Rare Cause of Locked Metacarpophalangeal Joint  [PDF]
Kelvin Ramsey, S. Overstall, A. Fleming
Surgical Science (SS) , 2011, DOI: 10.4236/ss.2011.26076
Abstract: We describe the presentation of a patient with sudden, sharp pain associated with a snapping sensation, swelling and pain over the metacarpophalangeal joint (MCPJ) with no history of direct trauma. The finger was held in 30 degrees of flexion and significantly deviated to the ulnar side with loss of extension. A diagnosis of traumatic rupture of the radial sagittal band of the extensor mechanism was made but the cause at exploration was found to be impingement of an osteochondral fracture fragment. This is a rare cause of irreducible loose body ‘locking’ of the metacarpophalangeal joint.
The Potential of Common Beneficial Insects and Strategies for Maintaining Them in Bean Fields of Sub Saharan Africa  [PDF]
Baltazar Ndakidemi, Kelvin Mtei, Patrick A Ndakidemi
American Journal of Plant Sciences (AJPS) , 2016, DOI: 10.4236/ajps.2016.73036
Abstract: Beneficial insects provide natural ecosystem services such as biological control of pests, soil formation, nutrient cycling and pollination of plants. Beneficial insects include pollinators important in the essential pollination process of all plants, and natural enemies of pests such as parasitoids and predators which are important in the suppression of pest damage to crops. Knowledge on management techniques to attract beneficial insects in the agricultural fields is a way forward to enhance agro ecosystems for increased crop production. Therefore, proper understanding and identification of natural enemies, as well as pollinators in agricultural fields, is essential in promoting biological control and pollination activity. Natural enemies and pollinators, within legume fields, play a key role in ensuring sustainable production, especially in smallholder farms. There is a limited understanding of beneficial insects and the ecosystem services they offer to the agricultural production process in much of sub-Saharan Africa. This paper reviewed and provided existing knowledge on beneficial insects in bean fields. This will give the basis for research on beneficial insects in bean fields and practices that encourage their populations.
Impacts of Synthetic and Botanical Pesticides on Beneficial Insects  [PDF]
Baltazar Ndakidemi, Kelvin Mtei, Patrick A. Ndakidemi
Agricultural Sciences (AS) , 2016, DOI: 10.4236/as.2016.76038
Abstract: Sustainable methods to control insect pests that affect crop yield have become a great challenge to mainly smallholder farmers. Beneficial insects in agricultural fields play an important role in natural pest control and pollination. The use of synthetic and botanical pesticides has detrimental effects to both natural enemies and pollinators in agricultural fields. The pesticides affect the survival of a range of life cycle stages, reductions in reproductive capacity, changes in the suitability of hosts for parasitising or predation, reduced emergence of parasitoids from sprayed host eggs and cause direct mortality. This has caused a serious menace to biological control agents and pollinators. When natural enemies are reduced, even more serious consequences may result for pest population dynamics which include the phenomena of resurgence and eruption of secondary pests. The decrease in pollinators reduces agricultural productivity. This review aims at exploring the side effects of synthetic and botanical pesticides on beneficial insects to give the basis for research on the negative impacts of synthetic and botanical pesticides on these insects. This information will assist in optimizing the use of pesticides in integrated pest management programmes by employing more sustainable and ecosystem benign practices such as the use of right dosage and selective pesticides in agricultural fields.
Isolation and Molecular Characterization of Elite Indigenous Rhizobia Nodulating Phaseolus bean (Phaseolus vulgaris L.)  [PDF]
Yusuph Namkeleja, Kelvin Mtei, Patrick A. Ndakidemi
American Journal of Plant Sciences (AJPS) , 2016, DOI: 10.4236/ajps.2016.714175
Abstract: Nowadays application of biological nitrogen fixation (BNF) through rhizobia inoculums is highly promoted as a solution to solve the problem of poor soil fertility in areas where legumes are cultivated. This is due to the fact that, rhizobia enhance nitrogen fixation, induce disease resistance, reduce heavy metal in the soil, facilitate bioavailabity of iron in soil and is environmental friendly. To get rhizobia strains which are suitable for inoculants production, isolation and molecular characterization of elite rhizobia are highly needed. Molecular characterization acts as a spark plug for discovery of many microbes including Rhizobia. Multi Locus Sequence Analysis (MLSA), 16S rRNA gene sequence analysis, DNA-DNA hybridization and SDS-PAGE analysis of the whole-cell proteins are the molecular techniques mostly used in characterizing rhizobia. But before deciding to use or not to use rhizobia inoculants in certain areas, knowing the population size of indigenous rhizobia found in that area is very important, because this is a major factor which determines inoculums responses as well gives clues on which areas need or do not need inoculation. The Most Probable Number (MPN) method is mostly used in enumerating rhizobia population of the soil. Given that, in most of the developing countries, including Tanzania, Biological Nitrogen Fixation (BNF) technology is not fully flourished; more efforts in isolation, molecular characterization of elite rhizobia and estimation of indigenous rhizobia population in various areas are required.
Interleukin-6 Is a Potential Biomarker for Severe Pandemic H1N1 Influenza A Infection
Stéphane G. Paquette, David Banner, Zhen Zhao, Yuan Fang, Stephen S. H. Huang, Alberto J. Le?n, Derek C. K. Ng, Raquel Almansa, Ignacio Martin-Loeches, Paula Ramirez, Lorenzo Socias, Ana Loza, Jesus Blanco, Paola Sansonetti, Jordi Rello, David Andaluz, Bianche Shum, Salvatore Rubino, Raul Ortiz de Lejarazu, Dat Tran, Giovanni Delogu, Giovanni Fadda, Sigmund Krajden, Barry B. Rubin, Jesús F. Bermejo-Martin, Alyson A. Kelvin, David J. Kelvin
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0038214
Abstract: Pandemic H1N1 influenza A (H1N1pdm) is currently a dominant circulating influenza strain worldwide. Severe cases of H1N1pdm infection are characterized by prolonged activation of the immune response, yet the specific role of inflammatory mediators in disease is poorly understood. The inflammatory cytokine IL-6 has been implicated in both seasonal and severe pandemic H1N1 influenza A (H1N1pdm) infection. Here, we investigated the role of IL-6 in severe H1N1pdm infection. We found IL-6 to be an important feature of the host response in both humans and mice infected with H1N1pdm. Elevated levels of IL-6 were associated with severe disease in patients hospitalized with H1N1pdm infection. Notably, serum IL-6 levels associated strongly with the requirement of critical care admission and were predictive of fatal outcome. In C57BL/6J, BALB/cJ, and B6129SF2/J mice, infection with A/Mexico/4108/2009 (H1N1pdm) consistently triggered severe disease and increased IL-6 levels in both lung and serum. Furthermore, in our lethal C57BL/6J mouse model of H1N1pdm infection, global gene expression analysis indicated a pronounced IL-6 associated inflammatory response. Subsequently, we examined disease and outcome in IL-6 deficient mice infected with H1N1pdm. No significant differences in survival, weight loss, viral load, or pathology were observed between IL-6 deficient and wild-type mice following infection. Taken together, our findings suggest IL-6 may be a potential disease severity biomarker, but may not be a suitable therapeutic target in cases of severe H1N1pdm infection due to our mouse data.
Prospective Bioactive Compounds from Vernonia amygdalina, Lippia javanica, Dysphania ambrosioides and Tithonia diversifolia in Controlling Legume Insect Pests  [PDF]
Regina W. Mwanauta, Kelvin A. Mtei, Patrick A. Ndakidemi
Agricultural Sciences (AS) , 2014, DOI: 10.4236/as.2014.512123
Abstract: Synthetic insecticides are widely known to control insect pest, but due to high operational cost, environmental pollution, toxicity to humans, harmful effect on non-target organisms and the development of insect resistance to this products, have created the need for developing alternative such as those involving the use of botanical pesticides to control insect pest. Bioactive compounds derived from plant could be an alternative source for insect pest control because they constitute a rich source of natural chemicals. This review aims to explore the potential of plant bioactive compounds from Vernonia amygdalina, Lippia javanica, Dysphania ambrosioides and Tithonia diversifolia as a low-cost, safe and environmentally friendly means of controlling insect pests in legumes.
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