Search Results Heading

MBRLSearchResults

mbrl.module.common.modules.added.book.to.shelf
Title added to your shelf!
View what I already have on My Shelf.
Oops! Something went wrong.
Oops! Something went wrong.
While trying to add the title to your shelf something went wrong :( Kindly try again later!
Are you sure you want to remove the book from the shelf?
Oops! Something went wrong.
Oops! Something went wrong.
While trying to remove the title from your shelf something went wrong :( Kindly try again later!
    Done
    Filters
    Reset
  • Discipline
      Discipline
      Clear All
      Discipline
  • Is Peer Reviewed
      Is Peer Reviewed
      Clear All
      Is Peer Reviewed
  • Item Type
      Item Type
      Clear All
      Item Type
  • Subject
      Subject
      Clear All
      Subject
  • Year
      Year
      Clear All
      From:
      -
      To:
  • More Filters
      More Filters
      Clear All
      More Filters
      Source
    • Language
171 result(s) for "Mwangi, James"
Sort by:
Preliminary efficacy of a community health worker homebased intervention for the control and management of hypertension in Kiambu County, Kenya- a randomized control trial
In Sub Saharan Africa, there is a growing burden of non-communicable diseases, which poses a big challenge to the resource-limited health system in these settings. The aim of this study was to determine the feasibility and preliminary efficacy of a community health workers (CHWs) home-based lifestyle interventions to improve blood pressure (BP) control and body composition among hypertensive patients in low-income populations of Kiambu County, Kenya. This was a randomized controlled trial (RCT) involving 80 patients with uncontrolled high BP (systolic BP (SBP) ≥140mmHg and/or diastolic BP (DBP) ≥90) randomized to either a CHW homebased intervention or a usual care (control) arm and followed up for 6 months. The intervention involved monthly CHW home-visits for health education and audits on behavioral risk factors that affect BP. An adapted WHO stepwise questionnaire and international physical activity questionnaire was used to collect data on behavioral cardiovascular risk factors. To assess the main outcomes of BP, body mass index (BMI) and waist-height-ratio (WHtR), a survey was conducted at baseline, 3 months, and 6 months. Data regarding univariate, bivariate and multivariate (repeated measurements between and within groups) analysis at 5% level of significance were analyzed using STATA 18. Generalized estimating equations (GEE) for repeated measures were used to estimate changes in BP, BMI and WHtR, and to examine the association between the CHW intervention and BP control. The study revealed that 77.5% and 92.5% of the participants in usual care and intervention groups completed the follow-up, respectively. After 6 months of follow-up, there was a reduction in the mean SBP and DBP for both arms, and reductions in BMI and WHtR only in the intervention arm. The adjusted mean reduction in SBP (-8.4 mm Hg; 95% CI, -13.4 to -3.3; P = 0.001) and DBP (-5.2 mm Hg 95% CI, -8.3 to -2.0; P<0.001) were significantly higher in the intervention group compared to the control group. The proportion of participants who achieved the controlled BP target of <140/90 mm Hg was 62.2% and 25.8% for the intervention and usual care arm, respectively. The proportion with controlled BP was significantly higher in the intervention arm compared to the usual care arm after adjusting for baseline covariates (AOR 2.8, 95% CI 1.3-6.0, p = 0.008). There was no significant effect of the intervention on BMI and WHtR. A home-based CHW intervention was significantly associated with reduction in BP among hypertensive patients compared to usual care. Future fully powered RCTs to test the effectiveness of such interventions among low-income populations are recommended. Trial registration number: PACTR202309530525257.
Europe as a secondary distribution hub in the worldwide invasion of the potato cyst nematode Globodera rostochiensis
The potato cyst nematode Globodera rostochiensis originates from the Andean Mountain region in South America and has unintentionally been introduced to all inhabited continents. Several studies have examined the population genetic structure of this pest in various countries by using microsatellite markers. However, merging microsatellite data produced from different laboratories is challenging and can introduce uncertainty when interpreting the results. To overcome this challenge and to explore invasion routes of this pest, we have genotyped 22 G. rostochiensis populations from all continents. Within populations, the highest genetic diversity was observed in the South American populations, the European populations showed an intermediate level of genetic diversity and the remaining populations were the less diverse. This confirmed pre-existing knowledge such as a first introduction event from South America to Europe, but the less diverse populations could originate either from South America or from Europe. At the continental scale, STRUCTURE genetic clustering output indicated that North America and Asia have experienced at least two introduction events. Comparing different evolutionary scenarios, the Approximate Bayesian Computation analysis showed that Europe served as a secondary distribution centre for the invasion of G. rostochiensis into all other continents (North America, Africa, Asia and Oceania).
Peptide Toxin Diversity and a Novel Antimicrobial Peptide from the Spider Oxyopes forcipiformis
Spider venoms are emerging as a rich source of bioactive peptide toxins with therapeutic potential. Lynx spiders of the genus Oxyopes are small, cursorial hunters that employ complex venom to subdue arthropod prey. However, extracting crude venom from these diminutive arachnids poses significant challenges. This study presents a transcriptome analysis of venom glands from an undescribed Oxyopes forcipiformis species, revealing 339 putative protein and peptide toxin sequences categorized into seven functional groups. The venom composition was dominated by membrane-active peptides (40.71%), venom auxiliary proteins (22.71%), neurotoxins (15.63%), channel active peptides (7.08%) and uncharacterized components (13.87%). Additionally, phylogenetic analysis of 65 disulfide-bond-rich peptides yielded six distinct families based on sequence homology and cysteine framework. Finally, a novel antimicrobial peptide, GK37, was identified using in silico and homology analyses. Our data suggested that GK37 presented significant antibacterial activity against Gram-positive bacteria Staphylococcus aureus with a minimum inhibitory concentration (MIC) of 1.552 µM by disrupting bacterial membranes. At 4× MICs, GK37 almost showed no hemolytic activity on blood cells or toxicity against Hek293T cells. Our findings provided a basis for targeted studies of the diversity and pharmacological effects of lynx spider peptide. We elucidated a valuable high-throughput approach for obtaining proteins and peptides from small-group spiders.
In Vitro and In Vivo Antimalarial Activity of LZ1, a Peptide Derived from Snake Cathelicidin
Antimalarial drug resistance is an enormous global threat. Recently, antimicrobial peptides (AMPs) are emerging as a new source of antimalarials. In this study, an AMP LZ1 derived from snake cathelicidin was identified with antimalarial activity. In the in vitro antiplasmodial assay, LZ1 showed strong suppression of blood stage Plasmodium falciparum (P. falciparum) with an IC50 value of 3.045 μM. In the in vivo antiplasmodial assay, LZ1 exerted a significant antimalarial activity against Plasmodium berghei (P. berghei) in a dose- and a time- dependent manner. In addition, LZ1 exhibited anti-inflammatory effects and attenuated liver-function impairment during P. berghei infection. Furthermore, by employing inhibitors against glycolysis and oxidative phosphorylation in erythrocytes, LZ1 specifically inhibited adenosine triphosphate (ATP) production in parasite-infected erythrocyte by selectively inhibiting the pyruvate kinase activity. In conclusion, the present study demonstrates that LZ1 is a potential candidate for novel antimalarials development.
Discovery of insect Blaps rhynchopetera Fairmaire extracts with anti-tyrosinase activity and anti-melanin deposition
Fairmaire is a medicinal insect that has been used for a long time by minority ethnic groups in Yunnan, China, due to its immunomodulatory function. However, its potential applications in cosmetics have not been reported. experiments were used to verify whether the extracts of Fairmaire (EBR) have the effect of inhibiting TYR activity and eliminating melanin deposition. Subsequently, experiments were conducted to verify further the potential application of the EBR in whitening. To explore the whitening components of the EBR, we employed UHPLC-Q-TOF MS to identify the compounds present in the EBR and utilized network pharmacology to compare them with the genes involved in whitening in the database, thereby obtaining the intersection of compound targets and whitening targets. Then, protein-protein interaction network analysis, gene ontology enrichment and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis were carried out to explore the main components of the whitening effect of the EBR. Further, molecular docking and molecular dynamics simulation were used to verify the correlation between the main components of the EBR and the essential target molecules. and studies have found that the EBR exhibits anti-oxidation, TYR-inhibiting activity, and the elimination of melanin deposition. Subsequently, 1538 metabolites were identified by UHPLC-Q-TOF MS analysis, indicating that EBR is a rich source of bioactive compounds. Among them, 82 kinds of phenols and flavonoids may be derived from external enrichment or self-synthesis. Network pharmacology revealed 41 genes related to pigmentation and TYR inhibition. Molecular docking and molecular dynamics simulation confirmed that myricetin, luteolin, apigenin and quercetin have a high binding affinity with TYR, which may regulate melanin production by inhibiting TYR activity. In this study, we identified the primary whitening active ingredients of and utilized network pharmacology and molecular dynamics simulation to investigate the mechanism underlying the whitening effect of EBR. This work reveals that insect extraction may have broad application prospects in the preparation of cosmetics. To our knowledge, this is the first report identifying the flavonoids quercetin, luteolin, myricetin, and apigenin as whitening-active components in insects.
Isolation and Characterization of Poecistasin, an Anti-Thrombotic Antistasin-Type Serine Protease Inhibitor from Leech Poecilobdella manillensis
Antistasin, first identified as a potent inhibitor of the blood coagulation factor Xa, is a novel family of serine protease inhibitors. In this study, we purified a novel antistasin-type inhibitor from leech Poecilobdella manillensis called poecistasin. Amino acid sequencing of this 48-amino-acid protein revealed that poecistasin was an antistasin-type inhibitor known to consist of only one domain. Poecistasin inhibited factor XIIa, kallikrein, trypsin, and elastase, but had no inhibitory effect on factor Xa and thrombin. Poecistasin showed anticoagulant activities. It prolonged the activated partial thromboplastin time and inhibited FeCl3-induced carotid artery thrombus formation, implying its potent function in helping Poecilobdella manillensis to take a blood meal from the host by inhibiting coagulation. Poecistasin also suppressed ischemic stroke symptoms in transient middle cerebral artery occlusion mice model. Our results suggest that poecistasin from the leech Poecilobdella manillensis plays a crucial role in blood-sucking and may be an excellent candidate for the development of clinical anti-thrombosis and anti-ischemic stroke medicines.
LCTX-F2, a Novel Potentiator of Coagulation Factors From the Spider Venom of Lycosa singoriensis
Spider venoms contain many functional proteins/peptides such as proteinases, serine/cysteine proteinase inhibitors, insecticidal toxins, and ion channel toxins. However, to date, no peptide toxin with procoagulant activities has been identified from spider venom. In this study, a novel toxin LCTX-F2 with coagulation-promoting activity was identified and characterized in the venom of the spider ( ). LCTX-F2 significantly shortened activated partial thromboplastin time (APTT), clotting time, and plasma recalcification time. This toxin directly interacted with several coagulation factors such as FXIIa, kallikrein, thrombin, and FXa and increased their protease activities. In liver bleeding and tail bleeding mouse models, LCTX-F2 significantly decreased the number of blood cells and bleeding time in a dose-dependent manner. At the same dosage, LCTX-F2 exhibited a more significant procoagulant effect than epsilon aminocaproic acid (EACA). Moreover, LCTX-F2 showed no cytotoxic or hemolytic activity against either normal cells or red blood cells. Our results suggested that LCTX-F2 is a potentiator of coagulation factors with the potential for use in the development of procoagulant drugs.
An Antiviral Peptide from Alopecosa nagpag Spider Targets NS2B–NS3 Protease of Flaviviruses
Flaviviruses are single-stranded RNA viruses predominantly transmitted by the widely distributed Aedes mosquitoes in nature. As important human pathogens, the geographic reach of Flaviviruses and their threats to public health are increasing, but there is currently no approved specific drug for treatment. In recent years, the development of peptide antivirals has gained much attention. Natural host defense peptides which uniquely evolved to protect the hosts have been shown to have antiviral properties. In this study, we firstly collected the venom of the Alopecosa nagpag spider from Shangri-La County, Yunnan Province. A defense peptide named Av-LCTX-An1a (Antiviral-Lycotoxin-An1a) was identified from the spider venom, and its anti-dengue serotype-2 virus (DENV2) activity was verified in vitro. Moreover, a real-time fluorescence-based protease inhibition assay showed that An1a functions as a DENV2 NS2B–NS3 protease inhibitor. Furthermore, we also found that An1a restricts zika virus (ZIKV) infection by inhibiting the ZIKV NS2B–NS3 protease. Together, our findings not only demonstrate that An1a might be a candidate for anti-flavivirus drug but also indicate that spider venom is a potential resource library rich in antiviral precursor molecules.
Snake C-Type Lectins Potentially Contribute to the Prey Immobilization in Protobothrops mucrosquamatus and Trimeresurus stejnegeri Venoms
Snake venoms contain components selected to immobilize prey. The venoms from Elapidae mainly contain neurotoxins, which are critical for rapid prey paralysis, while the venoms from Viperidae and Colubridae may contain fewer neurotoxins but are likely to induce circulatory disorders. Here, we show that the venoms from Protobothrops mucrosquamatus and Trimeresurus stejnegeri are comparable to those of Naja atra in prey immobilization. Further studies indicate that snake C-type lectin-like proteins (snaclecs), which are one of the main nonenzymatic components in viper venoms, are responsible for rapid prey immobilization. Snaclecs (mucetin and stejnulxin) from the venoms of P. mucrosquamatus and T. stejnegeri induce the aggregation of both mammalian platelets and avian thrombocytes, leading to acute cerebral ischemia, and reduced animal locomotor activity and exploration in the open field test. Viper venoms in the absence of snaclecs fail to aggregate platelets and thrombocytes, and thus show an attenuated ability to cause cerebral ischemia and immobilization of their prey. This work provides novel insights into the prey immobilization mechanism of Viperidae snakes and the understanding of viper envenomation-induced cerebral infarction.
Fused Filament Fabrication of Recycled HDPE and Cactus Composite as a Biobased Material
Plastic pollution has emerged as a significant global issue, highlighting the need for sustainable alternatives and effective recycling methods. Concurrently, the cactus plant offers a promising source of bio‐based materials, particularly due to its resilience in harsh environments. This study focused on the performance characterization of cactus powder mixed with recycled high‐density polyethylene (rHDPE) pellets for filament production suitable for 3D printing using the Fused Filament Fabrication method. The physical properties of both cactus and rHDPE were investigated, and composite filaments were prepared from 5%, 10%, and 15% cactus powder alongside rHDPE. Performance evaluation of the composite filaments was conducted using a Universal Testing Machine. Additionally, the chemical composition of cactus powder was analyzed, and the particle size distribution was determined. The combination of HDPE pellets and cactus powder yielded a viable filament, though increasing proportions of cactus reduced the extrusion properties. The tensile strength of pure rHDPE filament was measured at 16.27 MPa, while the tensile strengths for the 5% and 10% cactus composites were 14.97 and 10.74 MPa, respectively. For the printed specimens, the tensile strength was recorded at 13.04 MPa for rHDPE and 8.28 MPa for the 5% cactus composite. The flexural strength results showed 21.77 MPa for rHDPE and 15.64 MPa for the 5% cactus composite. These findings suggest that cactus powder can serve as a valuable additive in developing sustainable 3D printing materials. This study explores the integration of cactus powder with recycled HDPE to develop 3D‐printable bio‐composite filaments. Results show that cactus powder can be incorporated up to 10% to allow better printability while enhancing sustainability. The study provides insights into optimizing material formulations for eco‐friendly additive manufacturing applications.