11 results on '"Kamau Y"'
Search Results
2. Crystal Structure of the large terminase subunit gp2 of bacterial virus Sf6 complexed with ATP-r-S
- Author
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Zhao, H., primary, Christensen, T., additional, Kamau, Y., additional, and Tang, L., additional
- Published
- 2013
- Full Text
- View/download PDF
3. Crystal Structure of the large terminase subunit gp2 of bacterial virus Sf6 complexed with ADP
- Author
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Zhao, H., primary, Christensen, T., additional, Kamau, Y., additional, and Tang, L., additional
- Published
- 2013
- Full Text
- View/download PDF
4. Crystal Structure of the large terminase subunit gp2 of bacterial virus Sf6
- Author
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Zhao, H., primary, Christensen, T., additional, Kamau, Y., additional, and Tang, L., additional
- Published
- 2013
- Full Text
- View/download PDF
5. Mosquitocidal efficacy and pharmacokinetics of single-dose ivermectin versus three-day dose regimen for malaria vector control compared with albendazole and no treatment: An open-label randomized controlled trial.
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Kamau Y, Tuwei M, Wanjiku C, Ominde K, Ngama M, Karisa J, Babu L, Muturi M, Mwatasa M, Adetifa J, Kern C, Duthaler U, Hammann F, Rabinovich R, Chaccour C, and Maia MF
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- Humans, Female, Adult, Male, Animals, Young Adult, Mosquito Vectors drug effects, Mosquito Control methods, Kenya, Insecticides pharmacokinetics, Insecticides administration & dosage, Drug Administration Schedule, Ivermectin pharmacokinetics, Ivermectin administration & dosage, Albendazole pharmacokinetics, Albendazole administration & dosage, Anopheles drug effects, Malaria prevention & control, Malaria drug therapy
- Abstract
Objectives: When malaria vectors consume ivermectin in a blood meal, their survival probability decreases, potentially reducing malaria transmission during mass drug administrations. However, questions remain regarding the optimal dosing. This study aimed to compare the mosquitocidal effect and pharmacokinetics of two-dose regimens of ivermectin for malaria vector control., Design: We conducted an open-label randomized control trial in Kenya, staggered in blocks with sequential intervention groups and parallel controls. Participants were randomly assigned (2:1:1:1) using computer random-sequence generation, unstratified, with one block of six pharmacokinetics-only participants (single-dose ivermectin) and six blocks of four participants (3:1 intervention vs control), to receive single-dose ivermectin (400 mcg/kg, n = 12), three daily doses (3-day regimen 300 mcg/kg, n = 6), albendazole (400 mg, n = 6), or no treatment (negative control, n = 6). Our primary outcome was Anopheles gambiae survival (time-to-event [days]) after blood feeding up to 10 days after drug administration. We also evaluated pharmacokinetics (peak plasma and capillary blood concentration, areas under the plasma and capillary blood concentration-time curve from time of last administration to time of last observation, time to reach peak plasma and capillary blood concentration, terminal elimination half-life) up to 7 days after treatment., Results: A total of 36 healthy volunteers aged 21-32 years were recruited into the study and followed up to completion, with two participants not attending the visit on day 28. All drug regimens were well-tolerated. Both regimens showed significant mosquitocidal effect in the first 7 days. At 10 days after treatment, the single dose presented superior longevity of effect (adjusted hazard ratio = 3.91; 95% confidence interval = 1.93-7.93; P <0.001) compared with the triple dose (adjusted hazard ratio = 1.79; 95% confidence interval = 0.88-3.62; P = 0.0.11). Albendazole had, overall, no mosquitocidal effect., Conclusions: It is unclear why a single dose led to increased bio-efficacy compared with a triple dose. We recommend trials investigating ivermectin mass drug administrations for malaria control to consider single-dose ivermectin. A single-dose regimen is also expected to present additional operational advantages compared with a 3-day regimen, leading to improved programmatic suitability., Competing Interests: Declarations of competing interest The authors have no competing interests to declare., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)
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- 2024
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6. Implementation research: a protocol for two three-arm pragmatic randomised controlled trials on continuous glucose monitoring devices in people with type 1 diabetes in South Africa and Kenya.
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Marbán-Castro E, Muhwava L, Kamau Y, Safary E, Rheeder P, Karsas M, Kemp T, Freitas J, Carrihill M, Dave J, Katambo D, Kimetto J, Allie R, Ndungu J, Sigwebela N, Akach D, Girdwood S, Erkosar B, Nichols BE, Haldane C, Vetter B, and Shilton S
- Subjects
- Humans, Blood Glucose analysis, Continuous Glucose Monitoring instrumentation, Cost-Benefit Analysis, Glycemic Control instrumentation, Hypoglycemic Agents therapeutic use, Implementation Science, Insulin therapeutic use, Kenya, Multicenter Studies as Topic, Pragmatic Clinical Trials as Topic, Quality of Life, South Africa, Treatment Outcome, Diabetes Mellitus, Type 1 diagnosis, Diabetes Mellitus, Type 1 drug therapy, Glycated Hemoglobin analysis
- Abstract
Background: Self-monitoring of glucose is an essential component of type 1 diabetes (T1D) management. In recent years, continuous glucose monitoring (CGM) has provided an alternative to daily fingerstick testing for the optimisation of insulin dosing and general glucose management in people with T1D. While studies have been conducted to evaluate the impact of CGM on clinical outcomes in the US, Europe and Australia, there are limited data available for low- and middle-income countries (LMICs) and further empirical evidence is needed to inform policy decision around their use in these countries., Methods: This trial was designed as a pragmatic, parallel-group, open-label, multicentre, three-arm, randomised (1:1:1) controlled trial of continuous or periodic CGM device use versus standard of care in people with T1D in South Africa and Kenya. The primary objective of this trial will be to assess the impact of continuous or periodic CGM device use on glycaemic control as measured by change from baseline glycosylated haemoglobin (HbA1c). Additional assessments will include clinical outcomes (glucose variation, time in/below/above range), safety (adverse events, hospitalisations), quality of life (EQ-5D, T1D distress score, Glucose Monitoring Satisfaction Survey for T1D), and health economic measures (incremental cost-effectiveness ratios, quality adjusted life years)., Discussion: This trial aims to address the substantial evidence gap on the impact of CGM device use on clinical outcomes in LMICs, specifically South Africa and Kenya. The trial results will provide evidence to inform policy and treatment decisions in these countries., Trial Registration: NCT05944731 (Kenya), July 6, 2023; NCT05944718 (South Africa), July 13, 2023., (© 2024. The Author(s).)
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- 2024
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7. A field bioassay for assessing ivermectin bio-efficacy in wild malaria vectors.
- Author
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Ominde KM, Kamau Y, Karisa J, Muturi MN, Kiuru C, Wanjiku C, Babu L, Yaah F, Tuwei M, Musani H, Ondieki Z, Muriu S, Mwangangi J, Chaccour C, and Maia MF
- Subjects
- Animals, Humans, Ivermectin pharmacology, Mosquito Vectors, Glucose pharmacology, Mosquito Control, Anopheles, Insecticides pharmacology, Malaria
- Abstract
Background: Ivermectin (IVM) mass drug administration is a candidate complementary malaria vector control tool. Ingestion of blood from IVM treated hosts results in reduced survival in mosquitoes. Estimating bio-efficacy of IVM on wild-caught mosquitoes requires they ingest the drug in a blood meal either through a membrane or direct feeding on a treated host. The latter, has ethical implications, and the former results in low feeding rates. Therefore, there is a need to develop a safe and effective method for IVM bio-efficacy monitoring in wild mosquitoes., Methods: Insectary-reared Anopheles gambiae s.s. were exposed to four IVM doses: 85, 64, 43, 21 ng/ml, and control group (0 ng/ml) in three different solutions: (i) blood, (ii) 10% glucose, (iii) four ratios (1:1, 1:2, 1:4, 1:8) of blood in 10% glucose, and fed through filter paper. Wild-caught An. gambiae s.l. were exposed to 85, 43 and 21 ng/ml IVM in blood and 1:4 ratio of blood-10% glucose mixture. Survival was monitored for 28 days and a pool of mosquitoes from each cohort sacrificed immediately after feeding and weighed to determine mean weight of each meal type., Results: When administered in glucose solution, mosquitocidal effect of IVM was not comparable to the observed effects when similar concentrations were administered in blood. Equal concentrations of IVM administered in blood resulted in pronounced reductions in mosquito survival compared to glucose solution only. However, by adding small amounts of blood to glucose solution, mosquito mortality rates increased resulting in similar effects to what was observed during blood feeding., Conclusion: Bio-efficacy of ivermectin is strongly dependent on mode of drug delivery to the mosquito and likely influenced by digestive processes. The assay developed in this study is a good candidate for field-based bio-efficacy monitoring: wild mosquitoes readily feed on the solution, the assay can be standardized using pre-selected concentrations and by not involving treated blood hosts (human or animal) variation in individual pharmacokinetic profiles as well as ethical issues are bypassed. Meal volumes did not explain the difference in the lethality of IVM across the different meal types necessitating further research on the underlying mechanisms., (© 2023. BioMed Central Ltd., part of Springer Nature.)
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- 2023
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8. Implementing at-birth, point-of-care HIV testing in Kenya: a qualitative study using the Consolidated Framework for Implementation Research.
- Author
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Wexler C, Kamau Y, Muchoki E, Babu S, Maosa N, Maloba M, Brown M, Goggin K, Mabachi N, Gautney B, and Finocchario-Kessler S
- Abstract
Background: At-birth and point-of-care (POC) testing can expedite early infant diagnosis of HIV and improve infant outcomes. Guided by the Consolidated Framework for Implementation Research (CFIR), this study describes the implementation of an at-birth POC testing pilot from the perspective of implementing providers and identifies the factors that might support and hinder the scale up of these promising interventions., Methods: We conducted 28 focus group discussions (FGDs) with 48 providers across 4 study sites throughout the course of a pilot study assessing the feasibility and impact of at-birth POC testing. FGDs were audio-recorded, transcribed, and analyzed for a priori themes related to CFIR constructs. This qualitative study was nested within a larger study to pilot and evaluate at-birth and POC HIV testing., Results: Out of the 39 CFIR constructs, 30 were addressed in the FGDs. While all five domains were represented, major themes revolved around constructs related to intervention characteristics, inner setting, and outer setting. Regarding intervention characteristics, the advantages of at-birth POC (rapid turnaround time resulting in improved patient management and enhanced patient motivation) were significant enough to encourage provider uptake and enthusiasm. Challenges at the intervention level (machine breakdown, processing errors), inner settings (workload, limited leadership engagement, challenges with access to information), and outer setting (patient-level challenges, limited engagement with outer setting stakeholders) hindered implementation, frustrated providers, and resulted in missed opportunities for testing. Providers discussed how throughout the course of the study adaptations to implementation (improved channels of communication, modified implementation logistics) were made to overcome some of these challenges. To improve implementation, providers cited the need for enhanced training and for greater involvement among stakeholders outside of the implementing team (i.e., other clinicians, hospital administrators and implementing partners, county and national health officials). Despite provider enthusiasm for the intervention, providers felt that the lack of engagement from leadership within the hospital and in the outer setting would preclude sustained implementation outside of a research setting., Conclusion: Despite demonstrated feasibility and enthusiasm among implementing providers, the lack of outer setting support makes sustained implementation of at-birth POC testing unlikely at this time. The findings highlight the multi-dimensional aspect of implementation and the need to consider facilitators and barriers within each of the five CFIR domains., Trial Registration: ClinicalTrials.gov, NCT03435887 . Retrospectively registered on 19 February 2020., (© 2021. The Author(s).)
- Published
- 2021
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9. Piloting the Feasibility and Preliminary Impact of Adding Birth HIV Polymerase Chain Reaction Testing to the Early Infant Diagnosis Guidelines in Kenya.
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Finocchario-Kessler S, Wexler C, Brown M, Goggin K, Lwembe R, Nazir N, Gautney B, Khamadi S, Babu S, Muchoki E, Maosa N, Mabachi N, Kamau Y, and Maloba M
- Subjects
- Adult, Early Diagnosis, Feasibility Studies, Female, HIV Infections prevention & control, HIV Infections transmission, Humans, Infant, Infant, Newborn, Infectious Disease Transmission, Vertical prevention & control, Kenya epidemiology, Pilot Projects, Point-of-Care Systems, Polymerase Chain Reaction, Pregnancy, HIV Infections diagnosis, HIV Testing methods, Infant, Newborn, Diseases diagnosis
- Abstract
Background: In Kenya, standard early infant diagnosis (EID) with polymerase chain reaction (PCR) testing at 6-week postnatal achieves early treatment initiation (<12 weeks) in <20% of HIV+ infants. Kenya's new early infant diagnosis guidelines tentatively proposed adding PCR testing at birth, pending results from pilot studies., Methods: We piloted birth testing at 4 Kenyan hospitals between November 2017 and November 2018. Eligible HIV-exposed infants were offered both point-of-care and PCR HIV testing at birth (window 0 to <4 weeks) and 6 weeks (window 4-12 weeks). We report the: proportion of infants tested at birth, 6-week, and both birth and 6-week testing; median infant age at results; seropositivity and antiretroviral therapy initiation., Results: Final sample included 624 mother-infant pairs. Mean maternal age was 30.4 years, 73.2% enrolled during antenatal care and 89.9% had hospital deliveries. Among the 590 mother-infants pairs enrolled before 4 weeks postnatal, 452 (76.6%) completed birth testing before 4 weeks, with 360 (79.6%) testing within 2 weeks, and 178 (39.4%) before hospital discharge (0-2 days). Mothers were notified of birth PCR results at a median infant age of 5.4 weeks. Among all 624 enrolled infants, 575 (92.1%) were tested during the 6-week window; 417 (66.8%) received testing at both birth and 6-weeks; and 207 received incomplete testing (93.3% only 1 PCR and 6.7% no PCR). Four infants were diagnosed with HIV, and 3 infants were initiated on antiretroviral therapy early, before 12 weeks of age., Conclusions: Uptake of PCR testing at birth was high and a majority of infants received repeat testing at 6 weeks of age., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2021 The Author(s). Published by Wolters Kluwer Health, Inc.)
- Published
- 2021
- Full Text
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10. Women's preferences, expectations, and experiences with male partner support throughout prevention of mother to child transmission of HIV services: a mixed-methods study.
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Wexler C, Brown M, Maloba M, Goggin K, Mabachi N, Kamau Y, Gautney B, Koech S, Lagat S, and Finocchario-Kessler S
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- Child, Female, Humans, Infectious Disease Transmission, Vertical prevention & control, Kenya, Male, Motivation, Pregnancy, Sexual Partners, Social Support, HIV Infections prevention & control, Pregnancy Complications, Infectious prevention & control
- Abstract
Male involvement in prevention of mother to child transmission of HIV (PMTCT) care improves maternal and child outcomes. We conducted a mixed-methods study at two Kenyan government hospitals. We quantitatively assessed women's expectations and preferences for male partner involvement in PMTCT and male partner attendance at PMTCT appointments. Qualitative interviews with women during the postpartum period assessed types of support women received from their male partners. At enrollment, most participants wanted (75%) and expected (69%) male partners to attend appointments; yet, only 9% had a male partner attend any appointments. Most women agreed that their partner would: support them financially (81%), help follow doctor's guidance (61%), support a hospital-based delivery (85%), and want to receive text messages (68%). Expectations and preferences varied by women's characteristics, most notably experiences with mistreatment, disclosure status, and knowledge of male partner's HIV status. In qualitative interviews, instrumental (financial) support was the most frequently discussed type of support. Male partners also provided informational support by reminding women of medication or appointments. Women reported a variety of ways in which their male partners supported them through PMTCT; however, there was a gap between women's expectation for male partner attendance and the level of male attendance achieved.
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- 2021
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11. "Closing the Gap": Provider Recommendations for Implementing Birth Point of Care HIV Testing.
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Wexler C, Kamau Y, Halder R, Brown M, Maloba M, Mabachi N, Sandbulte M, Gautney B, Goggin K, Odeny T, and Finocchario-Kessler S
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- Adult, Female, HIV Infections drug therapy, HIV Infections prevention & control, Humans, Infant, Newborn, Kenya, Male, Middle Aged, Serologic Tests, Anti-Retroviral Agents administration & dosage, Early Diagnosis, HIV Infections diagnosis, Health Personnel, Mass Screening methods, Point-of-Care Systems organization & administration, Point-of-Care Testing
- Abstract
Delays in traditional HIV DNA PCR testing for early infant diagnosis (EID) at 6 weeks of age result in late antiretroviral treatment (ART). Birth point of care (POC) testing is an emerging strategy with the potential to streamline EID services. We elicited providers' recommendations for introducing birth POC testing to guide strategies in Kenya and similar settings. We conducted formative interviews with 26 EID providers from four Kenyan hospitals prior to POC implementation. Providers discussed the need for comprehensive training, covering both EID and POC-specific topics for all key personnel. Providers highlighted equipment considerations, such as protocols for maintenance and safe storage. Providers emphasized the need for maternal counseling to ensure patient acceptance and most agreed that specimen collection for birth POC testing should occur in the maternity department and supported a multidisciplinary approach. Though most providers supported ART initiation based on a positive birth POC result, a few expressed concerns with result validity. To maximize implementation success, provider training, equipment security, maternal counseling, and logistics of testing must be planned and communicated to providers.
- Published
- 2019
- Full Text
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