Last data update: Apr 22, 2024. (Total: 46599 publications since 2009)
Records 1-5 (of 5 Records) |
Query Trace: Zahoor N [original query] |
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Polyvalent immunization elicits a synergistic broadly neutralizing immune response to hypervariable region 1 variants of hepatitis C virus
Mosa AI , Campo DS , Khudyakov Y , AbouHaidar MG , Gehring AJ , Zahoor A , Ball JK , Urbanowicz RA , Feld JJ . Proc Natl Acad Sci U S A 2023 120 (24) e2220294120 A hepatitis C virus (HCV) vaccine is urgently needed. Vaccine development has been hindered by HCV's genetic diversity, particularly within the immunodominant hypervariable region 1 (HVR1). Here, we developed a strategy to elicit broadly neutralizing antibodies to HVR1, which had previously been considered infeasible. We first applied a unique information theory-based measure of genetic distance to evaluate phenotypic relatedness between HVR1 variants. These distances were used to model the structure of HVR1's sequence space, which was found to have five major clusters. Variants from each cluster were used to immunize mice individually, and as a pentavalent mixture. Sera obtained following immunization neutralized every variant in a diverse HCVpp panel (n = 10), including those resistant to monovalent immunization, and at higher mean titers (1/ID(50) = 435) than a glycoprotein E2 (1/ID(50) = 205) vaccine. This synergistic immune response offers a unique approach to overcoming antigenic variability and may be applicable to other highly mutable viruses. |
A fully automated high-throughput liquid chromatography tandem mass spectrometry method for measuring creatinine in urine
Zahoor N , Danilenko U , Vesper HW . Clin Mass Spectrom 2019 11 1-7 Reliable creatinine measurements are important to evaluate kidney function and for creatinine correction to reduce biological variability of other urinary analytes. A high-throughput, accurate liquid chromatography tandem mass spectrometry method for quantitation of human urinary creatinine has been developed and validated. Sample preparation was fully automated including cryovial decapping, sample ID scanning and two serial dilution steps. Quantitation was performed using a stable isotope-labeled internal standard. Multiplexed chromatographic separation of creatinine was achieved within a one-minute analysis and followed by tandem mass spectrometry in positive electrospray ionization mode. The precursor and product ions of creatinine and D3-creatinine were monitored in selected reaction monitoring mode. Method validation results showed reproducibility with within-run precision of 3.59, 3.49 and 2.84% and between-run precision of 4.01, 3.28 and 3.57% for low, medium and high quality control materials prepared from pooled donor urine, respectively. The method showed excellent accuracy with a bias of −1.94%, −0.78% and −1.07% for three levels of certified reference material. The calibration curve was linear throughout a 7.50–300 mg/dL (0.663–26.5 mmol/L) measurement range (R2 = 0.999), with the mean slope of 0.0115 (95%CI, 0.0108–0.0122) and intercept of 0.0027 (95%CI, 0.0003–0.0051). The limit of detection (LOD) of the method was 3.17 mg/dL (0.280 mmol/L). Analytical specificity was achieved by chromatographically separating creatinine from potentially interfering creatine within a one-minute run and monitoring the Quantitation Ion/Confirmation Ion (QI/CI) ratios in samples. A simple, accurate, high-throughput method was successfully developed for measuring creatinine in human urine samples. |
The role of supplementary environmental surveillance to complement acute flaccid paralysis surveillance for wild poliovirus in Pakistan - 2011-2013.
Cowger TL , Burns CC , Sharif S , Gary HE Jr , Iber J , Henderson E , Malik F , Zahoor Zaidi SS , Shaukat S , Rehman L , Pallansch MA , Orenstein WA . PLoS One 2017 12 (7) e0180608 BACKGROUND: More than 99% of poliovirus infections are non-paralytic and therefore, not detected by acute flaccid paralysis (AFP) surveillance. Environmental surveillance (ES) can detect circulating polioviruses from sewage without relying on clinical presentation. With extensive ES and continued circulation of polioviruses, Pakistan presents a unique opportunity to quantify the impact of ES as a supplement to AFP surveillance on overall completeness and timeliness of poliovirus detection. METHODS: Genetic, geographic and temporal data were obtained for all wild poliovirus (WPV) isolates detected in Pakistan from January 2011 through December 2013. We used viral genetics to assess gaps in AFP surveillance and ES as measured by detection of 'orphan viruses' (≥1.5% different in VP1 capsid nucleotide sequence). We compared preceding detection of closely related circulating isolates (≥99% identity) detected by AFP surveillance or ES to determine which surveillance system first detected circulation before the presentation of each polio case. FINDINGS: A total of 1,127 WPV isolates were detected by AFP surveillance and ES in Pakistan from 2011-2013. AFP surveillance and ES combined exhibited fewer gaps (i.e., % orphan viruses) in detection than AFP surveillance alone (3.3% vs. 7.7%, respectively). ES detected circulation before AFP surveillance in nearly 60% of polio cases (200 of 346). For polio cases reported from provinces conducting ES, ES detected circulation nearly four months sooner on average (117.6 days) than did AFP surveillance. INTERPRETATION: Our findings suggest ES in Pakistan is providing earlier, more sensitive detection of wild polioviruses than AFP surveillance alone. Overall, targeted ES through strategic selection of sites has important implications in the eradication endgame strategy. |
Polio eradication initiative in Afghanistan, 1997-2013
Simpson DM , Sadr-Azodi N , Mashal T , Sabawoon W , Pardis A , Quddus A , Garrigos C , Guirguis S , Zahoor Zaidi SS , Shaukat S , Sharif S , Asghar H , Hadler SC . J Infect Dis 2014 210 Suppl 1 S162-72 BACKGROUND: This article reviews the epidemiology of polio, acute flaccid paralysis (AFP) surveillance, and the implementation of supplemental immunization activities (SIAs) in Afghanistan from 1997 thru 2013. METHODS: Published reports and unpublished national data on polio cases, AFP surveillance, and SIAs were analyzed. Recommendations from independent advisory groups and Afghan government informed the conclusions. RESULTS: From 1997 thru 2013, the annual number of confirmed polio cases fluctuated from a low of 4 in 2004 to a high of 80 in 2011. Wild poliovirus types 2 and 3 were last reported in 1997 and 2010, respectively. Circulating vaccine-derived poliovirus type 2 emerged in 2009. AFP surveillance quality in children aged <15 years improved over time, achieving rates >8 per 100 000 population. Since 2001, at least 6 SIAs have been conducted annually. CONCLUSIONS: Afghanistan has made progress moving closer to eliminating polio. The program struggles to reach all children because of management and accountability problems in the field, inaccessible populations, and inadequate social mobilization. Consequently, too many children are missed during SIAs. Afghanistan adopted a national emergency action plan in 2012 to address these issues, but national elimination will require consistent and complete implementation of proven strategies. |
Molecular epidemiology of influenza A(H1N1)pdm09 viruses from Pakistan in 2009-2010.
Bashir Aamir U , Badar N , Mehmood MR , Nisar N , Suleman RM , Shaukat S , Sharif S , Kamran J , Zaidi SS , Kazi BM , Gubareva L , Xu X , Garten R , Klimov A . PLoS One 2012 7 (8) e41866 BACKGROUND: In early 2009, a novel influenza A(H1N1) virus that emerged in Mexico and United States rapidly disseminated worldwide. The spread of this virus caused considerable morbidity with over 18,000 recorded deaths. The new virus was found to be a reassortant containing gene segments from human, avian and swine influenza viruses. METHODS/RESULTS: The first case of human infection with A(H1N1)pdm09 in Pakistan was detected on 18(th) June 2009. Since then, 262 laboratory-confirmed cases have been detected during various outbreaks with 29 deaths (as of 31(st) August 2010). The peak of the epidemic was observed in December with over 51% of total respiratory cases positive for influenza. Representative isolates from Pakistan viruses were sequenced and analyzed antigenically. Sequence analysis of genes coding for surface glycoproteins HA and NA showed high degree of high levels of sequence identity with corresponding genes of regional viruses circulating South East Asia. All tested viruses were sensitive to Oseltamivir in the Neuraminidase Inhibition assays. CONCLUSIONS: Influenza A(H1N1)pdm09 viruses from Pakistan form a homogenous group of viruses. Their HA genes belong to clade 7 and show antigenic profile similar to the vaccine strain A/California/07/2009. These isolates do not show any amino acid changes indicative of high pathogenicity and virulence. It is imperative to continue monitoring of these viruses for identification of potential variants of high virulence or drug resistance. |
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