Last data update: Dec 02, 2024. (Total: 48272 publications since 2009)
Records 1-10 (of 10 Records) |
Query Trace: Smith LA[original query] |
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Update: Interim guidance for health care providers caring for pregnant women with possible Zika virus exposure - United States (including U.S. territories), July 2017
Oduyebo T , Polen KD , Walke HT , Reagan-Steiner S , Lathrop E , Rabe IB , Kuhnert-Tallman WL , Martin SW , Walker AT , Gregory CJ , Ades EW , Carroll DS , Rivera M , Perez-Padilla J , Gould C , Nemhauser JB , Ben Beard C , Harcourt JL , Viens L , Johansson M , Ellington SR , Petersen E , Smith LA , Reichard J , Munoz-Jordan J , Beach MJ , Rose DA , Barzilay E , Noonan-Smith M , Jamieson DJ , Zaki SR , Petersen LR , Honein MA , Meaney-Delman D . MMWR Morb Mortal Wkly Rep 2017 66 (29) 781-793 CDC has updated the interim guidance for U.S. health care providers caring for pregnant women with possible Zika virus exposure in response to 1) declining prevalence of Zika virus disease in the World Health Organization's Region of the Americas (Americas) and 2) emerging evidence indicating prolonged detection of Zika virus immunoglobulin M (IgM) antibodies. Zika virus cases were first reported in the Americas during 2015-2016; however, the incidence of Zika virus disease has since declined. As the prevalence of Zika virus disease declines, the likelihood of false-positive test results increases. In addition, emerging epidemiologic and laboratory data indicate that, as is the case with other flaviviruses, Zika virus IgM antibodies can persist beyond 12 weeks after infection. Therefore, IgM test results cannot always reliably distinguish between an infection that occurred during the current pregnancy and one that occurred before the current pregnancy, particularly for women with possible Zika virus exposure before the current pregnancy. These limitations should be considered when counseling pregnant women about the risks and benefits of testing for Zika virus infection during pregnancy. This updated guidance emphasizes a shared decision-making model for testing and screening pregnant women, one in which patients and providers work together to make decisions about testing and care plans based on patient preferences and values, clinical judgment, and a balanced assessment of risks and expected outcomes. |
Characterization of Hemagglutinin Negative Botulinum Progenitor Toxins.
Kalb SR , Baudys J , Smith TJ , Smith LA , Barr JR . Toxins (Basel) 2017 9 (6) Botulism is a disease involving intoxication with botulinum neurotoxins (BoNTs), toxic proteins produced by Clostridium botulinum and other clostridia. The 150 kDa neurotoxin is produced in conjunction with other proteins to form the botulinum progenitor toxin complex (PTC), alternating in size from 300 kDa to 500 kDa. These progenitor complexes can be classified into hemagglutinin positive or hemagglutinin negative, depending on the ability of some of the neurotoxin-associated proteins (NAPs) to cause hemagglutination. The hemagglutinin positive progenitor toxin complex consists of BoNT, nontoxic non-hemagglutinin (NTNH), and three hemagglutinin proteins; HA-70, HA-33, and HA-17. Hemagglutinin negative progenitor toxin complexes contain BoNT and NTNH as the minimally functional PTC (M-PTC), but not the three hemagglutinin proteins. Interestingly, the genome of hemagglutinin negative progenitor toxin complexes comprises open reading frames (orfs) which encode for three proteins, but the existence of these proteins has not yet been extensively demonstrated. In this work, we demonstrate that these three proteins exist and form part of the PTC for hemagglutinin negative complexes. Several hemagglutinin negative strains producing BoNT/A, /E, and /F were found to contain the three open reading frame proteins. Additionally, several BoNT/A-containing bivalent strains were examined, and NAPs from both genes, including the open reading frame proteins, were associated with BoNT/A. The open reading frame encoded proteins are more easily removed from the botulinum complex than the hemagglutinin proteins, but are present in several BoNT/A and /F toxin preparations. These are not easily removed from the BoNT/E complex, however, and are present even in commercially-available purified BoNT/E complex. |
Lessons of risk communication and health promotion - West Africa and United States
Bedrosian SR , Young CE , Smith LA , Cox JD , Manning C , Pechta L , Telfer JL , Gaines-McCollom M , Harben K , Holmes W , Lubell KM , McQuiston JH , Nordlund K , O'Connor J , Reynolds BS , Schindelar JA , Shelley G , Daniel KL . MMWR Suppl 2016 65 (3) 68-74 During the response to the 2014-2016 Ebola virus disease (Ebola) epidemic in West Africa, CDC addressed the disease on two fronts: in the epidemic epicenter of West Africa and at home in the United States. Different needs drove the demand for information in these two regions. The severity of the epidemic was reflected not only in lives lost but also in the amount of fear, misinformation, and stigma that it generated worldwide. CDC helped increase awareness, promoted actions to stop the spread of Ebola, and coordinated CDC communication efforts with multiple international and domestic partners. CDC, with input from partners, vastly increased the number of Ebola communication materials for groups with different needs, levels of health literacy, and cultural preferences. CDC deployed health communicators to West Africa to support ministries of health in developing and disseminating clear, science-based messages and promoting science-based behavioral interventions. Partnerships in West Africa with local radio, television, and cell phone businesses made possible the dissemination of messages appropriate for maximum effect. CDC and its partners communicated evolving science and risk in a culturally appropriate way to motivate persons to adapt their behavior and prevent infection with and spread of Ebola virus. Acknowledging what is and is not known is key to effective risk communication, and CDC worked with partners to integrate health promotion and behavioral and cultural knowledge into the response to increase awareness of the actual risk for Ebola and to promote protective actions and specific steps to stop its spread. The activities summarized in this report would not have been possible without collaboration with many U.S. and international partners (http://www.cdc.gov/vhf/ebola/outbreaks/2014-west-africa/partners.html). |
Three enzymatically active neurotoxins of Clostridium botulinum strain Af84: BoNT/A2, /F4, and /F5
Kalb SR , Baudys J , Smith TJ , Smith LA , Barr JR . Anal Chem 2014 86 (7) 3254-62 Botulinum neurotoxins (BoNTs) are produced by various species of clostridia and are potent neurotoxins which cause the disease botulism, by cleaving proteins needed for successful nerve transmission. There are currently seven confirmed serotypes of BoNTs, labeled A-G, and toxin-producing clostridia typically only produce one serotype of BoNT. There are a few strains (bivalent strains) which are known to produce more than one serotype of BoNT, producing either both BoNT/A and /B, BoNT/A and /F, or BoNT/B and /F, designated as Ab, Ba, Af, or Bf. Recently, it was reported that Clostridium botulinum strain Af84 has three neurotoxin gene clusters: bont/A2, bont/F4, and bont/F5. This was the first report of a clostridial organism containing more than two neurotoxin gene clusters. Using a mass spectrometry based proteomics approach, we report here that all three neurotoxins, BoNT/A2, /F4, and /F5, are produced by C. botulinum Af84. Label free MS(E) quantification of the three toxins indicated that toxin composition is 88% BoNT/A2, 1% BoNT/F4, and 11% BoNT/F5. The enzymatic activity of all three neurotoxins was assessed by examining the enzymatic activity of the neurotoxins upon peptide substrates, which mimic the toxins' natural targets, and monitoring cleavage of the substrates by mass spectrometry. We determined that all three neurotoxins are enzymatically active. This is the first report of three enzymatically active neurotoxins produced in a single strain of Clostridium botulinum. |
De novo subtype and strain identification of botulinum neurotoxin type B through toxin proteomics
Kalb SR , Baudys J , Rees JC , Smith TJ , Smith LA , Helma CH , Hill K , Kull S , Kirchner S , Dorner MB , Dorner BG , Pirkle JL , Barr JR . Anal Bioanal Chem 2012 403 (1) 215-26 Botulinum neurotoxins (BoNTs) cause the disease botulism, which can be lethal if untreated. There are seven known serotypes of BoNT, A-G, defined by their response to antisera. Many serotypes are distinguished into differing subtypes based on amino acid sequence, and many subtypes are further differentiated into toxin variants. Previous work in our laboratory described the use of a proteomics approach to distinguish subtype BoNT/A1 from BoNT/A2 where BoNT identities were confirmed after searching data against a database containing protein sequences of all known BoNT/A subtypes. We now describe here a similar approach to differentiate subtypes BoNT/B1, /B2, /B3, /B4, and /B5. Additionally, to identify new subtypes or hitherto unpublished amino acid substitutions, we created an amino acid substitution database covering every possible amino acid change. We used this database to differentiate multiple toxin variants within subtypes of BoNT/B1 and B2. More importantly, with our amino acid substitution database, we were able to identify a novel BoNT/B subtype, designated here as BoNT/B7. These techniques allow for subtype and strain level identification of both known and unknown BoNT/B rapidly with no DNA required. |
Discovery of a novel enzymatic cleavage site for botulinum neurotoxin F5.
Kalb SR , Baudys J , Webb RP , Wright P , Smith TJ , Smith LA , Fernandez R , Raphael BH , Maslanka SE , Pirkle JL , Barr JR . FEBS Lett 2011 586 (2) 109-15 Botulinum neurotoxins (BoNTs) cause botulism by cleaving proteins necessary for nerve transmission. There are seven serotypes of BoNT, A-G, characterized by their response to antisera. Many serotypes are further distinguished into differing subtypes based on amino acid sequence some of which result in functional differences. Our laboratory previously reported that all tested subtypes within each serotype have the same site of enzymatic activity. Recently, three new subtypes of BoNT/F; /F3, /F4, and /F5, were reported. Here, we report that BoNT/F5 cleaves substrate synaptobrevin-2 in a different location than the other BoNT/F subtypes, between (54)L and (55)E. This is the first report of cleavage of synaptobrevin-2 in this location. STRUCTURED SUMMARY OF PROTEIN INTERACTIONS: BoNT/F5cleavesSynaptobrevin-2 by protease assay (View interaction: 1, 2) BoNT/F1cleavesSynaptobrevin-2 by protease assay (View interaction: 1, 2). |
Extraction and inhibition of enzymatic activity of Botulinum neurotoxins/B1, /B2, /B3, /B4, and /B5 by a panel of monoclonal anti-BoNT/B antibodies
Kalb SR , Santana WI , Geren IN , Garcia-Rodriguez C , Lou J , Smith TJ , Marks JD , Smith LA , Pirkle JL , Barr JR . BMC Biochem 2011 12 (1) 58 BACKGROUND: Botulism is caused by botulinum neurotoxins (BoNTs), extremely toxic proteins which can induce respiratory failure leading to long-term intensive care or death. Treatment for botulism includes administration of antitoxins, which must be administered early in the course of the intoxication; therefore, rapid determination of human exposure to BoNT is an important public health goal. In previous work, our laboratory reported on Endopep-MS, a mass spectrometry-based activity method for detecting and differentiating BoNT/A, /B, /E, and /F in clinical samples. We also demonstrated that antibody-capture is effective for purification and concentration of BoNTs from complex matrices such as clinical samples. However, some antibodies inhibit or neutralize the enzymatic activity of BoNT, so the choice of antibody for toxin extraction is critical. RESULTS: In this work, we evaluated 24 anti-BoNT/B monoclonal antibodies (mAbs) for their ability to inhibit the in vitro activity of BoNT/B1, /B2, /B3, /B4, and /B5 and to extract those toxins. Among the mAbs, there were significant differences in ability to extract BoNT/B subtypes and inhibitory effect on BoNT catalytic activity. Some of the mAbs tested enhanced the in vitro light chain activity of BoNT/B, suggesting that BoNT/B may undergo conformational change upon binding some mAbs. CONCLUSIONS: In addition to determining in vitro inhibition abilities of a panel of mAbs against BoNT/B1-/B5, this work has determined B12.2 and 2B18.2 to be the best mAbs for sample preparation prior to Endopep-MS. These mAb characterizations also have the potential to assist with mechanistic studies of BoNT/B protection and treatment, which is important for studying alternative therapeutics for botulism. |
Early diagnoses of autism spectrum disorders in Massachusetts birth cohorts, 2001-2005
Manning SE , Davin CA , Barfield WD , Kotelchuck M , Clements K , Diop H , Osbahr T , Smith LA . Pediatrics 2011 127 (6) 1043-51 OBJECTIVE: We examined trends in autism spectrum disorder diagnoses by age 36 months (early diagnoses) and identified characteristics associated with early diagnoses. METHODS: Massachusetts birth certificate and early-intervention program data were linked to identify infants born between 2001 and 2005 who were enrolled in early intervention and receiving autism-related services before age 36 months (through December 31, 2008). Trends in early autism spectrum disorders were examined using Cochran-Armitage trend tests. chi(2) Statistics were used to compare distributions of selected characteristics for children with and without autism spectrum disorders. Multivariate logistic regression analyses were conducted to identify independent predictors of early diagnoses. RESULTS: A total of 3013 children (77.5 per 10 000 study population births) were enrolled in early intervention for autism spectrum disorder by age 36 months. Autism spectrum disorder incidence increased from 56 per 10 000 infants among the 2001 birth cohort to 93 per 10 000 infants in 2005. Infants of mothers younger than 24 years of age, whose primary language was not English or who were foreign-born had lower odds of an early autism spectrum disorder diagnosis. Maternal age older than 30 years was associated with increased odds of an early autism spectrum disorder diagnosis. Odds of early autism spectrum disorders were 4.5 (95% confidence interval: 4.1-5.0) times higher for boys than girls. CONCLUSIONS: Early autism spectrum disorder diagnoses are increasing in Massachusetts, reflecting the national trend observed among older children. Linkage of early-intervention program data with population-based vital statistics is valuable for monitoring autism spectrum disorder trends and planning developmental and educational service needs. |
Different substrate recognition requirements for cleavage of synaptobrevin-2 by Clostridium baratii and Clostridium botulinum type F neurotoxins
Kalb SR , Baudys J , Egan C , Smith TJ , Smith LA , Pirkle JL , Barr JR . Appl Environ Microbiol 2010 77 (4) 1301-8 Botulinum neurotoxins (BoNTs) cause botulism, which can be fatal if untreated. BoNTs cleave proteins necessary for nerve transmission, resulting in paralysis. The in vivo protein target has been reported for all seven serotypes of BoNT, A-G. Knowledge of the cleavage sites has led to the development of several assays to detect BoNT based on its ability to cleave a peptide substrate derived from its in vivo protein target. Most serotypes of BoNT can be further subdivided into subtypes, and previously, we demonstrated that three of the currently known subtypes of BoNT/F cleave a peptide substrate, a shortened version of synaptobrevin-2, between Q58 and K59. However, our research indicated that Clostridium baratii type F toxin did not cleave this peptide. In this study, we detail experiments demonstrating that Clostridium baratii type F toxin cleaves recombinant synaptobrevin-2 in the same location as proteolytic F toxin. In addition, we demonstrate that Clostridium baratii type F toxin can cleave a peptide substrate based on the sequence of synaptobrevin-2. This peptide substrate is an N-terminal extension of the original peptide substrate used for detection of other BoNT/F toxins and can be used to detect four of the currently known BoNT/F subtypes by mass spectrometry. |
Extraction of BoNT/A, /B, /E, and /F with a single, high affinity monoclonal antibody for detection of botulinum neurotoxin by Endopep-MS
Kalb SR , Garcia-Rodriguez C , Lou J , Baudys J , Smith TJ , Marks JD , Smith LA , Pirkle JL , Barr JR . PLoS One 2010 5 (8) e12237 Botulinum neurotoxins (BoNTs) are extremely potent toxins that are capable of causing respiratory failure leading to long-term intensive care or death. The best treatment for botulism includes serotype-specific antitoxins, which are most effective when administered early in the course of the intoxication. Early confirmation of human exposure to any serotype of BoNT is an important public health goal. In previous work, we focused on developing Endopep-MS, a mass spectrometry-based endopeptidase method for detecting and differentiating the seven serotypes (BoNT/A-G) in buffer and BoNT/A, /B, /E, and /F (the four serotypes that commonly affect humans) in clinical samples. We have previously reported the success of antibody-capture to purify and concentrate BoNTs from complex matrices, such as clinical samples. However, to check for any one of the four serotypes of BoNT/A, /B, /E, or /F, each sample is split into 4 aliquots, and tested for the specific serotypes separately. The discovery of a unique monoclonal antibody that recognizes all four serotypes of BoNT/A, /B, /E and /F allows us to perform simultaneous detection of all of them. When applied in conjunction with the Endopep-MS assay, the detection limit for each serotype of BoNT with this multi-specific monoclonal antibody is similar to that obtained when using other serotype-specific antibodies. |
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