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Winton AJ, Allen MA. Rational Design of a Bifunctional Peptide Exhibiting Lithium Titanate Oxide and Carbon Nanotube Affinities for Lithium-Ion Battery Applications. ACS Appl Mater Interfaces 2023; 15:8579-8589. [PMID: 36729082 DOI: 10.1021/acsami.2c18018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Phage display is employed as a method for identifying polypeptides that bind to lithium-ion battery materials, specifically lithium titanate oxide (LTO) and multiwalled carbon nanotubes (MWCNTs). Output/input assays are used as a quantitative measure to narrow down the strongest binding polypeptides from several peptides selected through biopanning. Negatively stained transmission electron microscopy is used to verify that a phage presenting a particular LTO or MWCNT binding peptide sequence colocalizes with the respective material. Heterologous expression allows for ample polypeptides to be grown and purified using a peptide expression vector. Isothermal titration calorimetry in conjunction with alanine scanning enables determination of the pertinent residues involved in LTO binding and yields a dissociation constant of 3.41 μM. A rationally designed bifunctional peptide exhibiting LTO and MWCNT binding domains is subsequently validated to exhibit both LTO and MWCNT affinities and is incorporated as a binding agent in LTO coin-type electrochemical cells where the bifunctional peptide demonstrates stability at high cycle rates and potential as an alternative to non-specific binding agents for aqueous slurry processing of lithium-ion battery electrodes.
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Affiliation(s)
- Alexander J Winton
- Department of Chemistry & Biochemistry, University of Maryland Baltimore County, Baltimore, Maryland 21250, United States
| | - Mark A Allen
- Department of Chemistry & Biochemistry, University of Maryland Baltimore County, Baltimore, Maryland 21250, United States
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Asaad M, Van Handel A, Akhavan AA, Huang TCT, Rajesh A, Shen KR, Allen MA, Sharaf B, Moran SL. Prophylactic Bronchial Stump Support With Intrathoracic Muscle Flap Transposition. Ann Plast Surg 2021; 86:317-322. [PMID: 33555686 DOI: 10.1097/sap.0000000000002451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Bronchopleural fistula (BPF) is a dreaded complication of pulmonary resection. For high-risk patients, bronchial stump coverage with vascularized tissue has been recommended. The goal of this study was to report our experience with intrathoracic muscle transposition for bronchial stump coverage. METHODS A retrospective review of all patients who underwent intrathoracic muscle flap transposition as a prophylactic measure at our institution between 1990 and 2010 was conducted. Demographics, surgical characteristics, and complication rates were abstracted and analyzed. RESULTS A total of 160 patients were identified. The most common lung resections performed were pneumonectomy (n = 69, 43%) and lobectomy (n = 60, 38%). A total of 168 flaps were used where serratus anterior was the most common flap (n = 136, 81%), followed by intercostal (n = 14, 8%), and latissimus dorsi (n = 12, 7%). Ten patients (6%) developed BPF, and empyema occurred in 13 patients (8%). Median survival was 20 months, and operative mortality occurred in 7 patients (4%). CONCLUSIONS Reinforcement of the bronchial closure with vascularized muscle is a viable option for potentially decreasing the incidence of BPF in high-risk patients. Further randomized studies are needed to determine the efficacy of this technique for BPF prevention.
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Affiliation(s)
- Malke Asaad
- From the Division of Plastic Surgery, Department of Surgery, Mayo Clinic
| | | | | | - Tony C T Huang
- From the Division of Plastic Surgery, Department of Surgery, Mayo Clinic
| | | | - K Robert Shen
- Division of General Thoracic Surgery, Department of Surgery, Mayo Clinic, Rochester, MN
| | - Mark A Allen
- Division of General Thoracic Surgery, Department of Surgery, Mayo Clinic, Rochester, MN
| | - Basel Sharaf
- From the Division of Plastic Surgery, Department of Surgery, Mayo Clinic
| | - Steven L Moran
- From the Division of Plastic Surgery, Department of Surgery, Mayo Clinic
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Asaad M, Van Handel A, Akhavan AA, Huang TTC, Rajesh A, Allen MA, Shen KR, Sharaf B, Moran SL. Intrathoracic Muscle Flap Transposition for the Management of Chronic Pulmonary Aspergillosis. J Plast Reconstr Aesthet Surg 2020; 73:1815-1824. [PMID: 32593571 DOI: 10.1016/j.bjps.2020.05.068] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 03/04/2020] [Accepted: 05/09/2020] [Indexed: 11/30/2022]
Abstract
BACKGROUND The management of chronic pulmonary aspergillosis remains a challenge for thoracic and reconstructive surgeons. Different management options have been proposed with no consensus regarding the best treatment modality. The goal of this study is to report our experience with the use of intrathoracic muscle flaps for the management of pulmonary aspergillosis. METHODS We retrospectively reviewed all patients who underwent intrathoracic muscle flap transposition for the management of pulmonary aspergillosis between 1990 and 2010. Demographics, surgical characteristics, and treatment outcomes were collected and analyzed. RESULTS A total of 39 patients who underwent 48 muscle flaps were identified. The majority were classified as ASA 3 (n=30, 77%) or ASA 4 (n=8, 21%). Serratus anterior was the most common flap used (n=34), followed by latissimus dorsi (n=6) and pectoralis major (n=5). Flap loss was encountered in three (8%) patients (2 partial, 1 total). Bronchopleural fistula and empyema comprised the two most common intrathoracic complications (26%, 29% respectively). Median follow-up was 33 months (range, 0-216). Successful treatment was achieved in 77% of patients, while operative mortality was 23%. CONCLUSION The use of intrathoracic muscle flaps can be a helpful adjunct to surgical resection in the treatment of chronic pulmonary aspergillosis with low rates of flap loss.
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Affiliation(s)
- Malke Asaad
- Division of Plastic Surgery, Department of Surgery, Mayo Clinic, 200 First Street SW Rochester, MN
| | | | - Arya A Akhavan
- Mayo Clinic Alix School of Medicine, Rochester, Minnesota
| | - Tony T C Huang
- Division of Plastic Surgery, Department of Surgery, Mayo Clinic, 200 First Street SW Rochester, MN
| | - Aashish Rajesh
- Department of Surgery, Mayo Clinic, Rochester, Minnesota
| | - Mark A Allen
- Division of General Thoracic Surgery, Department of Surgery, Mayo Clinic, Rochester, Minnesota
| | - K Robert Shen
- Division of General Thoracic Surgery, Department of Surgery, Mayo Clinic, Rochester, Minnesota
| | - Basel Sharaf
- Division of Plastic Surgery, Department of Surgery, Mayo Clinic, 200 First Street SW Rochester, MN
| | - Steven L Moran
- Division of Plastic Surgery, Department of Surgery, Mayo Clinic, 200 First Street SW Rochester, MN.
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Asaad M, Van Handel A, Akhavan AA, Huang TCT, Rajesh A, Allen MA, Shen KR, Sharaf B, Moran SL. Muscle Flap Transposition for the Management of Intrathoracic Fistulas. Plast Reconstr Surg 2020; 145:829e-838e. [PMID: 32221235 DOI: 10.1097/prs.0000000000006670] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Intrathoracic fistulas pose unique challenges for thoracic and reconstructive surgeons. To decrease the incidence of fistula recurrence, pedicled flaps have been suggested to buttress the repair site. The authors aimed to report their experience with muscle flap transposition for the management of intrathoracic fistulas. METHODS A retrospective review of all patients who underwent intrathoracic muscle flap transposition for the management of intrathoracic fistulas from 1990 to 2010 was conducted. Patient demographics, surgical characteristics, and complication rates were abstracted and analyzed. RESULTS A total of 198 patients were identified. Bronchopleural fistula was present in 156 of the patients (79 percent), and 48 had esophageal fistula (24 percent). A total of 238 flaps were used, constituting an average of 1.2 flaps per patient. After the initial fistula repair, bronchopleural fistula complicated the course of 34 patients (17 percent), and esophageal fistula occurred in 13 patients (7 percent). Partial flap loss was identified in 11 flaps (6 percent), and total flap loss occurred in four flaps (2 percent). Median follow-up was 27 months. At the last follow-up, 182 of the patients (92 percent) had no evidence of fistula, 175 (89 percent) achieved successful chest closure, and 164 (83 percent) had successful treatment. Preoperative radiation therapy and American Society of Anesthesiologists score of 4 or greater were identified as risk factors for unsuccessful treatment. CONCLUSIONS Intrathoracic fistulas remain a source of major morbidity and mortality. Reinforcement of the fistula closure with vascularized muscle flaps is a viable option for preventing dehiscence of the repair site and can be potentially life-saving. CLINICAL QUESTION/LEVEL OF EVIDENCE Therapeutic, III.
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Affiliation(s)
- Malke Asaad
- From the Divisions of Plastic Surgery and General Thoracic Surgery, Department of Surgery, Mayo Clinic; and the Mayo Clinic Alix School of Medicine
| | - Amelia Van Handel
- From the Divisions of Plastic Surgery and General Thoracic Surgery, Department of Surgery, Mayo Clinic; and the Mayo Clinic Alix School of Medicine
| | - Arya A Akhavan
- From the Divisions of Plastic Surgery and General Thoracic Surgery, Department of Surgery, Mayo Clinic; and the Mayo Clinic Alix School of Medicine
| | - Tony C T Huang
- From the Divisions of Plastic Surgery and General Thoracic Surgery, Department of Surgery, Mayo Clinic; and the Mayo Clinic Alix School of Medicine
| | - Aashish Rajesh
- From the Divisions of Plastic Surgery and General Thoracic Surgery, Department of Surgery, Mayo Clinic; and the Mayo Clinic Alix School of Medicine
| | - Mark A Allen
- From the Divisions of Plastic Surgery and General Thoracic Surgery, Department of Surgery, Mayo Clinic; and the Mayo Clinic Alix School of Medicine
| | - K Robert Shen
- From the Divisions of Plastic Surgery and General Thoracic Surgery, Department of Surgery, Mayo Clinic; and the Mayo Clinic Alix School of Medicine
| | - Basel Sharaf
- From the Divisions of Plastic Surgery and General Thoracic Surgery, Department of Surgery, Mayo Clinic; and the Mayo Clinic Alix School of Medicine
| | - Steven L Moran
- From the Divisions of Plastic Surgery and General Thoracic Surgery, Department of Surgery, Mayo Clinic; and the Mayo Clinic Alix School of Medicine
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Winton AJ, Baptiste JL, Allen MA. A versatile expression vector for the growth and amplification of unmodified phage display polypeptides. Protein Expr Purif 2018; 149:31-36. [DOI: 10.1016/j.pep.2018.04.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 04/12/2018] [Accepted: 04/13/2018] [Indexed: 11/29/2022]
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Allen MA, Barannikova E, Riley S, Winton A. Naturally Synthetic: Using Biology to Improve Technology. Biophys J 2015. [DOI: 10.1016/j.bpj.2014.11.3449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Usselman RJ, Russek SE, Klem MT, Allen MA, Douglas T, Young M, Idzerda YU, Singel DJ. Temperature dependence of electron magnetic resonance spectra of iron oxide nanoparticles mineralized in Listeria innocua protein cages. J Appl Phys 2012; 112:84701. [PMID: 23152643 PMCID: PMC3487924 DOI: 10.1063/1.4757964] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Accepted: 09/12/2012] [Indexed: 05/29/2023]
Abstract
Electron magnetic resonance (EMR) spectroscopy was used to determine the magnetic properties of maghemite (γ-Fe(2)O(3)) nanoparticles formed within size-constraining Listeria innocua (LDps)-(DNA-binding protein from starved cells) protein cages that have an inner diameter of 5 nm. Variable-temperature X-band EMR spectra exhibited broad asymmetric resonances with a superimposed narrow peak at a gyromagnetic factor of g ≈ 2. The resonance structure, which depends on both superparamagnetic fluctuations and inhomogeneous broadening, changes dramatically as a function of temperature, and the overall linewidth becomes narrower with increasing temperature. Here, we compare two different models to simulate temperature-dependent lineshape trends. The temperature dependence for both models is derived from a Langevin behavior of the linewidth resulting from "anisotropy melting." The first uses either a truncated log-normal distribution of particle sizes or a bi-modal distribution and then a Landau-Liftshitz lineshape to describe the nanoparticle resonances. The essential feature of this model is that small particles have narrow linewidths and account for the g ≈ 2 feature with a constant resonance field, whereas larger particles have broad linewidths and undergo a shift in resonance field. The second model assumes uniform particles with a diameter around 4 nm and a random distribution of uniaxial anisotropy axes. This model uses a more precise calculation of the linewidth due to superparamagnetic fluctuations and a random distribution of anisotropies. Sharp features in the spectrum near g ≈ 2 are qualitatively predicted at high temperatures. Both models can account for many features of the observed spectra, although each has deficiencies. The first model leads to a nonphysical increase in magnetic moment as the temperature is increased if a log normal distribution of particles sizes is used. Introducing a bi-modal distribution of particle sizes resolves the unphysical increase in moment with temperature. The second model predicts low-temperature spectra that differ significantly from the observed spectra. The anisotropy energy density K(1), determined by fitting the temperature-dependent linewidths, was ∼50 kJ/m(3), which is considerably larger than that of bulk maghemite. The work presented here indicates that the magnetic properties of these size-constrained nanoparticles and more generally metal oxide nanoparticles with diameters d < 5 nm are complex and that currently existing models are not sufficient for determining their magnetic resonance signatures.
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Hess GT, Cragnolini JJ, Popp MW, Allen MA, Dougan SK, Spooner E, Ploegh HL, Belcher AM, Guimaraes CP. M13 bacteriophage display framework that allows sortase-mediated modification of surface-accessible phage proteins. Bioconjug Chem 2012; 23:1478-87. [PMID: 22759232 DOI: 10.1021/bc300130z] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
We exploit bacterial sortases to attach a variety of moieties to the capsid proteins of M13 bacteriophage. We show that pIII, pIX, and pVIII can be functionalized with entities ranging from small molecules (e.g., fluorophores, biotin) to correctly folded proteins (e.g., GFP, antibodies, streptavidin) in a site-specific manner, and with yields that surpass those of any reported using phage display technology. A case in point is modification of pVIII. While a phage vector limits the size of the insert into pVIII to a few amino acids, a phagemid system limits the number of copies actually displayed at the surface of M13. Using sortase-based reactions, a 100-fold increase in the efficiency of display of GFP onto pVIII is achieved. Taking advantage of orthogonal sortases, we can simultaneously target two distinct capsid proteins in the same phage particle and maintain excellent specificity of labeling. As demonstrated in this work, this is a simple and effective method for creating a variety of structures, thus expanding the use of M13 for materials science applications and as a biological tool.
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Affiliation(s)
- Gaelen T Hess
- The David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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Nuraje N, Dang X, Qi J, Allen MA, Lei Y, Belcher AM. Biotemplated synthesis of perovskite nanomaterials for solar energy conversion. Adv Mater 2012; 24:2885-9. [PMID: 22517374 DOI: 10.1002/adma.201200114] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Revised: 02/17/2012] [Indexed: 05/26/2023]
Abstract
A synthetic method of using genetically engineered M13 virus to mineralize perovskite nanomaterials, particularly strontium titanate (STO) and bismuth ferrite (BFO), is presented. Genetically engineered viruses provide effective templates for perovskite nanomaterials. The virus-templated nanocrystals are small in size, highly crystalline, and show photocatalytic and photovoltaic properties.
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Affiliation(s)
- Nurxat Nuraje
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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Oh D, Dang X, Yi H, Allen MA, Xu K, Lee YJ, Belcher AM. Graphene sheets stabilized on genetically engineered M13 viral templates as conducting frameworks for hybrid energy-storage materials. Small 2012; 8:1006-11. [PMID: 22337601 PMCID: PMC3930169 DOI: 10.1002/smll.201102036] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Indexed: 05/19/2023]
Abstract
Utilization of the material-specific peptide-substrate interactions of M13 virus broadens colloidal stability window of graphene. The homogeneous distribution of graphene is maintained in weak acids and increased ionic strengths by complexing with virus. This graphene/virus conducting template is utilized in the synthesis of energy-storage materials to increase the conductivity of the composite electrode. Successful formation of the hybrid biological template is demonstrated by the mineralization of bismuth oxyfluoride as a cathode material for lithium-ion batteries, with increased loading and improved electronic conductivity.
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Affiliation(s)
- Dahyun Oh
- Department of Materials Science and Engineering, The David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Xiangnan Dang
- Department of Materials Science and Engineering, The David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Hyunjung Yi
- Department of Materials Science and Engineering, The David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Mark A. Allen
- Department of Materials Science and Engineering, The David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Kang Xu
- Electrochemistry Branch, Power & Energy Division, Sensor and Electron Devices, Directorate U. S. Army Research Laboratory, Adelphi, Maryland, 20783, USA
| | - Yun Jung Lee
- Department of Energy Engineering, Hanyang University, Seoul 133-791, Republic of Korea
| | - Angela M. Belcher
- Department of Materials Science and Engineering, The David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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Allen MA, Gray G, Churchyard G, Bekker L, Nchabeleng M, Mlisana K, Metch B, Moodie Z, Roux S, Mathebula M, Bennie T, Kublin J. P14-02. Social impact events in Phambili, the first phase 2B HIV vaccine trial in South Africa. Retrovirology 2009. [PMCID: PMC2767682 DOI: 10.1186/1742-4690-6-s3-p190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Lau C, Swann EM, Gaist P, Allen MA. P15-18. Behavioral and social science in HIV vaccine clinical research: workshop recommendations. Retrovirology 2009. [PMCID: PMC2767714 DOI: 10.1186/1742-4690-6-s3-p219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Allen MA, Goh F, Burns BP, Neilan BA. Bacterial, archaeal and eukaryotic diversity of smooth and pustular microbial mat communities in the hypersaline lagoon of Shark Bay. Geobiology 2009; 7:82-96. [PMID: 19200148 DOI: 10.1111/j.1472-4669.2008.00187.x] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The bacterial, archaeal and eukaryotic populations of nonlithifying mats with pustular and smooth morphology from Hamelin Pool, Shark Bay were characterised using small subunit rRNA gene analysis and microbial isolation. A highly diverse bacterial population was detected for each mat, with 16S rDNA clones related to Actinobacteria, Bacteroidetes, Chloroflexi, Cyanobacteria, Gemmatimonas, Planctomycetes, Alphaproteobacteria, Gammaproteobacteria, Deltaproteobacteria, Verrucomicrobia and candidate division TM6 present in each mat. Spirochaetes were detected in the smooth mat only, whereas candidate division OP11 was only detected in the pustular mat. Targeting populations with specific primers revealed additional cyanobacterial diversity. The archaeal population of the pustular mat was comprised purely of Halobacteriales, whereas the smooth mat contained 16S rDNA clones from the Halobacteriales, two groups of Euryarchaea with no close characterised matches, and the Thaumarchaea. Nematodes and fungi were present in each mat type, with diatom 18S rDNA clones only obtained from the smooth mat, and tardigrade and microalgae clones only retrieved from the pustular mat. Cultured isolates belonged to the Firmicutes, Gammaproteobacteria, Alphaproteobacteria, Bacteroidetes, Actinobacteria, Cyanobacteria, and Halobacteriales. The mat populations were significantly more diverse than those previously reported for Hamelin Pool stromatolites, suggesting specific microbial populations may be associated with the nonlithifying and lithifying microbial communities of Hamelin Pool.
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MESH Headings
- Animals
- Archaea/classification
- Archaea/isolation & purification
- Australia
- Bacteria/classification
- Bacteria/isolation & purification
- Biodiversity
- DNA, Ribosomal/chemistry
- DNA, Ribosomal/genetics
- Fungi/classification
- Fungi/isolation & purification
- Geologic Sediments/microbiology
- Geologic Sediments/parasitology
- Molecular Sequence Data
- Nematoda/classification
- Nematoda/isolation & purification
- Phylogeny
- RNA, Archaeal
- RNA, Bacterial/genetics
- RNA, Fungal/genetics
- RNA, Helminth/genetics
- RNA, Ribosomal, 16S/genetics
- RNA, Ribosomal, 18S/genetics
- Sequence Analysis, DNA
- Sequence Homology, Nucleic Acid
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Affiliation(s)
- M A Allen
- School of Biotechnology and Biomolecular Science, University of New South Wales, Sydney, 2052, Australia
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Wiedenheft B, Flenniken ML, Allen MA, Young M, Douglas T. Bioprospecting in high temperature environments; application of thermostable protein cages. Soft Matter 2007; 3:1091-1098. [PMID: 32900030 DOI: 10.1039/b705678h] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The first researchers to discover life in high temperature environments could not have anticipated the impact of their findings on the biotechnology industry. Today biotech companies benefit from multimillion dollar sales of enzymes originating from microorganisms that thrive in diverse high temperature environments. In this review we highlight significant advances made towards the development of self-assembling oligomeric protein cages from hyperthermophilic organisms as amenable platforms for diverse applications in biotechnology, electronics and medicine.
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Affiliation(s)
- Blake Wiedenheft
- Center for Bio-Inspired Nanomaterials and the Thermal Biology Institute, Montana State University, Bozeman, MT 59717, USA.
| | - Michelle L Flenniken
- Center for Bio-Inspired Nanomaterials and the Thermal Biology Institute, Montana State University, Bozeman, MT 59717, USA.
| | - Mark A Allen
- Center for Bio-Inspired Nanomaterials and the Thermal Biology Institute, Montana State University, Bozeman, MT 59717, USA.
| | - Mark Young
- Center for Bio-Inspired Nanomaterials and the Thermal Biology Institute, Montana State University, Bozeman, MT 59717, USA.
| | - Trevor Douglas
- Center for Bio-Inspired Nanomaterials and the Thermal Biology Institute, Montana State University, Bozeman, MT 59717, USA.
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Abstract
We performed multiple analyses of Tyrannosaurus rex (specimen MOR 1125) fibrous cortical and medullary tissues remaining after demineralization. The results indicate that collagen I, the main organic component of bone, has been preserved in low concentrations in these tissues. The findings were independently confirmed by mass spectrometry. We propose a possible chemical pathway that may contribute to this preservation. The presence of endogenous protein in dinosaur bone may validate hypotheses about evolutionary relationships, rates, and patterns of molecular change and degradation, as well as the chemical stability of molecules over time.
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Affiliation(s)
- Mary Higby Schweitzer
- Department of Marine, Earth and Atmospheric Sciences, North Carolina State University, Raleigh, NC 27695, USA.
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Leuko S, Goh F, Allen MA, Burns BP, Walter MR, Neilan BA. Analysis of intergenic spacer region length polymorphisms to investigate the halophilic archaeal diversity of stromatolites and microbial mats. Extremophiles 2006; 11:203-10. [PMID: 17082971 DOI: 10.1007/s00792-006-0028-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2006] [Accepted: 08/16/2006] [Indexed: 10/24/2022]
Abstract
Hamelin Pool in Western Australia is one of the two major sites in the world with active marine stromatolite formation. Surrounded by living smooth and pustular mats, these ancient laminated structures are associated with cyanobacterial communities. Recent studies have identified a wide diversity of bacteria and archaea in this habitat. By understanding and evaluating the microbial diversity of this environment we can obtain insights into the formation of early life on Earth, as stromatolites have been dated in the geological record as far back as 3.5 billion years. Automated ribosomal intergenic spacer analysis (ARISA) patterns were shown to be a useful method to genetically discriminate halophilic archaea within this environment. Patterns of known halophilic archaea are consistent, by replicate analysis, and the halophilic strains isolated from stromatolites have novel intergenic spacer profiles. ARISA-PCR, performed directly on extracted DNA from different sample sites, provided significant insights into the extent of previous unknown diversity of halophilic archaea within this environment. Cloning and sequence analysis of the spacer regions obtained from stromatolites confirmed the novel and broad diversity of halophilic archaea in this environment.
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Affiliation(s)
- S Leuko
- Australian Centre for Astrobiology, Biotechnology Research Institute, Macquarie University, NSW 2109, Sydney, Australia
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Abstract
In 1969, five cases of melioidosis in three separate outbreaks were diagnosed in nonhuman primates in the United States. In the first outbreak, two stump-tailed macaque monkeys (Macaca arctoides) developed signs of the disease approximately 6 months after purchase. A third animal, a chimpanzee (Pan troglodytes), probably acquired its infection from one of these monkeys. Two other unrelated cases involving a pig-tailed monkey (Macaca nemestrina) and a rhesus monkey (Macaca mulatta) were diagnosed. These monkeys had been imported 3 years and 6 months, respectively, prior to the recognized onset of their disease. These cases represent the first known occurrences of spontaneous melioidosis in nonhuman primates in the United States.
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Affiliation(s)
- A F Kaufmann
- Epidemiology Program, National Communicable Disease Center, HSMHA, PHS, USDHEW, Atlanta, Georgia 30333, USA
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Abstract
The authors describe a previously unreported adjunctive passive provocative maneuver that has been found to clinically reproduce the intensity of symptoms in patients diagnosed with disorders of the sesamoids. This test is useful for the initial diagnosis as well as monitoring response to treatment.
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Affiliation(s)
- M A Allen
- The Orthopeadic Surgical Associates of San Antonio, TX 78240, USA.
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Gambhir SS, Gupta P, Shepherd JE, Allen MA, Hoh C, Maddahi J, Phelps ME. MD@: a physician-friendly decision analysis tool. MD Comput 1998; 15:40-8. [PMID: 9458662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The cost-effective use of medical resources is increasingly important in justifying strategies for medical diagnosis and management. Although some software is available to help with decision analysis, it can be difficult to use these tools for medical applications. We have developed a prototype package for modeling various medical decision strategies, which can be used with a Macintosh or Windows-based personal computer. The system is graphically based, intuitive, and user-friendly. The user constructs decision trees for comparing alternative strategies for diagnosis and management. Selecting blocks from a library, the user sets mean values for variables such as prevalence, sensitivity, specificity, cost, morbidity, and mortality. The system then generates the probabilities of various pathways, using Bayesian analysis, without requiring the user to enter equations. It displays the best strategy in terms of a particular criterion and, when appropriate, performs sensitivity analysis.
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Affiliation(s)
- S S Gambhir
- Crump Institute for Biological Imaging, UCLA School of Medicine 90095-1770, USA.
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Abstract
Adrenomedullin (ADM) circulates in the blood at concentrations comparable to other vasoactive peptides with established roles in cardiovascular regulation. Intravenously administered ADM produces a clear hypotensive effect, whereas intracerebroventricular microinjections result in increases in blood pressure (BP). Recently, we demonstrated that ADM influences neurons of the area postrema (AP), a central nervous system site implicated in cardiovascular control. However, to address directly the physiological significance of the actions of ADM at the AP, an in vivo microinjection study was undertaken. ADM, at two concentrations (1 and 10 microM), in volumes of 50, 100, and 200 nl, was microinjected into the AP or NTS of 21 urethan-anesthetized male Sprague-Dawley rats. Microinjection of 10 microM ADM (100 nl) resulted in significant transient (2-5 min) increases in BP [120 s area under the curve (AUC): 684.3 +/- 268.6 mmHg/s (P < 0.05)], and heart rate (HR) [AUC: 12.5 +/- 4.5 beats/min (P < 0.05)]. The lower concentration of ADM (1 microM) had no effect on either BP (179.1 +/- 143.6 mmHg/s) or HR (0.8 +/- 2.6 beats/min). ADM was also microinjected into the immediately adjacent nucleus of the solitary tract, where it was found to be without effect on either BP or HR. This study demonstrates, for the first time, a physiological role for ADM acting at a specific brain site, the AP, to produce significant cardiovascular responses.
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Affiliation(s)
- M A Allen
- Department of Physiology, Queen's University, Kingston, Ontario, Canada
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Allen MA, Brindley J, Merkin JH, Pilling MJ. Autocatalysis in a shear flow. Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics 1996; 54:2140-2142. [PMID: 9965300 DOI: 10.1103/physreve.54.2140] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Abstract
Adrenomedullin (ADM) is a recently discovered 52-amino acid peptide that exerts potent vasodilatory effects in the periphery and influences the control of body fluid balance when injected centrally. In this study extracellular single-unit recordings were obtained from 94 AP neurons in rat brain slices. Bath application of ADM (10(-7) M) excited 47% (32 of 68) of cells tested, and these effects were found to be dose dependent from 10(-7) to 10(-9) M. Excitation was maintained during synaptic blockade in a low-Ca2+ artificial cerebrospinal fluid solution, demonstrating direct actions of ADM on these neurons. The remaining cells were either unaffected (n = 25) or inhibited (n = 11) by ADM. ADM (10(-7) M) also influenced the spontaneous activity of 9 (7 inhibited, 2 excited) of 16 neurons located in the nucleus tractus solitarii (NTS). However, these effects could be eliminated during synaptic blockade, suggesting indirect actions of the peptide on NTS neurons. These data demonstrate that a specific population of CNS neurons within the AP are directly influenced by ADM and suggest that ADM may exert its effects on the central control of fluid balance through direct actions at this circumventricular organ.
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Affiliation(s)
- M A Allen
- Department of Physiology, Queen's University, Kingston, Ontario, Canada
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Allen MA. PPD testing following BCG vaccination. J Assoc Nurses AIDS Care 1992; 3:47. [PMID: 1554884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Allen MA, Lynch MM. Experiences with anaerobes. Med Lab Sci 1990; 47:337-46. [PMID: 2283937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Anaerobiology has long been an underdeveloped entity in the routine clinical microbiology laboratory. The difficulties and successes in setting up this specialist department in such a laboratory are outlined. It is concluded that specimen quality, technical expertise, taxonomy and identification remain the areas which need most attention.
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Affiliation(s)
- M A Allen
- Microbiology Dept., St. James's Hospital, Dublin, Republic of Ireland
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Bell CA, Hall JE, Kyle DE, Grogl M, Ohemeng KA, Allen MA, Tidwell RR. Structure-activity relationships of analogs of pentamidine against Plasmodium falciparum and Leishmania mexicana amazonensis. Antimicrob Agents Chemother 1990; 34:1381-6. [PMID: 2201254 PMCID: PMC175985 DOI: 10.1128/aac.34.7.1381] [Citation(s) in RCA: 80] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The antiprotozoal compound 1,5-di(4-amidinophenoxy)pentane (pentamidine) and 36 of its analogs were screened for in vitro activity against Leishmania mexicana amazonensis clone 669 C4S (MHOM/BR/73/M2269) and Plasmodium falciparum clones W2 (Indochina III/CDC) and D6 (Sierra Leone I/CDC). Pentamidine and each of the analogs tested exhibited activity in vitro against L. m. amazonensis and P. falciparum. The pentamidine analogs were more effective against the P. falciparum clones than against L. m. amazonensis. P. falciparum was extremely susceptible to these compounds, with 50% inhibitory concentrations as low as 0.03 microM. While none of the analogs exhibited marked improvement in antileishmanial activity compared with pentamidine, 12 of the pentamidine analogs showed activity approximately equal to or greater than that of the parent compound. From the promising activity exhibited by the pentamidine analogs in this in vitro study and their potential for reduced toxicity relative to the parent drug, pentamidine-related compounds hold promise as new agents for the treatment of protozoal infections.
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Affiliation(s)
- C A Bell
- Department of Parasitology, School of Public Health, University of North Carolina, Chapel Hill 27599
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Jones SK, Hall JE, Allen MA, Morrison SD, Ohemeng KA, Reddy VV, Geratz JD, Tidwell RR. Novel pentamidine analogs in the treatment of experimental Pneumocystis carinii pneumonia. Antimicrob Agents Chemother 1990; 34:1026-30. [PMID: 2393262 PMCID: PMC171751 DOI: 10.1128/aac.34.6.1026] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
We have recently demonstrated that substitution of imidazoline moieties for the amidine groups of pentamidine produces a molecule that is effective against rat Pneumocystis carinii pneumonia and that is apparently less toxic than pentamidine. For this reason, 10 novel imidazoline substituted compounds were evaluated for their effect against rat P. carinii pneumonia. While several of the new compounds were observed to have advantages over pentamidine in the treatment of disease in the rat model, only one compound stood out as a potential new clinical agent. Treatment for 2 weeks with intravenous (i.v.) doses of 1,3-di(4-imidazolino-2-methoxyphenoxy)propane (DIMP) at 1 mg/kg per day produced an anti-P. carinii pneumonia effect equivalent to i.v. doses of pentamidine at 10 mg/kg per day. Although pentamidine and one of the test drugs, 1,3-di(4-imidazolinophenoxy)propane, showed no activity against P. carinii pneumonia when administered per os, DIMP exhibited potent anti-P. carinii pneumonia activity when given by daily gavage doses of 40 and 25 mg/kg. DIMP retained significant activity when given every other day by a gavage dose of 25 mg/kg. No toxicity was observed with the drug at any of the dose levels or by either of the routes of administration. However, the low solubility of the drug prevented testing at higher i.v. doses. Our conclusion is that DIMP has the potential of providing a safer and more effective alternative to pentamidine for the treatment of P. carinii pneumonia.
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Affiliation(s)
- S K Jones
- Department of Pediatric Infectious Disease, School of Medicine, University of North Carolina, Chapel Hill 27599
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Allen MA, Boyd JK, Callin RS, Deruyter H, Eppley KR, Fant KS, Fowkes WR, Haimson J, Hoag HA, Hopkins DB, Houck T, Koontz RF, Lavine TL, Loew GA, Mecklenburg B, Miller RH, Ruth RD, Ryne RD, Sessler AM, Vlieks AE, Wang JW, Westenskow GA, Yu SS. High-gradient electron accelerator powered by a relativisitic klystron. Phys Rev Lett 1989; 63:2472-2475. [PMID: 10040897 DOI: 10.1103/physrevlett.63.2472] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Abrams GS, Adolphsen CE, Aleksan R, Alexander JP, Allen MA, Atwood WB, Averill D, Ballam J, Bambade P, Barish BC, Barklow T, Barnett BA, Bartelt J, Bethke S, Blockus D, Bonvicini G, Boyarski A, Brabson B, Breakstone A, Breidenbach M, Brom JM, Brown JL, Brown KL, Bulos F, Burchat PR, Burke DL, Cence RJ, Chapman J, Chmeissani M, Clendenin J, Cords D, Coupal DP, Dauncey P, Dean NR, DeStaebler HC, Dorfan DE, Dorfan JM, Drell PS, Drewer DC, Dydak F, Ecklund S, Elia R, Erickson RA, Fay J, Feldman GJ, Fernandes D, Field RC, Fieguth TH, Fischer GE, Ford WT, Fordham C, Frey R, Fujino D, Gan KK, Gatto C, Gero E, Gidal G, Glanzman T, Goldhaber G, Gratta G, Grindhammer G, Grosse-Wiesmann P. Initial measurements of Z-boson resonance parameters in e+e- annihilation. Phys Rev Lett 1989; 63:724-727. [PMID: 10041161 DOI: 10.1103/physrevlett.63.724] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Sheehan JD, Duffy MJ, Allen MA, Fennelly JJ. CA 125 as a tumour marker in epithelial ovarian cancer. Ir J Med Sci 1989; 158:10-3. [PMID: 2737852 DOI: 10.1007/bf02942008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
CA 125, a high molecular weight glycoprotein, was measured in sera from patients with epithelial ovarian cancer, patients with benign gynaecological disease and in patients with non-ovarian adenocarcinomas. High levels (greater than 35 U/ml) were found in 48/50 patients with active ovarian cancer but in only 3/26 patients who had an ovarian cancer previously diagnosed but who were apparently disease free. 6/23 patients with non-ovarian adenocarcinomas as well as 4/18 patients with benign gynaecological disease also had elevated levels. CA 125 levels were higher in serious than non-serous ovarian cancers and tended to increase with increasing stage. In all of 19 patients with ovarian cancer who responded to treatment CA 125 levels fell while 17/20 with progressive disease showed a rise. In 7/8 patients, serial determination of CA 125 showed a rise before the clinical detection of recurrence, the median lead-time being 3.5 months. We conclude that CA 125 is an excellent marker in the management of patients with epithelial ovarian cancers.
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Taher MF, Cecchini AB, Allen MA, Gobran SR, Gorman RC, Guthrie BL, Lingenfelter KA, Rabbany SY, Rolchigo PM, Melbin J. Baroreceptor responses derived from a fundamental concept. Ann Biomed Eng 1988; 16:429-43. [PMID: 3189973 DOI: 10.1007/bf02368008] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
A model is presented that relates the change in baroreceptor firing rate to a step change in blood pressure. This relationship is nonlinear since the alteration in rate of firing depends on the current rate of firing. It is shown that this simple relationship embodies all currently established baroreceptor response modes. The model needs refinement to allow for effects arising from the properties of the tissue matrix in which the receptors are embedded. Further analysis is precluded at present owing to paucity of quantitative experimental data.
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Affiliation(s)
- M F Taher
- Department of Bioengineering, University of Pennsylvania, Philadelphia 19104
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Allen MA, Lalor SB, English LF, Mulvihill E. Acid-fast smears: a cause of false positive reactions. Med Lab Sci 1988; 45:184-6. [PMID: 3210925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Duffy MJ, O'Connell M, O'Sullivan F, McKenna B, Allen MA, McDonnell L. CEA-like material in cytosols from human breast carcinomas. Correlation with biochemical and pathologic parameters. Cancer 1983; 51:121-3. [PMID: 6295590 DOI: 10.1002/1097-0142(19830101)51:1<121::aid-cncr2820510124>3.0.co;2-l] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
CEA-like material was found in 51 of 62 primary human breast carcinomas and in only 2 of 12 fibroadenomas. Levels of carcinoma CEA-like material correlated weakly with cytoplasmic estradiol receptor levels, total cytosol estrogens, and cytosol progesterone. Levels of CEA-like material showed no significant correlation with carcinoma stage, grade, cellularity, size or histologic type. Levels, however, correlated inversely with lymphocyte infiltration.
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Allen MA. Production of a videotape. Nurs Times 1981; 77:915-6. [PMID: 6909808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Allen MA, Wrenn JM, Borzelleca JF. A study of the mechanism of transport of benzylpenicillin in the rat submaxillary gland. Arch Int Pharmacodyn Ther 1978; 233:180-91. [PMID: 28702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In vitro studies performed on slices of rat submaxillary gland to evaluate uptake and efflux of 14C-benzylpenicillin (10(-6)M, 10(-5)M) showed that uptake of 14C-benzylpenicillin was not significantly altered by aeration with N2, addition of 10(-5)M CN- or 10(-3) M probenecid, or substitution of K2SO4 in place of NaCl in the KRT buffer to produce a depolarizing solution. Lowering the extracellular pH (pHe) resulted in increases rates of uptake and efflux, whereas increasing the pHe resulted in decreased rates. The in vivo uptake of penicillin into whole glands excised from rates treated in vivo was very similar to that seen in the slice preparation. However, addition of probenecid to salivary gland slices in vitro decreased the rate of effux. These data suggest that the movement of penicillin in the rat salivary gland may occur by a two-step mechanism: (1) passive exchange of penicillin into the gland dependent on the degree of dissociation of penicillin, and (2) active excretion of the drug from the gland by a transport mechanism similar to that of the kidney densitive to probenecid.
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Abstract
The rate constant for the hydrolysis of prostacyclin (PGI2) to 6-keto-PGF1alpha was measured by monitoring the UV spectral change, over a pH range 6 to 10 at 25 degrees C and the total ionic strength of 0.5 M. The first-order rate constant (kdegreesobs) extrapolated to zero buffer concentration follows an expression, kdegreesobs = kH+ (H+), where kH+ is a second-order rate constant for the specific acid catalyzed hydrolysis. The value of kH+ obtained (3.71 x 10(4) sec-1 M-1) Is estimated approximately 700-fold greater than a kH+ value expected from the hydrolysis of other vinyl ethers. Such an unusually high reactivity of PGI2 even for a vinyl ether is attributed to a possible ring strain release that would occur upon the rate controlling protonation of C5. A Brønsted slope (alpha) of 0.71 was obtained for the acid (including H3O+) catalytic constants, from which a pH independent first-order rate constant for the spontaneous hydrolysis (catalyzed by H2O as a general acid) was estimated to be 1.3 x 10(-6) sec-1. An apparent activation energy (Ea) of 11.85 Kcal/mole was obtained for the hydrolysis at pH 7.48, from which a half-life of PGI2 at 4 degrees C was estimated to be approximately 14.5 min. when the total phosphate concentration is 0.165 M (cf. 3.5 min. at 25 degrees C).
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Stenchever MA, Allen MA, Jerominski L, Petersen RV. Effects of bis(2-ethylhexyl) phthalate on chromosomes of human leukocytes and human fetal lung cells. J Pharm Sci 1976; 65:1648-51. [PMID: 993999 DOI: 10.1002/jps.2600651121] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Blood from two male and two female donors was exposed at 37degrees for 4 hr to concentrations of 60.0, 6.0, 0.6, and 0.06 mug of a widely used plasticizer, bis (2-ethylhexyl) phthalate, per milliliter of blood. The bis(2-ethylhexyl) phthalate was solubilized with polysorbate 80. Appropriate polysorbate and nonpolysorbate controls also were established. Following the 4 hr of incubation, phytohemagglutinin was added and tissue cultures were established. In addition, human fetal lung cells were exposed in tissue culture to a medium containing 6.0 mug/ml of bis(2-ethylhexyl) phthalate in polysorbate 80 for 5 days. Similar controls also were established for these experiments. Analysis of chromosome preparations from all cultures obtained failed to show any increased evidence of isochromatid and chromatid breaks or gaps or abnormal forms at any studied concentration when compared to the control cultures. In addition, analysis of fetal lung cell preparations for aneuploidy failed to reveal any differences between cells from study and control cultures. This study involved a short-term exposure to bis(2-ethylhexyl) phthalate in various concentrations which did not cause damage in leukocytes or fetal lung cells.
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Allen MA, Wrenn JM, Putney JW, Borzelleca JF. A study of the mechanism of transport of diphenylhydantoin in the rat submaxillary gland in vitro. J Pharmacol Exp Ther 1976; 197:408-13. [PMID: 5599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
In vitro studies performed on rat submaxillary gland slices with diphenylhydantoin (6 X 10(-6) M) showed that variations of extracellular pH (pHe) had no significant effects on uptake and only slight effects on efflux (lowering the pHe slightly decreased efflux rates, whereas increasing pHe slightly increased efflux rates). Increasing diphenylhydantoin concentration significantly decreased uptake and slightly increased the rate of efflux. Uptake of 14C-diphenylhydantoin was significantly decreased when compared to control conditions (pH 7.40, 37 degrees C, 100% O2 aeration, 6 X 10(-6) M) by the following alterations: aeration of the incubation medium with N2 instead of O2, decrease of bath temperature from 37 degrees C to 5 degrees C and addition of the following metabolic inhibitors: iodoacetic acid (10(-3)M), 2,4-dinitrophenol (10(-3)M) and cyanide (10(-3)M). Probenecid (10(-3)M) had no significant effect on diphenylhydantoin uptake when compared to control values. No evidence of salivary biotransformation of diphenylhydantoin was seen in the in vitro system using thin-layer chromatography. These in vitro data suggest an active transport process that is concentration-dependent with a possible saturable binding site on the membrane or in the interior of the cell.
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