1
|
Morris DP, Snipes LC, Hill SA, Woods MM, Mbugua MM, Wade LR, McMurry JL. Corrigendum: A reversible cell penetrating peptide-cargo linkage allows dissection of cell penetrating peptide-and cargo- dependent effects on internalization and identifies new functionalities of putative endolytic peptides. Front Pharmacol 2023; 14:1152506. [PMID: 37144219 PMCID: PMC10152549 DOI: 10.3389/fphar.2023.1152506] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 03/30/2023] [Indexed: 05/06/2023] Open
Abstract
[This corrects the article DOI: 10.3389/fphar.2022.1070464.].
Collapse
|
2
|
Morris DP, Snipes LC, Hill SA, Woods MM, Mbugua MM, Wade LR, McMurry JL. A reversible cell penetrating peptide-cargo linkage allows dissection of cell penetrating peptide- and cargo-dependent effects on internalization and identifies new functionalities of putative endolytic peptides. Front Pharmacol 2022; 13:1070464. [PMID: 36479201 PMCID: PMC9720253 DOI: 10.3389/fphar.2022.1070464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 11/09/2022] [Indexed: 11/23/2022] Open
Abstract
Cell penetrating peptides (CPPs) are a promising technology for therapeutic delivery of macromolecular cargos. CPPs have generally used covalent linkages to cargo, ensuring a common fate as one molecule. Conversely, our CPP-adaptor, TAT-CaM, noncovalently binds calmodulin binding sequence (CBS)-containing cargos in calcium rich media then dissociates in the calcium-poor endosomal environment following internalization, enhancing endosomal escape relative to standard CPPs. In this study, we report cell entry of positively charged protein cargos that were not increased by TAT-CaM while cargos based on the negatively charged maltose binding protein (MBP) displayed little intrinsic internalization but were internalized by TAT-CaM. In addition, association of positively charged proteins with negatively charged nucleic acids reduced internalization. This evidence points to the dominant role cargo charge plays in apparent CPP effectiveness. There has been little systematic investigation as to how interaction between CPPs and cargos impacts internalization efficiency. Our adaptors provide a tool that allows combinatorial assays to detect emergent properties. Toward this end we added 4 endolytic peptide (EP) sequences between cargo CBS and MBP moieties to create 4 new cargos and between TAT and CaM to create 4 new adaptors. The new cargos were assayed for internalization alone and with a panel of CPP-adaptors to identify combinations that displayed increased internalization efficiency or other properties. Among the most important results, addition of the EP LAH4 improved adaptor performance and provided some CPP capability to cargos. MBP-LAH4-CBS was internalized more effectively by most adaptors, suggesting this sequence has general stimulatory ability. Two other EPs, Aurein 1.2 and HA2, also provided some CPP capability to their MBP cargos but were unexpectedly antagonistic to internalization by most adaptors due to retention of adaptor/cargo complexes on the cell surface. We thus identified LAH4 as stimulator of internalization in both adaptors and cargos and uncovered new functionality for Aurein 1.2 and HA2, which may be related to their identification as EPs. Future experiments will test new endolytic capabilities made possible with combinatorial approaches.
Collapse
|
3
|
Allen GP, Deao KM, Hill SA, Schipelliti SM, Tran T. In vitro evaluation of antimicrobial resistance selection in Neisseria gonorrhoeae. Int J Antimicrob Agents 2021; 58:106417. [PMID: 34391903 DOI: 10.1016/j.ijantimicag.2021.106417] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 07/26/2021] [Accepted: 08/06/2021] [Indexed: 11/19/2022]
Abstract
Gonococcal infections represent an urgent public-health threat as >50% of cases caused by Neisseria gonorrhoeae strains display reduced susceptibility to at least one antimicrobial agent. We evaluated the pharmacodynamics of a number of antimicrobials against N. gonorrhoeae in order to assess the likelihood of mutant selection by these agents. The mutant prevention concentration (MPC) and mutant selection window (MSW) were determined for azithromycin, ceftriaxone, doxycycline, ertapenem, gentamicin, ciprofloxacin, levofloxacin and moxifloxacin against a wild-type strain of N. gonorrhoeae (ATCC 49226) and a gyrA mutant of ATCC 49226. Pharmacokinetic parameters, including peak concentration (Cmax), half-life (t1/2) and area under the plasma concentration-time curve over 24 h (AUC), associated with each agent were used to calculate the time within the MSW (TMSW, percentage of the dosing interval that antimicrobial concentrations fall within the MSW), Cmax/MPC ratio and AUC/MPC ratio for each antimicrobial agent. Concentrations of ceftriaxone (500 mg), ertapenem, ciprofloxacin, levofloxacin and moxifloxacin surpass the MPC for both strains. Results of pharmacodynamic analyses suggest that ertapenem, ciprofloxacin, levofloxacin and moxifloxacin may be most likely to prevent mutant selection in N. gonorrhoeae. Use of ceftriaxone, azithromycin, doxycycline or gentamicin for gonorrhoea is expected to lead to the ongoing emergence of resistance to these agents. There is a clear need to develop novel treatment regimens for gonococcal infections in order to limit the dissemination of resistance in N. gonorrhoeae.
Collapse
Affiliation(s)
- George P Allen
- School of Pharmacy, Westbrook College of Health Professions, University of New England, 716 Stevens Avenue, Portland, ME 04103, USA.
| | - Kristina M Deao
- School of Pharmacy, Westbrook College of Health Professions, University of New England, 716 Stevens Avenue, Portland, ME 04103, USA
| | - Stephanie A Hill
- School of Pharmacy, Westbrook College of Health Professions, University of New England, 716 Stevens Avenue, Portland, ME 04103, USA
| | - Sandra M Schipelliti
- School of Pharmacy, Westbrook College of Health Professions, University of New England, 716 Stevens Avenue, Portland, ME 04103, USA
| | - Thomas Tran
- School of Pharmacy, Westbrook College of Health Professions, University of New England, 716 Stevens Avenue, Portland, ME 04103, USA
| |
Collapse
|
4
|
A Hill S, Dawood A, Boland E, Leahy HE, Em Murtagh F. Palliative medicine in the intensive care unit: needs, delivery, quality. BMJ Support Palliat Care 2021; 12:38-41. [PMID: 33602723 DOI: 10.1136/bmjspcare-2020-002795] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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: 11/10/2020] [Revised: 02/04/2021] [Accepted: 02/08/2021] [Indexed: 11/03/2022]
Abstract
BACKGROUND 15%-20% of critical care patients die during their hospital admission. This service evaluation assesses quality of palliative care in intensive care units (ICUs) compared with national standards. METHODS Retrospective review of records for all patients who died in four ICUs (irrespective of treatment limitation) between 1 June and 31 July 2019. Descriptive statistics reported for patient characteristics, length of stay, admission route, identification triggers and palliative care delivery. RESULTS Forty-five patients died, two records were untraced, thus N=43. The dying process was recognised in 88% (n=38). Among those where dying was recognised (N=35), 97% (34) had documented family discussion before death, 9% (3) were offered religious/spiritual support, 11% (4) had review of hydration/nutrition and 6% (2) had documented preferred place of death. Prescription of symptom control medications was complete in 71% (25) opioids, 34% (12) haloperidol, 54% (19) midazolam and 43% (15) hyoscine. Combining five triggers-length of stay >10 days prior to ICU admission 7% (3), multiorgan failure ≥3 systems 33% (14), stage IV malignancy 5% (2), post-cardiac arrest 23% (10) and intracerebral haemorrhage requiring mechanical ventilation 12% (5)-identified 60% (26) of patients. Referral to the palliative care team was seen in 14% (5), and 8% (3) had specialist palliative care team review. CONCLUSIONS Recognition of dying was high but occurred close to death. Family discussions were frequent, but religious/spiritual needs, hydration/nutrition and anticipatory medications were less often considered. The ICUs delivered their own palliative care in conjunction with specialist palliative care input. Combining five triggers could increase identification of palliative care needs, but a larger study is needed.
Collapse
Affiliation(s)
- Stephanie A Hill
- Intensive Care Unit, Hull University Teaching Hospitals NHS Trust, Hull, Kingston upon Hull, UK
| | - Abdul Dawood
- Intensive Care Unit, Hull University Teaching Hospitals NHS Trust, Hull, Kingston upon Hull, UK
| | - Elaine Boland
- Palliative Medicine, Hull and East Yorkshire Hospitals NHS Trust, Hull, UK
| | - Hannah E Leahy
- Palliative Medicine, Hull and East Yorkshire Hospitals NHS Trust, Hull, UK
| | - Fliss Em Murtagh
- Wolfson Palliative Care Research Centre, University of Hull, Hull, Kingston upon Hull, UK
| |
Collapse
|
5
|
Hill SA, Waring WS. Pharmacological effects and safety monitoring of anabolic androgenic steroid use: differing perceptions between users and healthcare professionals. Ther Adv Drug Saf 2019; 10:2042098619855291. [PMID: 31223471 PMCID: PMC6566473 DOI: 10.1177/2042098619855291] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 05/15/2019] [Indexed: 11/24/2022] Open
Abstract
Background: Androgenic anabolic steroids (AASs) have a number of licensed clinical indications but are also subject to abuse within the body building community. They have a number of potentially important adverse pharmacological effects, and users require health monitoring, including selected laboratory investigations. The extent to which AAS users are able to seek medical supervision and the ability of healthcare providers to respond to the needs of users is uncertain. The present study sought to ascertain how AAS abusers interact with healthcare providers, and self-reported knowledge among doctors regarding the healthcare effects and need for monitoring of AAS users. Methods: Questionnaires were administered, and there were 216 respondents among AAS users and 134 doctors. Results: A high proportion of AAS users cited various barriers to accessing healthcare, including 136 of 189 (72%) that reported a fear of reproach, and 107 of 194 (55%) that had avoided seeking medical advice; 137 of 193 respondents (71%) did not disclose AAS use to healthcare professionals. Doctors across a broad range of seniority stated a lack of knowledge of AASs; 130 (97%) had received no formal training, and 109 (82%) did not know which blood tests could be used for safety monitoring. Conclusions: The present study has highlighted some perceptions among the body-building community that create obstacles to them accessing appropriate safety monitoring while using AASs. Doctors may not have adequate knowledge of AASs, which may prevent them giving accurate and complete information. Further work is needed to address the barriers of communication between users and health professionals in order to facilitate better healthcare monitoring and drug safety.
Collapse
|
6
|
Affiliation(s)
- Maria M. Mbugua
- Department of Chemistry & BiochemistryKennesaw State UniversityMariettaGA
| | - Stephanie A. Hill
- Department of Molecular and Cellular BiologyKennesaw State UniversityKennesawGA
| | - Daniel P. Morris
- Department of Molecular and Cellular BiologyKennesaw State UniversityKennesawGA
| | - Jonathan L. McMurry
- Department of Molecular and Cellular BiologyKennesaw State UniversityKennesawGA
| |
Collapse
|
7
|
Tanner SM, Daft JG, Hill SA, Martin CA, Lorenz RG. Altered T-Cell Balance in Lymphoid Organs of a Mouse Model of Colorectal Cancer. J Histochem Cytochem 2016; 64:753-767. [PMID: 27798287 DOI: 10.1369/0022155416672418] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [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: 07/18/2016] [Accepted: 09/06/2016] [Indexed: 12/17/2022] Open
Abstract
The adenomatous polyposis coli (APC) gene is a known tumor suppressor gene, and mice with mutations in Apc (ApcMin/+) spontaneously form multiple intestinal neoplasms. In this model of human colorectal cancer (CRC), it has been reported that CD4+ T-cell-derived interleukin 17 (IL-17) promotes intestinal tumor development, but it is not known if the Apc mutation actually directly alters T-cell function and subsequently tumor immunosurveillance. To investigate the ApcMin/+ mutation on T-cell function, flow cytometric, histochemical, and immunofluorescent studies on both wild-type (Apc+/+) and ApcMin/+ mice were performed. We identified decreased levels of interferon gamma (IFN-γ+)IL-17+ double-positive CD4+ cells in the mesenteric lymph nodes and Peyer's patches of ApcMin/+ mice. In addition, altered levels of CD8+ cells, and changes in CD8+ production of IFN-γ and granzyme B were observed. These T-cell alterations did modify tumor immunosurveillance, as the adoptive transfer of splenocytes from ApcMin/+ animals into a chemically induced CRC model resulted in the inability to prevent epithelial dysplasia. These results suggest an altered T-cell balance in ApcMin/+ mice may disrupt intestinal homeostasis, consequently limiting intestinal tumor immunosurveillance.
Collapse
Affiliation(s)
- Scott M Tanner
- Department of Biological, Physical, and Earth Sciences, Limestone College, Gaffney, South Carolina (SMT).,Division of Pediatric Surgery, Department of Surgery, University of Alabama at Birmingham, Birmingham, Alabama (CAM)
| | - Joseph G Daft
- Department of Natural Sciences and Mathematics, Lee University, Cleveland, Tennessee (JGD)
| | - Stephanie A Hill
- Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama (SAH, RGL)
| | - Colin A Martin
- Division of Pediatric Surgery, Department of Surgery, University of Alabama at Birmingham, Birmingham, Alabama (CAM)
| | - Robin G Lorenz
- Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama (SAH, RGL)
| |
Collapse
|
8
|
McMurry JL, Minamino T, Furukawa Y, Francis JW, Hill SA, Helms KA, Namba K. Weak Interactions between Salmonella enterica FlhB and Other Flagellar Export Apparatus Proteins Govern Type III Secretion Dynamics. PLoS One 2015; 10:e0134884. [PMID: 26244937 PMCID: PMC4526367 DOI: 10.1371/journal.pone.0134884] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 07/14/2015] [Indexed: 11/18/2022] Open
Abstract
The bacterial flagellum contains its own type III secretion apparatus that coordinates protein export with assembly at the distal end. While many interactions among export apparatus proteins have been reported, few have been examined with respect to the differential affinities and dynamic relationships that must govern the mechanism of export. FlhB, an integral membrane protein, plays critical roles in both export and the substrate specificity switching that occurs upon hook completion. Reported herein is the quantitative characterization of interactions between the cytoplasmic domain of FlhB (FlhBC) and other export apparatus proteins including FliK, FlhAC and FliI. FliK and FlhAC bound with micromolar affinity. KD for FliI binding in the absence of ATP was 84 nM. ATP-induced oligomerization of FliI induced kinetic changes, stimulating fast-on, fast-off binding and lowering affinity. Full length FlhB purified under solubilizing, nondenaturing conditions formed a stable dimer via its transmembrane domain and stably bound FliH. Together, the present results support the previously hypothesized central role of FlhB and elucidate the dynamics of protein-protein interactions in type III secretion.
Collapse
Affiliation(s)
- Jonathan L. McMurry
- Department of Molecular & Cellular Biology, Kennesaw State University, Kennesaw, Georgia, United States of America
- * E-mail:
| | - Tohru Minamino
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Yukio Furukawa
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Joshua W. Francis
- Department of Molecular & Cellular Biology, Kennesaw State University, Kennesaw, Georgia, United States of America
| | - Stephanie A. Hill
- Department of Molecular & Cellular Biology, Kennesaw State University, Kennesaw, Georgia, United States of America
| | - Katy A. Helms
- Department of Molecular & Cellular Biology, Kennesaw State University, Kennesaw, Georgia, United States of America
| | - Keiichi Namba
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| |
Collapse
|
9
|
Gruschus JM, Jiang Z, Yap TL, Hill SA, Grishaev A, Piszczek G, Sidransky E, Lee JC. Dissociation of glucocerebrosidase dimer in solution by its co-factor, saposin C. Biochem Biophys Res Commun 2015; 457:561-6. [PMID: 25600808 DOI: 10.1016/j.bbrc.2015.01.024] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [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: 12/23/2014] [Accepted: 01/08/2015] [Indexed: 12/23/2022]
Abstract
Mutations in the gene for the lysosomal enzyme glucocerebrosidase (GCase) cause Gaucher disease and are the most common risk factor for Parkinson disease (PD). Analytical ultracentrifugation of 8 μM GCase shows equilibrium between monomer and dimer forms. However, in the presence of its co-factor saposin C (Sap C), only monomer GCase is seen. Isothermal calorimetry confirms that Sap C associates with GCase in solution in a 1:1 complex (Kd = 2.1 ± 1.1 μM). Saturation cross-transfer NMR determined that the region of Sap C contacting GCase includes residues 63-66 and 74-76, which is distinct from the region known to enhance GCase activity. Because α-synuclein (α-syn), a protein closely associated with PD etiology, competes with Sap C for GCase binding, its interaction with GCase was also measured by ultracentrifugation and saturation cross-transfer. Unlike Sap C, binding of α-syn to GCase does not affect multimerization. However, adding α-syn reduces saturation cross-transfer from Sap C to GCase, confirming displacement. To explore where Sap C might disrupt multimeric GCase, GCase x-ray structures were analyzed using the program PISA, which predicted stable dimer and tetramer forms. For the most frequently predicted multimer interface, the GCase active sites are partially buried, suggesting that Sap C might disrupt the multimer by binding near the active site.
Collapse
Affiliation(s)
- James M Gruschus
- Laboratory of Molecular Biophysics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda MD 20892, United States.
| | - Zhiping Jiang
- Laboratory of Molecular Biophysics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda MD 20892, United States
| | - Thai Leong Yap
- Laboratory of Molecular Biophysics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda MD 20892, United States
| | - Stephanie A Hill
- Laboratory of Molecular Biophysics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda MD 20892, United States
| | - Alexander Grishaev
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, United States
| | - Grzegorz Piszczek
- Biophysics Core, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, United States
| | - Ellen Sidransky
- Section on Molecular Neurogenetics, Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, United States
| | - Jennifer C Lee
- Laboratory of Molecular Biophysics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda MD 20892, United States.
| |
Collapse
|
10
|
Hill SA, Kwa LG, Shammas SL, Lee JC, Clarke J. Mechanism of Assembly of the Non-Covalent Spectrin Tetramerization Domain from Intrinsically Disordered Partners. J Mol Biol 2014; 426:21-35. [PMID: 24055379 PMCID: PMC9082959 DOI: 10.1016/j.jmb.2013.08.027] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Revised: 07/24/2013] [Accepted: 08/20/2013] [Indexed: 01/29/2023]
Abstract
Interdomain interactions of spectrin are critical for maintenance of the erythrocyte cytoskeleton. In particular, “head-to-head” dimerization occurs when the intrinsically disordered C-terminal tail of β-spectrin binds the N-terminal tail of α-spectrin, folding to form the “spectrin tetramer domain”. This non-covalent three-helix bundle domain is homologous in structure and sequence to previously studied spectrin domains. We find that this tetramer domain is surprisingly kinetically stable. Using a protein engineering Φ-value analysis to probe the mechanism of formation of this tetramer domain, we infer that the domain folds by the docking of the intrinsically disordered β-spectrin tail onto the more structured α-spectrin tail.
Collapse
Affiliation(s)
- Stephanie A Hill
- University of Cambridge Chemical Laboratory, Lensfield Road, Cambridge CB2 1EW, UK; Laboratory of Molecular Biophysics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Lee Gyan Kwa
- University of Cambridge Chemical Laboratory, Lensfield Road, Cambridge CB2 1EW, UK
| | - Sarah L Shammas
- University of Cambridge Chemical Laboratory, Lensfield Road, Cambridge CB2 1EW, UK
| | - Jennifer C Lee
- Laboratory of Molecular Biophysics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jane Clarke
- University of Cambridge Chemical Laboratory, Lensfield Road, Cambridge CB2 1EW, UK.
| |
Collapse
|
11
|
Clarke J, Rogers JM, Hill SA, Shammas SL, Gruszka D, Steward A, Lee JC, Potts JR. Folding Upon Binding - Not a Simple Protein Folding Problem. Biophys J 2013. [DOI: 10.1016/j.bpj.2012.11.1069] [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: 11/27/2022] Open
|
12
|
Hill SA, Lee JC, Clarke J. Identity of Hinge Residues Defines Stability and Kinetics of Spectrin Tetramer Interaction. Biophys J 2013. [DOI: 10.1016/j.bpj.2012.11.2052] [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: 10/27/2022] Open
|
13
|
Benoit SL, McMurry JL, Hill SA, Maier RJ. Helicobacter pylori hydrogenase accessory protein HypA and urease accessory protein UreG compete with each other for UreE recognition. Biochim Biophys Acta Gen Subj 2012; 1820:1519-25. [PMID: 22698670 DOI: 10.1016/j.bbagen.2012.06.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Revised: 06/01/2012] [Accepted: 06/04/2012] [Indexed: 01/15/2023]
Abstract
BACKGROUND The gastric pathogen Helicobacter pylori relies on nickel-containing urease and hydrogenase enzymes in order to colonize the host. Incorporation of Ni(2+) into urease is essential for the function of the enzyme and requires the action of several accessory proteins, including the hydrogenase accessory proteins HypA and HypB and the urease accessory proteins UreE, UreF, UreG and UreH. METHODS Optical biosensing methods (biolayer interferometry and plasmon surface resonance) were used to screen for interactions between HypA, HypB, UreE and UreG. RESULTS Using both methods, affinity constants were found to be 5nM and 13nM for HypA-UreE and 8μM and 14μM for UreG-UreE. Neither Zn(2+) nor Ni(2+) had an effect on the kinetics or stability of the HypA-UreE complex. By contrast, addition of Zn(2+), but not Ni(2+), altered the kinetics and greatly increased the stability of the UreE-UreG complex, likely due in part to Zn(2+)-mediated oligomerization of UreE. Finally our results unambiguously show that HypA, UreE and UreG cannot form a heterotrimeric protein complex in vitro; instead, HypA and UreG compete with each other for UreE recognition. GENERAL SIGNIFICANCE Factors influencing the pathogen's nickel budget are important to understand pathogenesis and for future drug design.
Collapse
Affiliation(s)
- Stéphane L Benoit
- Department of Microbiology, University of Georgia, 805 Biological Sciences Bldg., Athens, GA, USA
| | | | | | | |
Collapse
|
14
|
Brown CC, Helms KA, Hill SA, Ghosh D, Salerno JC, McMurry JL. Kinetic characterization of calmodulin‐troponin C chimeras binding to endothelial and neuronal nitric oxide synthases. FASEB J 2012. [DOI: 10.1096/fasebj.26.1_supplement.984.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Katy A. Helms
- Chemistry & BiochemistryKennesaw State UniversityKennesawGA
| | | | | | | | | |
Collapse
|
15
|
Hill SA, Helms KA, Brown CC, Benoit SL, Maier RJ, McMurry JL. Kinetic characterization of binding among Helicobacter pylori nickel maturation enzyme accessory proteins. FASEB J 2012. [DOI: 10.1096/fasebj.26.1_supplement.984.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Katy A. Helms
- Chemistry & BiochemistryKennesaw State UniversityKennesawGA
| | | | | | | | | |
Collapse
|
16
|
Mays JR, Hill SA, Moyers JT, Blagg BSJ. The synthesis and evaluation of flavone and isoflavone chimeras of novobiocin and derrubone. Bioorg Med Chem 2010; 18:249-66. [PMID: 19932969 PMCID: PMC2818389 DOI: 10.1016/j.bmc.2009.10.061] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2009] [Revised: 10/28/2009] [Accepted: 10/29/2009] [Indexed: 01/07/2023]
Abstract
The natural products novobiocin and derrubone have both demonstrated Hsp90 inhibition and structure-activity relationships have been established for each scaffold. Given these compounds share several key structural features, we hypothesized that incorporation of elements from each could provide insight to structural features important for Hsp90 inhibition. Thus, chimeric analogues of novobiocin and derrubone were constructed and evaluated. These studies confirmed that the functionality present at the 3-position of the isoflavone plays a critical role in determining Hsp90 inhibition and suggests that the bicyclic ring system present in both novobiocin and derrubone do not share similar modes of binding.
Collapse
Affiliation(s)
- Jared R Mays
- Department of Medicinal Chemistry, 1251 Wescoe Hall Drive, Malott 4070, The University of Kansas, Lawrence, KS 66045-7563, United States
| | | | | | | |
Collapse
|
17
|
Tozer GM, Kanthou C, Lewis G, Prise VE, Vojnovic B, Hill SA. Tumour vascular disrupting agents: combating treatment resistance. Br J Radiol 2008; 81 Spec No 1:S12-20. [PMID: 18819993 DOI: 10.1259/bjr/36205483] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
A large group of tubulin-binding microtubule-depolymerizing agents act as tumour vascular disrupting agents (VDAs). Several members of this group are now in clinical trials in combination with conventional anticancer drugs and radiotherapy. Here we briefly update on the development of tubulin-binding combretastatins as VDAs, summarize what is known of their mechanisms of action and address issues relating to treatment resistance, using disodium combretastatin A-4 3-O-phosphate (CA-4-P) as an example. Characteristically, VDAs cause a rapid shutdown of blood flow to tumour tissue with much less effect in normal tissues. However, the tumour rim is relatively resistant to treatment. Hypoxia (or hypoxia reoxygenation) induces upregulation of genes associated with angiogenesis and drug resistance. It may be possible to take advantage of treatment-induced hypoxia by combining with drugs that are activated under hypoxic conditions. In summary, VDAs provide a novel approach to cancer treatment, which should effectively complement standard treatments, if treatment resistance is addressed by judicious combination treatment strategies.
Collapse
Affiliation(s)
- G M Tozer
- University of Sheffield, Academic Unit of Surgical Oncology, K Floor, School of Medicine & Biomedical Sciences, Beech Hill Road, Sheffield S10 2RX, UK.
| | | | | | | | | | | |
Collapse
|
18
|
Hadden MK, Hill SA, Davenport J, Matts RL, Blagg BSJ. Synthesis and evaluation of Hsp90 inhibitors that contain the 1,4-naphthoquinone scaffold. Bioorg Med Chem 2008; 17:634-40. [PMID: 19101151 DOI: 10.1016/j.bmc.2008.11.064] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [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] [Received: 10/08/2008] [Revised: 11/20/2008] [Accepted: 11/24/2008] [Indexed: 12/18/2022]
Abstract
High-throughput screening of a library of diverse molecules has identified the 1,4-naphthoquinone scaffold as a new class of Hsp90 inhibitors. The synthesis and evaluation of a rationally-designed series of analogues containing the naphthoquinone core scaffold has provided key structure-activity relationships for these compounds. The most active inhibitors exhibited potent in vitro activity with low micromolar IC(50) values in anti-proliferation and Her2 degradation assays. In addition, 3g, 12, and 13a induced the degradation of oncogenic Hsp90 client proteins, a hallmark of Hsp90 inhibition. The identification of these naphthoquinones as Hsp90 inhibitors provides a new scaffold upon which improved Hsp90 inhibitors can be developed.
Collapse
Affiliation(s)
- M Kyle Hadden
- Department of Medicinal Chemistry, The University of Kansas, 1251 Wescoe Hall Dr., Malott 4070, Lawrence, KS 66045-7563, United States
| | | | | | | | | |
Collapse
|
19
|
Dixon MH, Hill SA, Jackson MB, Ratcliffe RG, Sweetlove LJ. Physiological and metabolic adaptations of Potamogeton pectinatus L. tubers support rapid elongation of stem tissue in the absence of oxygen. Plant Cell Physiol 2006; 47:128-40. [PMID: 16284407 DOI: 10.1093/pcp/pci229] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Tubers of Potamogeton pectinatus L., an aquatic pondweed, over-winter in the anoxic sediments of rivers, lakes and marshes. Growth of the pre-formed shoot that emerges from the tuber is remarkably tolerant to anoxia, with elongation of the stem occurring faster when oxygen is absent. This response, which allows the shoot to reach oxygenated waters, occurs despite a 69-81% reduction in the rate of ATP production, and it is underpinned by several physiological and metabolic adaptations that contribute to efficient energy usage. First, extension of the pre-formed shoot is the result of cell expansion, without the accumulation of new cellular material. Secondly, after over-wintering, the tuber and pre-formed shoot have the enzymes necessary for a rapid fermentative response at the onset of growth under anoxia. Thirdly, the incorporation of [(35)S]methionine into protein is greatly reduced under anoxia. The majority of the anoxically synthesized proteins differ from those in aerobically grown tissue, implying an extensive redirection of protein synthesis under anoxia. Finally, anoxia-induced cytoplasmic acidosis is prevented to an unprecedented degree. The adaptations of this anoxia-tolerant plant tissue emphasize the importance of the mechanisms that balance ATP production and consumption in the absence of oxygen.
Collapse
Affiliation(s)
- M H Dixon
- Department of Plant Sciences, University of Oxford, UK
| | | | | | | | | |
Collapse
|
20
|
Cemazar M, Wilson I, Prise VE, Bell KM, Hill SA, Tozer GM. The endothelin B (ETB) receptor agonist IRL 1620 is highly vasoconstrictive in two syngeneic rat tumour lines: potential for selective tumour blood flow modification. Br J Cancer 2005; 93:98-106. [PMID: 15970923 PMCID: PMC2361472 DOI: 10.1038/sj.bjc.6602672] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The vascular effects of the endothelin B (ETB) receptor agonist IRL 1620 were investigated in the rat P22 carcinosarcoma and a range of normal tissues in BDIX rats. Tissue blood flow rate was calculated from measurements of tissue uptake of radiolabelled iodoantipyrine. A comparison of vascular effects in the P22 tumour and the HSN sarcoma growing in CBH/CBi rats was made using laser Doppler flowmetry, showing similar effects of IRL 1620, with red cell flux rapidly decreasing by 50–60% and then returning to control levels within approximately 30 min. This corresponded to similar levels but different spatial organisation of ETB binding sites in the two tumours, as measured by autoradiography. The decrease in tumour blood flow and an increase in vascular resistance suggest that the vascular component of ETB receptors in the P22 tumour is localised on contractile elements rather than on endothelial cells. ETA receptors were also identified. Vasoconstriction occurred uniformly throughout the P22 tumour mass, consistent with a measured homogeneous distribution of ETB receptors. IRL 1620 caused vasoconstriction in normal skeletal muscle, kidney and small intestine of the BDIX rat as well as in tumour, but did not affect blood flow in other tissues. These effects could be useful for limiting toxicity of certain chemotherapeutic agents. Fully functional ETB receptors are clearly expressed on tumour vasculature and IRL 1620 shows promise for short-term modification of tumour blood flow. Expression levels of ETB receptors on the tumour vasculature could be useful for predicting which tumours are likely to respond to IRL 1620.
Collapse
Affiliation(s)
- M Cemazar
- Gray Cancer Institute, Mount Vernon Hospital, PO Box 100, Northwood, Middlesex HA6 2JR, UK
| | - I Wilson
- Gray Cancer Institute, Mount Vernon Hospital, PO Box 100, Northwood, Middlesex HA6 2JR, UK
| | - V E Prise
- Gray Cancer Institute, Mount Vernon Hospital, PO Box 100, Northwood, Middlesex HA6 2JR, UK
| | - K M Bell
- Gray Cancer Institute, Mount Vernon Hospital, PO Box 100, Northwood, Middlesex HA6 2JR, UK
| | - S A Hill
- Gray Cancer Institute, Mount Vernon Hospital, PO Box 100, Northwood, Middlesex HA6 2JR, UK
| | - G M Tozer
- Gray Cancer Institute, Mount Vernon Hospital, PO Box 100, Northwood, Middlesex HA6 2JR, UK
- Academic Unit of Surgical Oncology, Division of Clinical Sciences, University of Sheffield, Floor K, Royal Hallamshire Hospital, Sheffield S10 2JF, UK; E-mail:
| |
Collapse
|
21
|
Overy SA, Walker HJ, Malone S, Howard TP, Baxter CJ, Sweetlove LJ, Hill SA, Quick WP. Application of metabolite profiling to the identification of traits in a population of tomato introgression lines. J Exp Bot 2005; 56:287-96. [PMID: 15596481 DOI: 10.1093/jxb/eri070] [Citation(s) in RCA: 31] [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] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Naturally occurring variation in wild species can be used to increase the genetic diversity of cultivated crops and improve agronomic value. Populations of introgression lines carrying wild species alleles afford an opportunity to identify traits associated with the introgressed regions, and facilitate characterization of the biochemistry and genetics underlying these phenotypes. Understanding plant metabolic pathways and the interactions between genes, phenotype, and environment is fundamental to functional genomics. Successful analysis of the complex network of plant metabolism requires analytical methods able to record information on as many metabolites as possible. Metabolite profiling is used to provide a snapshot of the metabolome in samples which differ in a known factor such as genetic background. Differences between the metabolite profiles can identify those metabolites/metabolic pathways affected by the introgression and allow genetic maps for metabolic alterations to be established. A Time-of-Flight Mass Spectrometry method is presented, with associated data reduction, used for profiling aqueous metabolites fom tomato. Analysis of ripe fruits of two tomato species, Lycopersicon esculentum and L. pennellii, showed differences in the amounts of many metabolites, including organic acids and sugars. Six introgression lines, L. pennellii introgressions within L. esculentum, were also examined and showed that Principal Component Analysis can reveal subtle differences in metabolism of the introgressed lines when compared to their parents.
Collapse
Affiliation(s)
- S A Overy
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK
| | | | | | | | | | | | | | | |
Collapse
|
22
|
|
23
|
Abstract
We investigated the effect of a single oral dose of the selective noradrenaline reuptake inhibitor, reboxetine (4 mg), on plasma and salivary cortisol in 24 healthy volunteers in a randomized, placebo-controlled, parallel-group design. Reboxetine significantly increased both plasma and salivary cortisol, although the correlation between the responses in plasma and saliva was modest. Our results are consistent with previous neuroendocrine challenge studies showing that potentiation of brain noradrenaline function stimulates the hypothalamic-pituitary-adrenal axis. Reboxetine-induced salivary cortisol release appears to be a simple and relatively non-invasive test of hypothalamic noradrenaline function. However, placebo-controlled, within-subject designs are likely to yield a more valid measure of noradrenaline-mediated cortisol release.
Collapse
Affiliation(s)
- S A Hill
- University Department of Psychiatry, Warneford Hospital, Oxford, UK
| | | | | | | |
Collapse
|
24
|
Hill SA, Samuels DS, Nielsen C, Knight SW, Pagotto F, Dillon JAR. Integration host factor interactions with Neisseria gene sequences: correlation between predicted binding sites and in vitro binding of Neisseria -derived IHF protein. Mol Cell Probes 2002; 16:153-8. [PMID: 12030765 DOI: 10.1006/mcpr.2001.0403] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [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: 11/22/2022]
Abstract
Putative integration host factor (IHF) binding sites are frequently being identified in Neisseria gene sequences on the basis of similarity to a degenerate Escherichia coli -derived consensus binding sequence. In this report, three different Neisseria genetic systems that contain predicted IHF binding sites were assessed for IHF binding through gel retardation analysis. The results show a positive correlation between the identification of a predicted Neisseria IHF binding site and in vitro binding of Neisseria -derived IHF protein.
Collapse
Affiliation(s)
- S A Hill
- Department of Biological Sciences, Northern Illinois University, DeKalb, IL 60115, US
| | | | | | | | | | | |
Collapse
|
25
|
Hill SA. Correct nomenclature for stereo isomers. Anaesthesia 2002; 57:200. [PMID: 11871988] [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: 02/23/2023]
|
26
|
Hill SA, Grant CCR. Recombinational error and deletion formation in Neisseria gonorrhoeae: a role for RecJ in the production of pilE (L) deletions. Mol Genet Genomics 2002; 266:962-72. [PMID: 11862490 DOI: 10.1007/s00438-001-0618-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [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: 06/29/2001] [Accepted: 11/02/2001] [Indexed: 11/26/2022]
Abstract
Genetic linkage within Neisseria gonorrhoeae populations is in equilibrium, yet the physical linkage map indicates a relatively stable chromosome structure, despite an apparently vast potential for mispairing between repeated sequences (e.g. between the multiple pil or opa alleles, or through mispairing of any of the numerous small repeated sequences that are liberally scattered throughout the chromosome). Therefore, the stability of the physical linkage map suggests that aberrant recombination between repeated sequences is a rare event. This study was undertaken to explore some of the parameters that may govern deletion events between short direct oligonucleotide repeats, using a chromosomal locus that appears to be especially prone to deletions (the pilin expression locus; pilE). In this report, we demonstrate that deletion formation at pilE occurs primarily through recombinational error following a pilE/pilS interaction; illegitimate (i.e. RecA-independent) events can occur, but they are infrequent. In contrast, when genetically engineered opa deletion substrates were constructed and placed in the chromosome, deletions at the opa loci were infrequent even under rec(+) conditions. A model is presented in which the gonococcal RecA and RecJ proteins promote pilE deletions through a recombination event that is templated or stabilised by a pilE/pilS interaction.
Collapse
Affiliation(s)
- S A Hill
- Laboratory of Biological Sciences, Northern Illinois University, DeKalb, 60115, USA.
| | | |
Collapse
|
27
|
Abstract
Thirty-four institutionalized subjects (mean age, 81 years) with a positive test for C. albicans pseudohyphae were randomly assigned to test (microwave) and control (soak) groups. All subjects received the same course of topical antifungal medication (Nystatin 300,000 IU lozenges 3x daily for 14 days). Subjects in the microwave treatment group had their maxillary denture scrubbed and then microwaved for one minute at 850 Watts. This procedure was repeated three times. For subjects receiving the standard denture soak treatment, the nursing staff was instructed to disinfect the maxillary dentures in 0.2% chlorhexidine digluconate solution overnight for 14 days, changing the solution every two days. Infestation of the tissue surface of the maxillary denture with C. albicans progressively took place over the three-month period following treatment such that 8 (53%) of the microwaved dentures and 16 (84%) of the soaked dentures demonstrated pseudohyphae as determined by Gram stain. Infection of the soft tissues with the hyphal form of C. albicans also increased with time. After three months, one (8%) patient in the microwave group and 12 (63%) patients in the denture soak group demonstrated pseudohyphae on the cytological smears. Re-infestation of the denture surface and infection of the adjacent soft tissue were delayed dramatically in patients whose dentures were microwaved compared with those whose dentures were disinfected by being soaked in a chlorhexidine solution. However, microwave treatment is not recommended for all dentures and should be used with caution.
Collapse
Affiliation(s)
- D W Banting
- Division of Community Dentistry, Faculty of Medicine & Dentistry, The University of Western Ontario, London, Canada.
| | | |
Collapse
|
28
|
Abstract
The requirement for tumour vascularisation to permit the expansion of solid tumours beyond a threshold size of approximately 1 mm diameter has focussed attention on anti-vascular and anti-angiogenic agents for cancer therapy. Combretastatin-A4 (cis CA-4P) is a tubulin-binding agent that is cytotoxic for proliferating endothelial cells in vitro and causes anti-vascular effects in the established tumour vessels of some primary tumours. Preliminary data from Phase I clinical trials indicate that cis CA-4 may also be effective in targeting the vasculature of human tumours. As metastatic disease is the principal cause of mortality in cancer, we have investigated the effects of cis CA-4 on metastatic development using an in vivo model. We show that bolus or continuous administration of cis CA-4P results in potent inhibition of metastases derived from ectopic primary Lewis lung carcinomas in mice whereas the trans CA-4 isomer is without effect. These data further characterise the activity of CA-4 in vivo and suggest that the drug should be evaluated clinically as an anti-metastatic agent.
Collapse
Affiliation(s)
- J Griggs
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK
| | | | | | | | | | | | | |
Collapse
|
29
|
Beauregard DA, Hill SA, Chaplin DJ, Brindle KM. The susceptibility of tumors to the antivascular drug combretastatin A4 phosphate correlates with vascular permeability. Cancer Res 2001; 61:6811-5. [PMID: 11559555] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
The acute effects of the antivascular drug, combretastatin A4 phosphate, on tumor energy status and perfusion were assessed using magnetic resonance imaging (MRI) and spectroscopy. Localized (31)P magnetic resonance spectroscopy showed that LoVo and RIF-1 tumors responded well to drug treatment, with significant increases in the P(i)/nucleoside triphosphate ratio within 3 h, whereas SaS, SaF, and HT29 tumors did not respond to the same extent. This variable response was also seen in MRI experiments in which tumor perfusion was assessed by monitoring the kinetics of inflow of the contrast agent, gadolinium diethylenetriaminepentaacetate. These data were analyzed to give the initial rate and time constant for inflow of contrast agent and the integral under the inflow curve. The differential susceptibility of the tumors to combretastatin A4 phosphate showed a positive correlation with prior MRI measurements of tumor vascular permeability, which was determined by measuring the inflow of a macromolecular contrast agent, BSA-gadolinium diethylenetriaminepentaacetate.
Collapse
Affiliation(s)
- D A Beauregard
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom
| | | | | | | |
Collapse
|
30
|
Derse D, Hill SA, Lloyd PA, Morse BA. Examining human T-lymphotropic virus type 1 infection and replication by cell-free infection with recombinant virus vectors. J Virol 2001; 75:8461-8. [PMID: 11507191 PMCID: PMC115091 DOI: 10.1128/jvi.75.18.8461-8468.2001] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.0] [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: 11/20/2022] Open
Abstract
A sensitive and quantitative cell-free infection assay, utilizing recombinant human T-cell leukemia virus type 1 (HTLV-1)-based vectors, was developed in order to analyze early events in the virus replication cycle. Previous difficulties with the low infectivity and restricted expression of the virus have prevented a clear understanding of these events. Virus stocks were generated by transfecting cells with three plasmids: (i) a packaging plasmid encoding HTLV-1 structural and regulatory proteins, (ii) an HTLV-1 transfer vector containing either firefly luciferase or enhanced yellow fluorescent protein genes, and (iii) an envelope expression plasmid. Single-round infections were initiated by exposing target cells to filtered supernatants and quantified by assaying for luciferase activity in cell extracts or by enumerating transduced cells by flow cytometry. Transduction was dependent on reverse transcription and integration of the recombinant virus genome, as shown by the effects of the reverse transcriptase inhibitor 3'-azido-3'-deoxythymidine (AZT) and by mutation of the integrase gene in the packaging vector, respectively. The 50% inhibitory concentration of AZT was determined to be 30 nM in this HTLV-1 replication system. The stability of HTLV-1 particles, pseudotyped with either vesicular stomatitis virus G protein or HTLV-1 envelope, was typical of retroviruses, exhibiting a half-life of approximately 3.5 h at 37 degrees C. The specific infectivity of recombinant HTLV-1 virions was at least 3 orders of magnitude lower than that of analogous HIV-1 particles, though both were pseudotyped with the same envelope. Thus, the low infectivity of HTLV-1 is determined in large part by properties of the core particle and by the efficiency of postentry processes.
Collapse
Affiliation(s)
- D Derse
- Basic Research Laboratory, National Cancer Institute, NCI-Frederick, Frederick, Maryland 21702, USA.
| | | | | | | |
Collapse
|
31
|
Jenner HL, Winning BM, Millar AH, Tomlinson KL, Leaver CJ, Hill SA. NAD malic enzyme and the control of carbohydrate metabolism in potato tubers. Plant Physiol 2001; 126:1139-49. [PMID: 11457964 PMCID: PMC116470 DOI: 10.1104/pp.126.3.1139] [Citation(s) in RCA: 83] [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: 11/17/2000] [Revised: 01/15/2001] [Accepted: 02/27/2001] [Indexed: 05/18/2023]
Abstract
Potato (Solanum tuberosum) plants were transformed with a cDNA encoding the 59-kD subunit of the potato tuber NAD-dependent malic enzyme (NADME) in the antisense orientation. Measurements of the maximum catalytic activity of NADME in tubers revealed a range of reductions in the activity of this enzyme down to 40% of wild-type activity. There were no detrimental effects on plant growth or tuber yield. Biochemical analyses of developing tubers indicated that a reduction in NADME activity had no detectable effects on flux through the tricarboxylic acid cycle. However, there was an effect on glycolytic metabolism with significant increases in the concentration of 3-phosphoglycerate and phosphoenolpyruvate. These results suggest that alterations in the levels of intermediates toward the end of the glycolytic pathway may allow respiratory flux to continue at wild-type rates despite the reduction in NADME. There was also a statistically significant negative correlation between NADME activity and tuber starch content, with tubers containing reduced NADME having an increased starch content. The effect on plastid metabolism may result from the observed glycolytic perturbations.
Collapse
Affiliation(s)
- H L Jenner
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, United Kingdom
| | | | | | | | | | | |
Collapse
|
32
|
Sweetlove LJ, Kruger NJ, Hill SA. Starch synthesis in transgenic potato tubers with increased 3-phosphoglyceric acid content as a consequence of increased 6-phosphofructokinase activity. Planta 2001; 213:478-482. [PMID: 11506372 DOI: 10.1007/s004250100544] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The aim of this work was to test the hypothesis that changes in cytosolic 3-phosphoglyceric acid (3-PGA) content can regulate the rate of starch synthesis in potato (Solanum tuberosum L.) tubers. The amount of 3-PGA was increased by expressing bacterial phosphofructokinase (PFK; EC 2.7.1.11) in transgenic potato tubers. The resultant 3-fold increase in PFK activity was accompanied by an increase in metabolites downstream of PFK, including a 3-fold increase in 3-PGA. There was also a decrease in metabolites upstream of PFK, most notably of glucose-6-phosphate. The increase in 3-PGA did not affect the amount of starch that accumulated in developing tubers, nor its rate of synthesis in tuber discs cut from developing tubers. This suggests that changes in cytosolic 3-PGA may not affect the rate of starch synthesis under all circumstances. We propose that in this case, a decrease in glucose-6-phosphate (which is transported into the amyloplast as a substrate for starch synthesis) may be sufficient to counteract the effect of increased 3-PGA.
Collapse
Affiliation(s)
- L J Sweetlove
- Department of Plant Sciences, University of Oxford, UK.
| | | | | |
Collapse
|
33
|
Pedley RB, Hill SA, Boxer GM, Flynn AA, Boden R, Watson R, Dearling J, Chaplin DJ, Begent RH. Eradication of colorectal xenografts by combined radioimmunotherapy and combretastatin a-4 3-O-phosphate. Cancer Res 2001; 61:4716-22. [PMID: 11406542] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
Solid tumors have a heterogeneous pathophysiology, which has a major impact on therapy. Using SW1222 colorectal xenografts grown in nude mice, we have shown that antibody-targeted radioimmunotherapy (RIT) effectively treated the well-perfused tumor rim, producing regressions for approximately 35 days, but was less effective at the more hypoxic center. By 72 h after RIT, the number of apoptotic cells rose from an overall value of 1% in untreated tumors to 35% at the tumor periphery and 10% at the center. The antivascular agent disodium combretastatin A-4 3-O-phosphate (CA4-P) rapidly reduced tumor blood flow to 62% of control values by 1 h, 23% by 3 h, and between 32-36% from 6 to 24 h after administration. This created central hemorrhagic necrosis, but a peripheral rim of cells continued to grow, and survival was unaffected. Changes in the pattern of perfusion across the tumor over time were zonal. Untreated mice showed perfusion throughout the tumor, with greatest activity at the rim. There was an overall reduction at 1 h, and total cessation of central perfusion from 3 h onward. A narrow peripheral rim of perfusion was always present, which increased in intensity and extent between 6 and 24 h, either through reperfusion or new vessel growth. Combining these two complementary therapies (7.4 MBq (131)I-labeled anti-carcinoembryonic antigen IgG i.v. plus a single 200 mg/kg dose of CA4-P i.p.) produced complete cures in five of six mice for >9 months. Allowing maximal tumor localization of antibody (48 h) before blood flow inhibition by CA4-P increased tumor retention by two to three times control levels by 96 h without altering normal tissue levels, as confirmed by gamma counting and phosphor image analysis. The success of this combined, synergistic therapy was probably the result of several factors: (a) the killing of tumor cells in the outer, radiosensitive region by targeted radiotherapy; (b) enhancement of RIT by entrapment of additional radioantibody after combretastatin-induced vessel collapse; and (c) destruction of the central, more hypoxic and radioresistant region by CA4-P. This work demonstrates the need to consider cancer treatment in a biologically heterogeneous setting, if results are to be effectively translated to the clinic.
Collapse
Affiliation(s)
- R B Pedley
- Department of Oncology, Royal Free and University College Medical School, Royal Free Campus, London NW3 2PF, United Kingdom
| | | | | | | | | | | | | | | | | |
Collapse
|
34
|
Abstract
Tracheal agenesis (TA) is a rare congenital anomaly that typically has fatal consequences. Its rarity, lack of prenatal symptoms, and emergent presentation usually lead to a failure to arrive at the correct diagnosis and manage the airway properly before the onset of irreversible cerebral anoxia. We report the case history of an infant born with immediate respiratory failure who was diagnosed with tracheal agenesis. The clinical features, embryology, classification schemes and surgical management are discussed with the hope that increased awareness and earlier diagnosis may lead to better chances of survival for affected individuals.
Collapse
Affiliation(s)
- S A Hill
- University of Kentucky Chandler Medical Center, 800 Rose Street, Lexington, KY 40515, USA
| | | | | |
Collapse
|
35
|
Duncan MJ, Herron JM, Hill SA. Aging selectively suppresses vasoactive intestinal peptide messenger RNA expression in the suprachiasmatic nucleus of the Syrian hamster. Brain Res Mol Brain Res 2001; 87:196-203. [PMID: 11245922 DOI: 10.1016/s0169-328x(01)00015-8] [Citation(s) in RCA: 55] [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] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Aging leads to many changes in the expression of circadian rhythms, including reduced amplitude, altered relationship to the environmental illumination cycle, and reduced sensitivity to phase resetting signals. Neuropeptide synthesizing neurons in the suprachiasmatic nucleus (SCN), the principal circadian pacemaker in mammals, play a role in regulating pacemaker function and in coupling the pacemaker to overt circadian rhythms. Aging may alter the activity of neuropeptide neurons in the SCN, which could be reflected in changes in mRNA expression. Therefore, this study investigated whether aging alters the level or rhythm of expression of neuropeptide mRNAs in the SCN of male Syrian hamsters, a well established model for the study of age-related changes in circadian rhythms. Three age groups of hamsters (young [3--5 months old], middle-aged [12--15 months old] and old [19--22 months old] were sacrificed at five times of day. Their brains were dissected and sections through the suprachiasmatic nucleus were prepared and used for in situ hybridization for mRNAs for vasoactive intestinal peptide (VIP), arginine vasopressin (AVP) and somatostatin (SS). Aging selectively decreased the SCN expression of VIP mRNA without affecting AVP mRNA or SS mRNA. Also, only AVP mRNA expression exhibited a robust 24-h rhythm, in contrast to previous findings in other species that VIP mRNA and SS mRNA, as well as AVP mRNA, exhibit 24-h rhythms in the SCN. The present findings suggest that age-related reductions in VIP mRNA expression may contribute to the alterations in entrainment and attenuated sensitivity to phase resetting signals that are characteristic of aging. Furthermore, the results demonstrate that neuropeptide gene expression in the SCN is differentially regulated by aging and varies among species.
Collapse
Affiliation(s)
- M J Duncan
- Department of Anatomy and Neurobiology, University of Kentucky Medical Center, 800 Rose Street, Lexington, KY 40536-0298, USA.
| | | | | |
Collapse
|
36
|
Hill SA, Mazenko GF. Nonlinear hydrodynamical approach to granular materials. Phys Rev E Stat Nonlin Soft Matter Phys 2001; 63:031303. [PMID: 11308645 DOI: 10.1103/physreve.63.031303] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2000] [Indexed: 05/23/2023]
Abstract
We propose a nonlinear hydrodynamical model of granular materials. We show how this model describes the formation of a sandpile from a homogeneous distribution of material under gravity, and then discuss a simulation of a rotating sandpile which shows, in qualitative agreement with experiment, a static and dynamic angle of repose.
Collapse
Affiliation(s)
- S A Hill
- James Franck Institute and Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
| | | |
Collapse
|
37
|
Abstract
Macrophages can account for up to 50% of tumour mass and secrete many angiogenic factors. Furthermore, tumour hypoxia is thought to play a major role in the activation of macrophages and the regulation of angiogenesis. In this paper, we demonstrate a strong correlation between hypoxia and the recruitment of immune cells binding to IgG in 8 experimental tumours. We provide evidence that IgG binding immune cells in 3 tumour lines are predominately composed of macrophages. Reduced oxygenation may act as a stimulus for recruitment of immune cells to the tumour mass, and the detection of either IgG-positive host cells or macrophages may offer an alternative method for monitoring tumour hypoxia.
Collapse
Affiliation(s)
- D R Collingridge
- PET Oncology Group, Imperial College School of Medicine, Hammersmith Hospital, MRC Cyclotron Building, Du Cane Road, London, W12 0NN, UK
| | | | | |
Collapse
|
38
|
Abstract
Health policy in the United States has changed dramatically over the past three decades, with the main concern shifting from expanded health care coverage to containment of health care costs. The current focus on providing cost-effective health services, reflected in the growth of managed care initiatives, has elevated concern about the quality of health care. The authors contend that quality of health care has always been the key focus in the women's health movement, which evolved in the late 1960s as the first significant challenge to modern medicine. In this article, they apply the analytic lens of gender to develop a fresh perspective on U.S. health care organizations and policies, examining the six broad demands of the feminist consumer model of health care, all of which hinge on the issue of quality care for women, to determine whether women's health needs are now being better addressed. The authors conclude that, despite some notable gains in the roles of women as consumers and providers of health care, many of the new health reforms have replicated and solidified the historical inequities in the health care system.
Collapse
Affiliation(s)
- M K Zimmerman
- Department of Health Policy and Management, University of Kansas, 12600 Quivira Road, Overland Park, KS 66213, USA
| | | |
Collapse
|
39
|
Logan DC, Millar AH, Sweetlove LJ, Hill SA, Leaver CJ. Mitochondrial biogenesis during germination in maize embryos. Plant Physiol 2001; 125:662-72. [PMID: 11161024 PMCID: PMC64868 DOI: 10.1104/pp.125.2.662] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2000] [Revised: 08/24/2000] [Accepted: 09/22/2000] [Indexed: 05/18/2023]
Abstract
Mitochondrial biogenesis and metabolism were investigated during maize (Zea mays) seed germination. Mitochondria from dry and imbibed seed exhibited NADH-dependent O(2) uptake that was completely inhibited by KCN and antimycin A. Mitochondria in the dry seed had a lower rate of succinate-dependent O(2) uptake relative to that measured in imbibed and germinated seed. The activities of the tricarboxylic acid (TCA) cycle enzymes, pyruvate dehydrogenase complex, 2-oxoglutarate dehydrogenase complex, NAD-malic enzyme, and citrate synthase, are similarly low in mitochondria from dry seed and this correlates with a lower relative abundance of the mitochondrial matrix-located citrate synthase and pyruvate dehydrogenase complex E1alpha-subunit polypeptides. Electron microscopy revealed that mitochondria in the dry seed have a poorly developed internal membrane structure with few cristae; following 24 h of germination the mitochondria developed a more normal structure with more developed cristae. The mitochondria from maize embryos could be fractionated into two subpopulations by Suc density gradient centrifugation: one subpopulation of buoyant density equivalent to 22% to 28% (w/w) Suc; the other equivalent to 37% to 42% (w/w) Suc. These two subpopulations had different activities of specific mitochondrial enzymes and contained different amounts of specific mitochondrial proteins as revealed by western-blot analysis. Both subpopulations from the dry embryo were comprised of poorly developed mitochondria. However, during imbibition mitochondria in the heavy fraction (37%-42% [w/w] Suc) progressively acquired characteristics of fully functional mitochondria found in the germinated seedling in terms of structure, enzymic activity, and protein complement. In contrast, mitochondria in the light fraction (22% to 28% [w/w] Suc) show no significant structural change during imbibition and the amounts of specific mitochondrial proteins decreased significantly during germination.
Collapse
Affiliation(s)
- D C Logan
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, United Kingdom.
| | | | | | | | | |
Collapse
|
40
|
Abstract
Two human models were developed to quantify the stratum corneum removed by different adhesive dressings and to measure the peel force of dressing removal and relate this to stratum corneum removal. The first was an open study designed to compare the effects of applying Mepiform Safetac, Tielle and Duoderm Extra Thin to the skin of 12 normal volunteers aged 19-53 years. Treatments were applied once (one 24-hour application) or three times (three x 24-hour applications) to forearm skin which had been prestained with methylene blue. After dressing removal the dye left on the skin was sampled using the skin surface biopsy method and measured spectrophotometrically. The results show that, after one and three applications, the Mepiform Safetac sites had a higher level of dye than those on which the other dressings had been applied (p < 0.05, after three applications). Based on the assumption that the more dye is left on the skin, the less damage is caused, this suggests that Mepiform Safetac is less damaging to the skin surface than the other products tested. In the second study the peel force needed to remove adhesive dressings from prestained skin was measured and related to the amount of stratum corneum removed. Mepilex Border Safetac, Duoderm Extra Thin, Allevyn Adhesive, Biatain Adhesive and Tielle Hydropolymer Dressing were compared in 20 normal volunteers aged 23-64 years. Three consecutive 24-hour applications of each product were made, with measurements of peel force at 24, 48 and 72 hours. The amount of dye remaining on the skin at 72 hours was assessed by the surface biopsy method. Statistically significant differences between products were observed in terms of both peak force and steady state force of removal. Differences in the level of damage to the superficial stratum corneum were also detected. However, low levels of peel force were not always associated with low damage and, therefore, other factors must contribute to stratum corneum removal in this model.
Collapse
Affiliation(s)
- P J Dykes
- Department of Dermatology, University of Wales College of Medicine, Cardiff, UK
| | | | | |
Collapse
|
41
|
Abstract
OBJECTIVE To determine whether age-related mitochondrial DNA mutations occur in the human larynx. STUDY DESIGN Genetic study of cadaveric larynx specimens. METHODS Vocal fold mucosa, thyroarytenoid muscle, and cricoarytenoidjoint tissue were harvested from 13 fresh postmortem larynges (age range, 2 d-82 y). DNA was extracted from each sample, and the polymerase chain reaction (PCR) was used to amplify a target DNA sequence resulting from the common age-associated, 4977-base-pair (bp) mitochondrial DNA deletion. PCR products were visualized by agarose gel electrophoresis. Automated sequencing determined the sequence of identified PCR products. SUBJECTS Thirteen cadaveric larynges were obtained through the University of Kentucky Medical Center (Lexington, KY). Specimens from patients with a history of head and neck cancer, previous laryngeal trauma, or surgery were excluded. RESULTS Strongly positive bands were identified in samples from three individuals. Weaker bands were seen in samples from four other samples. No band was noted from the two pediatric larynges. Different band patterns were seen among the three different tissue sites in the larynges with positive PCR products, but no consistent pattern was seen. Sequencing of the identified PCR products from selected samples confirmed that they were products of the age-associated, 4977-bp mitochondrial DNA deletion. CONCLUSIONS An age-associated mitochondrial DNA deletion was detected in several post-mortem human larynges. Its presence seemed to increase in appearance with age. In the larynges in which the deletion occurred, there were individual regional differences in the occurrence of the deletion, but no consistent pattern was noted across all individuals who carried the deletion.
Collapse
Affiliation(s)
- J M Manaligod
- Division of Otolaryngology--Head and Neck Surgery, University of Kentucky Medical Center, Lexington 40536, USA
| | | | | | | | | | | |
Collapse
|
42
|
Hill SA. Neisseria gonorrhoeae recJ mutants show defects in recombinational repair of alkylated bases and UV-induced pyrimidine dimers. Mol Gen Genet 2000; 264:268-75. [PMID: 11085266 DOI: 10.1007/s004380000316] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Neisseria gonorrhoeae lacks several common DNA repair pathways found in other organisms. As recent evidence had indicated that gonococci use recombinational repair to repair UV-induced DNA lesions, this study examined whether the gonococcal RecJ homologue contributes in this repair capacity. The recJ gene from strain MS11 was cloned and sequenced and was found to show a considerable degree of identity to its Escherichia coli homologue. A N. gonorrhoeae delta recJ mutant was constructed and tested for recombinational proficiency as well as for defects in DNA repair. In the absence of the RecJ exonuclease, DNA transformation and pilin switching occurred at wild type levels, indicating that the efficiency of recombination remained unimpaired. In contrast, N. gonorrhoeae delta recJ mutants showed extreme sensitivity to low levels of UV irradiation and to exposure to DNA-alkylating reagents [e.g. ethyl methanesulfonate (EMS) and methyl methanesulfonate (MMS)]. Complementation of the gonococcal recJ mutant in cis restored resistance to low-level UV, indicating that the gonococcal RecJ protein is involved in recombinational repair, and can act independently of other single-strand-specific exonucleases. Furthermore, transformation competence was not required for RecJ-dependent DNA repair. Overall, the data show that N. gonorrhoeae recJ mutants present a unique phenotype when compared to their E. coli recJ counterparts, and further support the contention that RecORJ-dependent recombinational repair is a major DNA repair pathway in the genus Neisseria.
Collapse
Affiliation(s)
- S A Hill
- Department of Biological Sciences, Northern Illinois University, DeKalb 60115, USA.
| |
Collapse
|
43
|
Abstract
The anti-vascular action of the tubulin binding agent combretastatin A-4 phosphate (CA-4-P) has been quantified in two types of murine tumour, the breast adenocarcinoma CaNT and the round cell sarcoma SaS. The functional vascular volume, assessed using a fluorescent carbocyanine dye, was significantly reduced at 18 h after CA-4-P treatment in both tumour types, although the degree of reduction was very different in the two tumours. The SaS tumour, which has a higher nitric oxide synthase (NOS) activity than the CaNT tumour, showed approximately 10-fold greater resistance to vascular damage by CA-4-P. This is consistent with our previous findings, which showed that NO exerts a protective action against this drug. Simultaneous administration of CA-4-P with a NOS inhibitor, N(omega)-nitro-L-arginine (L-NNA), resulted in enhanced vascular damage and cytotoxicity in both tumour types. Administration of diethylamine NO, an NO donor, conferred protection against the vascular damaging effects. Following treatment with CA-4-P, neutrophil infiltration into the tumours, measured by myeloperoxidase (MPO) activity, was significantly increased. Levels of MPO activity also correlated with the levels of vascular injury and cytotoxicity measured in both tumour types. Neutrophilic MPO generates free radicals and may therefore contribute to the vascular damage associated with CA-4-P treatment. MPO activity was significantly increased in the presence of L-NNA, suggesting that the protective effect of NO against CA-4-P-induced vascular injury may be, at least partially, mediated by limiting neutrophil infiltration. The data are consistent with the hypothesis that neutrophil action contributes to vascular injury by CA-4-P and that NO generation acts to protect the tumour vasculature against CA4-P-induced injury. The protective effect of NO is probably associated with an anti-neutrophil action.
Collapse
Affiliation(s)
- C S Parkins
- Tumour Microcirculation Group, Gray Laboratory Cancer Research Trust, Mount Vernon Hospital, Northwood, Middlesex, HA6 2JR, UK
| | | | | | | | | |
Collapse
|
44
|
Kenny JJ, Derby EG, Yoder JA, Hill SA, Fischer RT, Tucker PW, Claflin JL, Longo DL. Positive and negative selection of antigen-specific B cells in transgenic mice expressing variant forms of the V(H)1 (T15) heavy chain. Int Immunol 2000; 12:873-85. [PMID: 10837415 DOI: 10.1093/intimm/12.6.873] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [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: 11/14/2022] Open
Abstract
Four variant forms of the V1 (T15-H chain) gene are synthesized in mice. Each V1 variant pairs with a distinct L chain to produce a binding site having specificity for phosphocholine (PC). Transgenic mice expressing variant forms of the V1 gene were analyzed to elucidate the factors driving B cell selection into the peripheral repertoire. In all four lines of H chain transgenic mice analyzed, transgene expression caused complete allelic exclusion of endogenous H chains in the bone marrow (BM), whereas most splenic B cells expressed endogenous H chains. The number of sIgM(+) BM B cells and their sIg receptor number was reduced compared to that of normal transgene-negative controls, suggesting that B cells expressing transgene-encoded H chains were being negatively selected in the BM. Mice expressing autoreactive forms of the V1 transgene with lower affinity for PC (M603H and M167H) exhibit positive selection of PC-specific B cells into the spleen, whereas mice expressing the higher affinity T15H variant exhibited elevated PC-specific B cells in the peritoneal cavity but few V(H)1(+) splenic B cells. These data suggest that the higher affinity T15-id(+) B cells preferentially survive in the peritoneal cavity. When these H chain transgenes were crossed into the mu MT knockout mouse in which surface expression of endogenous H chains is blocked, the percent of splenic V(H)1(+) PC-specific B cells increased up to 5-fold and T15-id(+) B cells were detectable in the spleen of T15H mice. This implies that T15-id(+) PC-specific B cells can be selected into the periphery, but they compete poorly with follicular B cells expressing endogenous Ig.
Collapse
Affiliation(s)
- J J Kenny
- National Institutes of Health, National Institute on Aging, Gerontology Research Center, 5600 Nathan Shock Drive, Baltimore, MD 21224, USA
| | | | | | | | | | | | | | | |
Collapse
|
45
|
Abstract
The selection of which high-pass filter cutoff to use in P300 studies continues to be a serious methodological consideration. To determine whether there was an optimal range of bandpass widths-a range in which P300 voltage and latency would not show statistically significant differences-the authors recorded P300 responses to the auditory "oddball" paradigm from Cz and Pz electrodes in a group of eight healthy males. The authors used high-pass filter cutoffs of 0.01, 0.1, 0.3, and 1.0 Hz with low-pass filter cutoffs of 30 and 100 Hz and measured both P300 peak voltages and P300 integrated mean voltages at 12 bandpass settings. There were statistically significant differences in 7 out of 12 bandpass comparisons for P300 peak voltages and in 7 out of 12 bandwidth comparisons for P300 integrated mean voltages. For P300 latencies, there were statistically significant differences in 9 out of 12 bandwidth comparisons. Based on these results, the best recommendation, therefore, is that the high-pass filter be set no higher than 0.3 Hz.
Collapse
Affiliation(s)
- D P Holinger
- Department of Psychiatry, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02215, USA
| | | | | | | | | | | |
Collapse
|
46
|
Hill SA. The man who claimed to be a paedophile. J Med Ethics 2000; 26:137-138. [PMID: 10786326 PMCID: PMC1733194 DOI: 10.1136/jme.26.2.137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A psychiatrist recounts a case of a man presenting with severe depression who claimed to have abused children and his pet dog. Clinical management of the case hinged on whether this claim was true, a lie or delusional. The uncertainty over this raised complex ethical dilemmas regarding confidentiality and protection of the public (and animals).
Collapse
|
47
|
Wiebe JP, Muzia D, Hu J, Szwajcer D, Hill SA, Seachrist JL. The 4-pregnene and 5alpha-pregnane progesterone metabolites formed in nontumorous and tumorous breast tissue have opposite effects on breast cell proliferation and adhesion. Cancer Res 2000; 60:936-43. [PMID: 10706108] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
Progesterone is required for the full proliferative activity of the breasts and may be directly or indirectly involved in either stimulating or inhibiting breast cancer. To determine whether the effects on breast cancer are attributable to progesterone metabolites, we compared the capacity of nontumorous and tumorous breast tissue to convert progesterone and then tested the effects of these metabolites on breast cell proliferation and anchorage. Tissues from the operated breasts of six patients with infiltrating duct carcinomas were incubated with [14C]progesterone for 2, 4, and 8 h, and the metabolites were identified and quantified. The identified metabolites (equal to >95% of recovered radioactivity) can be divided into those that retain the double bond of progesterone in the carbon-4 position of ring A (4-pregnenes) and those that are 5alpha-reduced (5alpha-pregnanes). The results show that tumorous breast tissue has elevated 5alpha-reductase activity, which results in significantly higher total levels of 5alpha-pregnanes, especially 5alpha-pregnane-3,20-dione (5alphaP), whereas normal (nontumorous) breast tissue produces more 4-pregnenes, especially 3alpha-hydroxy-4-pregnen-20-one (3alphaHP). 5alphaP and 3alphaHP are each one enzymatic step removed from progesterone, resulting from the action of either 5alpha-reductase or 3alpha-hydroxysteroid oxidoreductase (3alpha-HSO), respectively. The ratio of 5alpha-pregnanes:4-pregnenes is >5-fold greater and the ratio of 5alphaP:3alphaHP is nearly 30-fold greater in tumorous than nontumorous breast tissue incubates. In vitro studies with three breast cell lines (MCF-7, MCF-10A, and ZR-75-1) show that 3alphaHP dose dependently inhibits, whereas 5alphaP significantly stimulates, proliferation. Additional studies with MCF-7 and MCF-10A cells indicate that each of the 4-pregnenes isolated from breast tissue suppresses, whereas each respective 5alpha-reduced product stimulates, cell proliferation. Studies of cell anchorage were conducted using MCF-7 cells and various concentrations of 5alphaP or 3alphaHP. The number of cells attached to the substrate was significantly (P<0.05) decreased by treatment with > or =30 nM 5alphaP and increased by treatment with > or =50 nM 3alphaHP. Conversely, the number of cells detached from the substrate after partial trypsin exposure was significantly increased by treatment with > or =40 nM 5alphaP and decreased by treatment with > or =30 nM 3alphaHP. The results suggest that a change in in situ progesterone metabolism, resulting in an increased 5alpha-pregnane:4-pregnene (especially 5alphaP:3alphaHP) ratio, may promote breast cancer by promoting increased cell proliferation and detachment, whereas increases in 4-pregnenes may retard these tumorigenic processes. These studies suggest that endogenous progesterone metabolites may provide a new hormonal basis for breast cancer.
Collapse
Affiliation(s)
- J P Wiebe
- Hormonal Regulatory Mechanisms Laboratory, University of Western Ontario, London, Canada.
| | | | | | | | | | | |
Collapse
|
48
|
Onuska KD, Hill SA. Effect of rheumatoid factor on cardiac troponin I measurement using two commercial measurement systems. Clin Chem 2000; 46:307-8. [PMID: 10657400] [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: 02/15/2023]
|
49
|
Abstract
Neisseria gonorrhoeae is naturally competent for DNA transformation. Under most conditions encountered in vivo, gonococci express one or more opacity (Opa) proteins on their surfaces. Recently, it was shown that DNA preferentially binds to the surfaces of Opa-expressing organisms compared to those of isogenic Opa-negative strains, presumably due to the numerous cationic residues in the predicted surface-exposed loops of the Opa protein. This study examined whether Opa-DNA interactions actually influence DNA transformation of the gonococcus. The data show that Opa-expressing gonococci are more efficient recipients of DNA for transformation and are more susceptible to exogenous DNase I treatment at early stages during the DNA transformation process than non-Opa expressors. Furthermore, inhibition of the transformation process was demonstrable for Opa(+) populations when either nonspecific DNA or the polyanion heparin was used. Overall, the data suggest that Opa expression, with its presumptive positive surface charge contribution, promotes DNA transformation by causing a more prolonged sequestration of donor DNA at the cell surface, which translates into more efficient transformation over time.
Collapse
Affiliation(s)
- S A Hill
- Laboratory of Microbial Structure and Function, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana 59840, USA.
| |
Collapse
|
50
|
Abstract
The neisseriae are naturally competent for DNA transformation. This genetic study examines whether the modification status of chromosomal donor DNA affects transformation of Neisseria gonorrhoeae to drug resistance. When a single modification system was inactivated, unmodified chromosomal donor DNA was not restricted when used to transform the cognate restriction+ host, irrespective of whether the donor DNA carried a point mutation (homologous marker) or a drug-resistance gene cassette (non-homologous marker). These observations contrasted transformations performed with unmodified plasmid donor DNAs, where the incoming DNA was excluded. However, during the study, it became apparent that certain strains of gonococci showed differential incorporation of non-homologous markers when compared with the incorporation of the homologous marker, even when the donor DNAs were prepared from parental strains. Differential incorporation of markers could be rescued either through cell to cell transmission of donor DNA, or by performing in vitro transformations with donor DNA preparations that were obtained from spent culture supernatants. Overall, the data indicate that, in addition to the exclusion of foreign DNA through the requirement for a genus-specific uptake sequence, gonococci appear capable of excluding DNA on the basis of homology.
Collapse
Affiliation(s)
- S A Hill
- Department of Biological Sciences, Northern Illinois University, DeKalb, IL, USA.
| |
Collapse
|