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Terstappen LW, Buescher S, Nguyen M, Reading C. Differentiation and maturation of growth factor expanded human hematopoietic progenitors assessed by multidimensional flow cytometry. Leukemia 1992; 6:1001-10. [PMID: 1405753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Non-adherent cord blood and bone marrow mononuclear cells were analyzed by multiparameter flow cytometry before and at day 2, 4, 7, and 11 of culture in recombinant interleukin 3 (IL-3) and granulocyte colony-stimulating factor (G-CSF, cord blood) or stem cell factor (SCF), IL3 and granulocyte-macrophage colony-stimulating factor (GM-CSF, BM) to assess the differentiation and maturational pathway of myeloid cells. Before cell culture cord blood contained progenitor cells (CD34+) in various differentiation stages (CD38(-)----CD38bright), mature lymphocytes, monocytes, and neutrophils, but no immature neutrophils and immature monocytes. During cell culture, all CD34+ cells acquired the CD38 antigen between day 2 and 5 of cell culture, the CD34 antigen was lost between day 5 and 11 of cell culture. Differentiation of cells into the myeloid cell lineage was characterized by the acquisition of both CD33 and CD71. The latter is indicative for the active proliferation of these cells. Maturation of the cells into the neutrophilic pathway was indicated by the acquisition of first the CD15 antigen followed by CD11b and CD16 respectively. Whereas maturation of the cells into the monocytic pathway was indicated by the acquisition of first CD11b followed by CD14 and a dim expression of both CD15 and CD16. In normal bone marrow, cells of various maturational stages are already present before cell culture. During cell culture differentiation of cells into the myeloid lineage and maturation of the cells along the monocyte and neutrophilic lineage followed identical pathways as was observed before cell culture. Differentiation and maturational pathways of cord blood and adult bone marrow were identical. The results confirm the surface-antigen-defined pathways of myeloid cell differentiation described previously for non-cultured normal bone marrow aspirates. The detailed assessment of cell maturation and differentiation of cultured cells by multidimensional flow cytometry permits the determination of the specific effects of various recombinant human growth factors on myeloid cells.
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Claxton D, Deisseroth A, Talpaz M, Reading C, Kantarjian H, Trujillo J, Stass S, Gooch G, Spitzer G. Polyclonal hematopoiesis in interferon-induced cytogenetic remissions of chronic myelogenous leukemia. Blood 1992; 79:997-1002. [PMID: 1371081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/25/2023] Open
Abstract
Interferon (IFN) therapy of early chronic myelogenous leukemia (CML) frequently produces partial or complete cytogenetic remission of the disease. Patients with complete cytogenetic remission often continue on therapy for several years with bone marrow showing only diploid (normal) metaphases. We studied hematopoiesis in five female patients with major cytogenetic remissions from CML during IFN therapy. Clonality analysis using the BstXI PGK gene polymorphism showed that granulocytes were nonclonal in all patients during cytogenetic remission. BCR region studies showed rearrangement only in the one patient whose remission was incomplete at the time of sampling. Granulopoiesis is nonclonal in IFN-induced remissions of CML and may be derived from normal hematopoietic stem cells.
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Dyas CH, Simmons TK, Ellis CN, Austin JM, Partridge EE, Kilgore LC, Reading C, Nelson K, Blakemore WS. Effect of deoxyribonucleic acid ploidy status on survival of patients with carcinoma of the endometrium. SURGERY, GYNECOLOGY & OBSTETRICS 1992; 174:133-6. [PMID: 1734571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
This retrospective study was performed to determine the clinical usefulness of deoxyribonucleic acid (DNA) ploidy and the amount of DNA in the nucleus of the tumor cell on the prognosis of patients with carcinoma of the endometrium. Five year follow-up study was obtained for 121 patients. Flow cytometric analysis was used to determine tumor cell ploidy from paraffin-embedded specimens. Patients were grouped according to ploidy, clinical stage and grade and whether or not they received postoperative radiation. The data were subjected to a Cox proportional hazards regression analysis, and only ploidy status and clinical stage were significantly associated with survival time. Of the 121 patients observed, 44.6 per cent were aneuploid and 55.4 per cent, euploid. Preliminary chi-square analysis indicated a strong survival advantage to those patients with euploid endometrial carcinoma. The over-all five year survival rate for patients with aneuploid tumors was 53.7 per cent, as opposed to 80.6 per cent for patients with euploid tumors (p less than 0.01). Eighty-seven patients were Stage I, 39 aneuploid, 48 euploid. The five year survival rate for patients with Stage I aneuploid was 71.8 versus 85.4 per cent for those who were euploid. Twenty-one patients were Stage II; seven aneuploid and 14 euploid. The five year survival rate for aneuploid patients was 14.3 versus 85.7 per cent for euploid patients. The over-all five year survival rate for those with Stage I and II was 85.5 per cent euploid and 63.0 per cent aneuploid, p less than 0.05. Patients with Stage III or IV had poor outcome regardless of ploidy status. These data show that patients with euploid Stage I and II carcinoma of the endometrium have a significant survival advantage over patients with aneuploid tumors. We, therefore, believe that ploidy status may be used to facilitate the determination of prognosis in carcinoma of the endometrium.
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Claxton D, Suh SP, Filaccio M, Ellerson D, Gaozza E, Andersson B, Brenner M, Reading C, Feinberg A, Moen R. Molecular analysis of retroviral transduction in chronic myelogenous leukemia. Hum Gene Ther 1991; 2:317-21. [PMID: 1665348 DOI: 10.1089/hum.1991.2.4-317] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
We have developed a polymerase chain reaction (PCR) assay for detection of integrated retroviral transgenomes containing the neo G418 resistance gene in colonies (40 cells or more) grown in G418 selection after exposure to the neo-positive retrovirus LNL6. This assay also provides for simultaneous characterization of these colonies as belonging to a chronic myelogenous leukemic (bcr-abl positive) or nonleukemic population (bcr-abl negative). Using these techniques, we assessed transduction of the LNL6 retrovirus into the normal and leukemic cells of a blast-crisis chronic myelogenous leukemia (CML) patient. This work was designed to support the use of the LNL6 retroviral marker to help identify the origin of relapse after autologous marrow infusion. The data from these experiments show that the majority of CML blast crisis cells that, following exposure to the LNL6 virus, produce colonies under rigorous G418 selection are indeed transduced by the virus, as shown by the presence of the neo retroviral gene. Most of these colonies are also shown to be leukemic by PCR detection of the bcr-abl RNA. This demonstrates the feasibility of the study of CML marrow for retroviral marking. These procedures will be of use in establishing if relapse arises from leukemic blasts which contaminate purged autologous bone marrow infused following intensive therapy for leukemia.
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MESH Headings
- Base Sequence
- Biomarkers, Tumor/analysis
- Blast Crisis/pathology
- Blast Crisis/surgery
- Bone Marrow Purging
- Bone Marrow Transplantation
- Drug Resistance, Microbial
- Fusion Proteins, bcr-abl/analysis
- Genetic Markers
- Genetic Vectors
- Humans
- Kanamycin Kinase
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/pathology
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/surgery
- Molecular Sequence Data
- Neomycin/pharmacology
- Neoplasm Recurrence, Local
- Neoplastic Stem Cells/metabolism
- Neoplastic Stem Cells/pathology
- Phosphotransferases/analysis
- Phosphotransferases/genetics
- Polymerase Chain Reaction
- RNA, Messenger/analysis
- RNA, Neoplasm/analysis
- Recombinant Proteins/analysis
- Recombinant Proteins/genetics
- Retroviridae/genetics
- Transduction, Genetic
- Transplantation, Autologous
- Tumor Cells, Cultured
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30
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Seong D, Sims S, Johnson E, Lyding J, Lopez A, Garovoy M, Talpaz M, Kantarjian H, Lopez-Berestein G, Reading C. Activation of class I HLA expression by TNF-alpha and gamma-interferon is mediated through protein kinase C-dependent pathway in CML cell lines. Br J Haematol 1991; 78:359-67. [PMID: 1908310 DOI: 10.1111/j.1365-2141.1991.tb04449.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The combination of tumour necrosis factor alpha (TNF alpha) and gamma-interferon induced transcription of class I HLA genes in chronic myelogenous leukaemia (CML) cell lines through the formation of a complex between nuclear proteins and the transcriptional enhancers associated with these genes. Although gamma-interferon or TNF-alpha stimulated expression of class I HLA antigens in the EM2 and K562 CML cell lines when used alone, the effect of the combination of TNF-alpha and gamma-interferon was greater than that observed with either agent alone. The induction of class I HLA expression by gamma-interferon and TNF-alpha was inhibited completely by the isoquinoline sulfonamide H7, an inhibitor of protein kinase C. We conclude that the enhancement of the gamma-interferon induced transcriptional activation of class I HLA gene expression by TNF-alpha involves a protein kinase C-dependent pathway.
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MESH Headings
- Base Sequence
- Cell Division
- Cell Line
- Enhancer Elements, Genetic
- Gene Expression
- Genes, MHC Class I/drug effects
- Interferon-gamma/pharmacology
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/enzymology
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics
- Molecular Sequence Data
- Nuclear Proteins/metabolism
- Protein Kinase C/metabolism
- RNA, Messenger/analysis
- Transcription, Genetic/drug effects
- Tumor Cells, Cultured/drug effects
- Tumor Necrosis Factor-alpha/pharmacology
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31
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Blanchflower SE, Banks RM, Everett JR, Manger BR, Reading C. New paraherquamide antibiotics with anthelmintic activity. J Antibiot (Tokyo) 1991; 44:492-7. [PMID: 2061192 DOI: 10.7164/antibiotics.44.492] [Citation(s) in RCA: 83] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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32
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Abstract
Hot flushes were caused by hot drinks, alcohol, radiant heaters and thermal blankets in men undergoing treatment for carcinoma of the prostate and in menopausal women. Avoiding or changing these commonplace stimuli appears to reduce the frequency of flushing.
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33
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Ellis CN, Frey ES, Burnette JJ, Akin JM, Reading C, Gaskin TA, Blakemore WS. The content of tumor DNA as an indicator of prognosis in patients with T1N0M0 and T2N0M0 carcinoma of the breast. Surgery 1989; 106:133-8. [PMID: 2763022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
To determine if the flow cytometric measurement of the content of the tumor DNA could provide prognostic information in T1N0M0 and T2N0M0 carcinoma of the breast, we isolated nuclei from paraffin-embedded tumor specimens from 128 consecutive patients who underwent modified radical mastectomy and were found to have a T1 or T2N0M0 carcinoma of the breast. The content of DNA of the nuclei was determined by flow cytometry. Although the average tumor size was not significantly different, 17 of 56 patients with aneuploid tumors died of cancer compared with 2 of 72 with euploid tumors. The 10-year overall actuarial survival rate of the euploid and aneuploid groups was 72% and 67%, respectively (p less than 0.02). A hazards model of the data shows that the DNA content of the tumor is the most significant indicator of prognosis, with a 2.25-fold increased risk of death for patients with aneuploid tumors. These data show that the tumor DNA content can be used to identify a group of patients with T1 or T2N0M0 carcinoma of the breast with the same prognosis as a group of patients without carcinoma of the breast that would be unlikely to benefit from adjuvant therapy.
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34
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Farmer TH, Reading C. The effects of clavulanic acid sulbactam on induction of class 1 beta-lactamase. J Chemother 1989; 1:331-3. [PMID: 16312426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
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35
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O'Kennedy R, Bator JM, Reading C. A microassay for the determination of iodide and its application to the measurement of the iodination of proteins and the catalytic activities of iodo compounds. Anal Biochem 1989; 179:138-44. [PMID: 2757187 DOI: 10.1016/0003-2697(89)90214-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
A microassay system based on the effect of the catalytic Sandell-Kolthoff reaction of iodide on the oxidation of arsenic(III) by cerium(IV) was developed to measure iodine-containing compounds. This rapid assay uses small quantities of reagents, is suitable for use with a photometric microplate reader, can test many samples simultaneously, and eliminates problems associated with the use of radiolabeled compounds to measure iodination. It can detect picogram quantities of iodide. We report the use of this assay to measure the conjugation of an iodine-containing hapten (iodinated Bolton-Hunter reagent, IBHR) to ovalbumin and human serum albumin. It has proven to be excellent for studying the relative molar catalytic activity of the iodine-containing compounds IBHR, thyroxine, 4-iodophenol, and lithium 3,4-diiodosalicylate. The interference by azide on the assay was investigated.
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36
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Farmer TH, Reading C. The effects of clavulanic acid and sulbactam on beta-lactamase biosynthesis. J Antimicrob Chemother 1988; 22:105-11. [PMID: 3263350 DOI: 10.1093/jac/22.2.105] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Clavulanic acid and sulbactam were tested as inducers of beta-lactamase in 21 strains of Gram-negative bacteria. beta-Lactamase synthesis was inducible in all these strains, as demonstrated by the increased enzyme activities obtained when cells were grown in the presence of 10 mg/l of cefoxitin, the increase varying from 11- to 734-fold However, at the same concentration, neither inhibitor induced significant amounts of beta-lactamase, except in one strain of Providencia rettgeri, where both were potent inducers. When steps were taken to overcome the inhibitory effects of clavulanic acid and sulbactam, they were still found to be ineffective inducers. We conclude that, at therapeutic concentrations, clavulanic acid and sulbactam are generally poor inducers of beta-lactamase. Amoxycillin and ampicillin induced more beta-lactamase than the inhibitors, but were much less effective than cefoxitin, except for the strain of Prov. rettgeri.
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37
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Farmer TH, Reading C. Induction of the beta-lactamases of a strain of Pseudomonas aeruginosa, Morganella morganii and Enterobacter cloacae. J Antimicrob Chemother 1987; 19:401-4. [PMID: 3106306 DOI: 10.1093/jac/19.3.401] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
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38
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George NJ, Reading C. Sympathetic nervous system and dysfunction of the lower urinary tract. Clin Sci (Lond) 1986; 70 Suppl 14:69s-76s. [PMID: 3720192 DOI: 10.1042/cs070s069] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Careful clinical and investigative protocols allow the identification of a homogeneous group of patients with prostatodynia or 'anxious bladder syndrome' (underactive detrusor function). Psychophysiological studies and urodynamic measurements in such patients demonstrate remarkably consistent results, which, whilst lending support to the hypothesis that the sympathetic nervous system may effect bladder and urethral function, do not offer objective proof that adrenergic mechanisms are directly responsible for the observed dysfunctional state. observed dysfunctional state.
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39
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Reading C, Cole M. Structure-activity relationships amongst beta-lactamase inhibitors. JOURNAL OF ENZYME INHIBITION 1986; 1:83-104. [PMID: 3334242 DOI: 10.3109/14756368609020108] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Using a variety of beta-lactamases including those from Escherichia coli (TEM-1), Enterobacter cloacae P99 and Staphylococcus aureus the inhibition profiles (I50 values) were determined for various groups of compounds including penicillins, penicillanic acid derivatives (sulphone and beta-halo substitutions), olivanic acids and clavulanic acid derivatives including substituted ethers and amines. Some of the latter compounds had higher activity than clavulanic acid with and without preincubation of enzyme with inhibitor but they still had poor activity against the P99 enzyme. Improvements in activity against Class I cephalosporinases were obtained with some derivatives of clavulanic acid but this was usually achieved at the expense of activity against clavulanate susceptible beta-lactamases. The olivanic acids had the highest activity against the widest range of beta-lactamases.
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40
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Farmer T, Reading C. Inhibition of the beta-lactamases of Branhamella catarrhalis by clavulanic acid and other inhibitors. Drugs 1986; 31 Suppl 3:70-8. [PMID: 3488199 DOI: 10.2165/00003495-198600313-00015] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The beta-lactamases of Branhamella catarrhalis Ravasio and strain 1908 were readily inhibited by low concentrations of sulbactam, beta-halopenicillanic acids, MM 13902 and clavulanic acid. More detailed studies on the interaction of the Ravasio beta-lactamase with clavulanic acid demonstrated that the enzyme had high affinity for the inhibitor (Ki = 0.07 mumol/L) and was rapidly inhibited (t1/2 = 21 sec, kinhib. = 0.033/sec). Two types of enzyme-inhibitor complex were formed, a transiently stable species (t1/2 = 5.3 minutes at pH 7.3 and 37 degrees C) and a more stable species (t1/2 approximately equal to 2 hours at pH 7.3 and 37 degrees C). Irreversible inactivation of the enzyme was not achieved. Permeability studies on whole cells showed that beta-lactam antibiotics and beta-lactamase inhibitors readily penetrated the outer membrane of B. catarrhalis.
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42
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Abstract
The stability of temocillin to 12 different beta-lactamase preparations was studied using high pressure liquid chromatography and was compared with that of aztreonam, cefotetan and cefotaxime. Temocillin was the most stable beta-lactam examined, being as stable as cefotetan to most of the beta-lactamases tested. However, cefotetan was hydrolysed at measurable rates by the beta-lactamase of Enterobacter cloacae P99, in contrast to temocillin which was completely stable to this enzyme. Aztreonam was hydrolysed at a slow rate by many of the preparations, being especially labile to the enzyme from Klebsiella oxytoca K1. Cefotaxime was hydrolysed at varying rates by all the preparations.
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43
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44
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Reading C, Farmer T, Cole M. The beta-lactamase stability of amoxycillin with the beta-lactamase inhibitor, clavulanic acid. J Antimicrob Chemother 1983; 11:27-32. [PMID: 6600741 DOI: 10.1093/jac/11.1.27] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The stability of low concentrations of amoxycillin in the presence of clavulanic acid (potassium salt) was determined for a wide range of clinically important beta-lactamases including the staphylococcal and TEM plasmid mediated enzymes. Even with enzyme preparations which completely hydrolysed the amoxycillin within a minute, clavulanic acid provided significant protection. The time course of the protection of amoxycillin reflected the time dependent action of clavulanic acid.
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45
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Foulstone M, Reading C. Assay of amoxicillin and clavulanic acid, the components of Augmentin, in biological fluids with high-performance liquid chromatography. Antimicrob Agents Chemother 1982; 22:753-62. [PMID: 7181486 PMCID: PMC185656 DOI: 10.1128/aac.22.5.753] [Citation(s) in RCA: 156] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Augmentin is a new antibacterial formulation comprised of amoxicillin and the beta-lactamase inhibitor clavulanic acid. In the present paper, the use of high-performance liquid chromatography (HPLC) to provide a rapid assay of the components of Augmentin in body fluids is described. Clavulanic acid was assayed by reacting the sample with imidazole, which readily produces a derivative absorbing at 311 nm. This derivative chromatographs on reverse-phase HPLC columns clear of interfering components in both human serum and urine. Concentrations of clavulanic acid as low as 0.1 microgram/ml were readily detectable in human serum with this procedure. There was no interference from amoxicillin, amoxicillin penicilloic acid, or the acid and alkali degradation products of clavulanic acid when this assay system was used. Amoxicillin in body fluids was assayed directly by HPLC without derivatization. The same chromatographic conditions were employed for the assay of amoxicillin and the clavulanic acid derivative, simplifying the methodology. Amoxicillin, however, was determined of the antibiotic per ml. An alkali blanking procedure for amoxicillin and clavulanic acid is also described which allows the detection of any underlying peaks which may cochromatograph. The use of ultrafiltration to remove protein from serum samples before HPLC was successfully applied to the assay of clavulanic acid and amoxicillin. Ultrafiltration is not an essential procedure for these assays, but it prolongs column life and reduces interference in the amoxicillin assay. Results obtained by HPLC were compared with those obtained by using microbiological assays.
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Reading C, Osborn D, George N, Marklow C, Blacklock N. Prostatodynia: A preliminary psychophysiological investigation. Biol Psychol 1982. [DOI: 10.1016/0301-0511(82)90076-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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47
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Isaacs NS, Sunman G, Reading C. The inhibition of bacterial beta-lactamases by some monocyclic beta-lactams. J Antibiot (Tokyo) 1982; 35:589-93. [PMID: 6980873 DOI: 10.7164/antibiotics.35.589] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The inhibition characteristics of 25 monocyclic beta-lactams mainly with an amido function at C3 have been studied against the beta-lactamases produced by 4 bacterial types. Significant levels of inhibition were found for only a few of the compounds tested and primarily against Staphylococcus beta-lactamase. The most active inhibitor tested, 3-p-nitrophenylacetamido-4-phenylazetidin-2-one, was found to require a cis geometry, the trans isomer being almost inactive.
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48
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Farmer T, Reading C. beta-Lactamases of Branhamella catarrhalis and their inhibition by clavulanic acid. Antimicrob Agents Chemother 1982; 21:506-8. [PMID: 6980625 PMCID: PMC181924 DOI: 10.1128/aac.21.3.506] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Three of four clinical isolates of Branhamella catarrhalis from Belgium produced a beta-lactamase identical to enzymes previously reported to occur in French and British isolates of this organism. One strain, however, produced a new type of beta-lactamase. Both beta-lactamase types were readily inhibited by low concentrations of clavulanic acid.
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49
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Osborn DE, George NJ, Rao PN, Barnard RJ, Reading C, Marklow C, Blacklock NJ. Prostatodynia--physiological characteristics and rational management with muscle relaxants. BRITISH JOURNAL OF UROLOGY 1981; 53:621-3. [PMID: 7032641 DOI: 10.1111/j.1464-410x.1981.tb03275.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Patients with a clinical diagnosis of prostatodynia were evaluated by bacteriological, urodynamic and psychological means. In a prospective study 27 patients were entered on a trial of phenoxybenzamine, baclofen and placebo. A 50% symptomatic response was reported with phenoxybenzamine.
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50
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Reading C, Farmer T. The inhibition of beta-lactamases from gram-negative bacteria by clavulanic acid. Biochem J 1981; 199:779-87. [PMID: 7041890 PMCID: PMC1163436 DOI: 10.1042/bj1990779] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The beta-lactamase from Klebsiella pneumoniae E70 behaved in a similar fashion to the TEM-2 plasmid mediated enzyme on reaction with clavulanic acid. Both enzymes produced two types of enzyme-clavulanate complex, a transiently stable species (t((1/2))=4min at pH7.3 and 37 degrees C) and irreversibly inhibited enzyme. In the initial rapid reaction (2.5min) the enzymes partitioned between the transient and irreversible complexes in the ratios 3:1 for TEM-2 beta-lactamase and 1:1 for Klebsiella beta-lactamase. Biphasic inactivation was observed for both enzymes and the slower second phase was rate limited by the decay of the transiently stable complex. This decay released free enzyme for further reaction with fresh clavulanic acid, the products again partitioning between transiently stable and irreversibly inhibited enzyme. This cycle continued until all the enzyme had been irreversibly inhibited. A 115 molar excess of inhibitor was required to achieve complete inactivation of TEM-2 beta-lactamase. Hydrolysis of clavulanic acid with product release appeared to occur with the inhibition reaction, which explained this degree of clavulanic acid turnover. The stoichiometry of the interaction with Klebsiella beta-lactamase was not examined. The penicillinase from Proteus mirabilis C889 was rapidly inhibited by low concentrations of clavulanic acid. The major product was a moderately stable complex (t((1/2))=40min at pH7.3 and 37 degrees C); the proportion of the enzyme that was irreversibly inactivated was small. The cephalosporinase from Enterobacter cloacae P99 had low affinity for the inhibitor and only reacted with high concentrations of clavulanic acid (k=4.0m(-1).s(-1)) to produce a relatively stable complex (t((1/2))=180min at pH7.3 and 37 degrees C). No irreversible inactivation of this enzyme was detected. The rates of decay of the clavulanate-enzyme complexes produced in reactions with Proteus and Enterobacter enzymes were markedly increased at acid pH.
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