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Chen Q, Johnson DM, Haudenschild DR, Goetinck PF. Cartilage matrix protein: expression patterns in chicken, mouse, and human. Ann N Y Acad Sci 1996; 785:238-40. [PMID: 8702140 DOI: 10.1111/j.1749-6632.1996.tb56271.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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Jones RN, Johnson DM, Erwin ME. In vitro antimicrobial activities and spectra of U-100592 and U-100766, two novel fluorinated oxazolidinones. Antimicrob Agents Chemother 1996; 40:720-6. [PMID: 8851600 PMCID: PMC163187 DOI: 10.1128/aac.40.3.720] [Citation(s) in RCA: 101] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Two new fluorinated oxazolidinones, U-100592 and U-100766, were evaluated against more than 659 gram-positive and -negative organisms and compared with glycopeptides, erythromycin, clindamycin, clinafloxacin, and chloramphenicol. U-100592 and U-100766 were usually equally potent, but the MICs at which 90% of the isolates are inhibited (MIC90s) of U-100592 for some staphylococci and enterococci were slightly lower than those of U-100766 (1 versus 2 micrograms/ml). The MIC90 of U-100592 and U-100766 for oxacillin-resistant Staphylococcus aureus was 2 micrograms/ml, the same as observed for oxacillin-susceptible strains. The oxazolidinone MICs for other Staphylococcus spp. were < or = 2 micrograms/ml (MIC50, 0.5 to 1 microgram/ml). All enterococci were inhibited by < or = 4 and < or = 2 micrograms of U-100592 and U-100766 per ml, respectively. Against 152 vancomycin-resistant enterococci (five species), both compounds had a narrow range of MICs (0.25 to 2 micrograms/ml) and a MIC90 of 1 microgram/ml. Corynebacterium jeikeium, Bacillus spp., and all tested streptococci were inhibited (< or = 4 micrograms/ml). Members of the family Enterobacteriaceae and other gram-negative bacilli were not susceptible (MIC50, > 64 micrograms/ml) to either oxazolidinone. Three potencies of U-100592 and U-100766 disks were tested (5, 15, and 30 micrograms), and acceptable correlations (r = 0.81 to 0.90) with the measured MICs were observed. Best discrimination of the tentatively susceptible organisms (MICs, < or = 4 micrograms/ml) was demonstrated with the 30-micrograms disk concentration. The oxazolidinones demonstrated a dominant bacteristatic action. These oxazolidinones (U-100592 and U-100766) appear promising for treatment of gram-positive organisms that demonstrate resistance to contemporary therapeutic agents.
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Dyck PJ, Zimmerman IR, Johnson DM, Gillen D, Hokanson JL, Karnes JL, Gruener G, O'Brien PC. A standard test of heat-pain responses using CASE IV. J Neurol Sci 1996; 136:54-63. [PMID: 8815179 DOI: 10.1016/0022-510x(95)00277-9] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Heat-pain threshold and stimulus response characteristics can be evaluated with graduated heating pulses from a radiant heat source or a contact thermode. Results may be used to: (1) evaluate differences in sensation among anatomical sites, sides of the body, and with development and aging; and (2) provide an end-point for the study of the efficacy of drugs; or to follow the course of sensory alteration in disease (medical practice, epidemiologic studies, and controlled clinical trials). Because there is great variability in how tests of this kind are performed and scored, comparisons of results among medical centers are difficult. To meet this need, we have developed, and here describe, a standardized and validated test of heat-pain. We use both pyramidal and trapezoid-shaped stimuli. The range of stimulus magnitudes we recommend is sufficient to test heat-pain at a sensitive region (the face) of young people and an insensitive region (the foot) of healthy old people. From tests on healthy subjects and patients, we find that neither our previously published forced-choice or 4, 2, and 1 stepping algorithms are suitable for testing heat-pain sensation. We, therefore, introduce the Non-Repeating Ascending with Null Stimuli (NRA-NS) algorithm which performs satisfactorily. The graphed data points of responses to increasingly stronger heat pulses were made up of two components-the no pain (0) response line and the heat-pain response line (> or = 1 numerical scaling of the pain responses graded from 1 [least] to 10 [greatest]). For the pain responses, we found that usually a curve could be fit using a quadratic equation. Using this equation, or interpolation where necessary, it is possible to compute the heat-pain detection threshold (HPDT or HP:0.5), an intermediate heat-pain response (HP:5.0), and the difference between the two (HP:5.0-0.5). Our studies show that a certain time is needed between successive stimuli and tests to minimize changing basal skin temperature or threshold. We also demonstrated that low or high baseline skin temperatures can affect heat-pain responses, therefore, we advocate specific testing conditions. Based on a study of 25 healthy subjects, the reproducibility of the test falls within +/-1 stimulus steps 88% of the time for HP:5.0 and 76% of the time for HP:0.5. The precise approaches employed to make the test standard and reproducible are described. We illustrate that the algorithm and testing system is able to document altered pain threshold with skin abrasion, with intradermal injection of nerve growth factor, and with diabetic polyneuropathy.
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Cormican MG, Johnson DM, Jones RN. Activity of the quinupristin-dalfopristin combination (RP-59500; Synercid) tested against vancomycin-resistant Enterococcus species. Diagn Microbiol Infect Dis 1996; 24:59-60. [PMID: 8988766 DOI: 10.1016/0732-8893(95)00149-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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Johnson DM, Jones RN. Two investigational glycylcyclines, DMG-DMDOT and DMG-MINO. Antimicrobial activity studies against gram-positive species. Diagn Microbiol Infect Dis 1996; 24:53-7. [PMID: 8988765 DOI: 10.1016/0732-8893(95)00250-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
DMG-DMDOT (CL-331,002 OR CL-331,928) and DMG-MINO (CL-329,998 or CL-344,677) are two new semisynthetic tetracyclines called glycylcyclines, with a broad spectrum of activity and includes Enterobacteriaceae, Gram-positive cocci, JK diphtheroids, and Bacillus cereus. Potent activity was demonstrated against all Streptococcus spp. strains [minimum inhibitory concentrations] (MIC90S) 0.06-0.25 micrograms/ml) and staphylococci (oxacillin susceptible ans resistant; MIC90S 0.12-2 micrograms/ml). Both glycylcyclines (MIC90, 0.06 micrograms/ml) were more potent than minocycline (MIC90 8 micrograms/ml) against Enterococcus faecium, many of which were vancomycin resistant (116 strains). Organisms with minocycline MICs at > or = 8 micrograms/ml (Staphylococcus aureus, enterococci, beta-hemolytic streptococci, and pneumococci) had glycylcycline MIC results ranging from 0.06 to 0.5 micrograms/ml (e.g., apparent use against existing tetracycline-resistance phenotypes). Drugs in this class appear promising for therapy of infections caused by Gram-positive species now testing resistant to contemporary antimicrobial agents, and further development of compounds in this class is encouraged.
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Rademaker JW, Rainsford KD, Stetsko PI, Johnson DM, Chiba N, McDonald TM, Hunt RH. The effect of indomethacin-induced gastric mucosal injury on 24-h intragastric acidity and plasma gastrin concentration in healthy volunteers. Aliment Pharmacol Ther 1995; 9:625-31. [PMID: 8824649 DOI: 10.1111/j.1365-2036.1995.tb00431.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
AIMS To determine the influences of prostaglandin inhibition by indomethacin on 24-h intragastric acidity and plasma gastrin concentration, related to gastric mucosal injury. METHODS A pre- and post-treatment study design was employed in 10 Helicobacter pylori negative healthy male subjects. All subjects underwent upper gastrointestinal endoscopy at least 3 days before and after 7 days dosing with indomethacin 50 mg t.d.s. Mucosal damage was scored according to the Lanza method, and biopsies were taken for H. pylori status and assay of mucosal concentrations of prostaglandin (PG)E2 and leukotriene (LT)B4. Before and on the last day of dosing, intragastric acidity was measured by continuous 24-h pH monitoring, and plasma gastrin levels determined by radioimmunoassay in blood samples collected over the same period. RESULTS All subjects completed the study and no serious adverse events were reported. The mucosal injury score increased significantly from 0 (0-2) to 3.4 (0-8) (mean and range of values, P < 0.05) after dosing with indomethacin. No differences were observed in 24-h mean pH or meal stimulated plasma gastrin concentrations. Mucosal PGE2 and LTB4 were unchanged 8-10 h after the last indomethacin dose. CONCLUSIONS Endogenous prostaglandins do not appear to alter intragastric acidity or gastrin secretion, in contrast to the PGE analogues, whose effects must be more pharmacological than physiological.
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Chen Q, Johnson DM, Haudenschild DR, Tondravi MM, Goetinck PF. Cartilage matrix protein forms a type II collagen-independent filamentous network: analysis in primary cell cultures with a retrovirus expression system. Mol Biol Cell 1995; 6:1743-53. [PMID: 8590802 PMCID: PMC301329 DOI: 10.1091/mbc.6.12.1743] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Cartilage matrix protein (CMP) is expressed specifically in mature cartilage and consists of two von Willebrand factor A domains (CMP-A1 and CMP-A2) that are separated by an epidermal growth factor-like domain, and a coiled-coil tail domain at the carboxyl terminal end. We have shown previously that CMP interacts with type II collagen-containing fibrils in cartilage. In this study, we describe a type II collagen-independent CMP filament and we analyze the structural requirement for the formation of this type of filament. Recombinant wild-type CMP and two mutant forms were expressed in chick primary cell cultures using a retrovirus expression system. In chondrocytes, the wild-type virally encoded CMP is able to form disulfide bonded trimers and to assemble into filaments. Filaments also form with CMP whose Cys455 and Cys457 in the tail domain were mutagenized to prevent interchain disulfide bond formation. Therefore, intermolecular disulfide bonds are not necessary for the assembly of CMP into filaments. Both the wild-type and the double cysteine mutant also form filaments in fibroblasts, indicating that chondrocyte-specific factors are not required for filament formation. A truncated form of CMP that consists only of the CMP-A2 domain and the tail domain can form trimers but fails to form filaments, indicating that the deleted CMP-A1 domain and/or the epidermal growth factor domain are necessary for filament assembly but not for trimer formation. Furthermore, the expression of the virally encoded truncated CMP in chondrocyte culture disrupts endogenous CMP filament formation. Together these data suggest a role for CMP in cartilage matrix assembly by forming filamentous networks that require participation and coordination of individual domains of CMP.
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Jones RN, Johnson DM, Biedenbach DJ, Marshall SA. Activity of two novel fluoroquinolones (DU-6859a and DV-7751a) tested against glycopeptide-resistant enterococcal isolates. Diagn Microbiol Infect Dis 1995; 23:123-7. [PMID: 8849658 DOI: 10.1016/0732-8893(95)00168-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Two novel fluoroquinolones, DU-6859a and DV-7751a, were compared with three peer compounds (ciprofloxacin, levofloxacin, and ofloxacin) by testing 150 strains of enterococci that were resistant to vancomycin. Standardized methods recommended by the National Committee for Clinical Laboratory Standards were used for all minimum inhibitory concentration tests, and DU-6859a was additionally tested by the standardized disk diffusion procedure (5-mu g disks). The rank order of the fluoroquinolone spectrums against these Enterococcus spp. isolates was DU-6859a (71.3% of strains inhibited at < or = 2 mu g/ml) > DV-7751a (38.7%) > levofloxacin (33.3%) > ofloxacin (32.0%) > ciprofloxacin (3.3%). Using previously proposed break point zone diameters of > or = 16 mm (susceptible) and < or = 12 mm (resistant), the DU-6859a disk diffusion tests for these glycopeptide-resistant organisms were without false-susceptible or false-resistant error (81.3% absolute agreement). These results indicate that among the investigational and currently marketed fluoroquinolones, DU-6859a appears to have the greatest potential value in the therapy of Enterococcus spp. strains that are resistant to the glycopeptides and many other therapeutic agents.
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Chen Q, Johnson DM, Haudenschild DR, Goetinck PF. Progression and recapitulation of the chondrocyte differentiation program: cartilage matrix protein is a marker for cartilage maturation. Dev Biol 1995; 172:293-306. [PMID: 7589809 DOI: 10.1006/dbio.1995.0024] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
During endochondral bone formation, chondrocytes in the cartilaginous anlage of long bones progress through a spatially and temporally regulated differentiation program before being replaced by bone. To understand this process, we have characterized the differentiation program and analyzed the relationship between chondrocytes and their extracellular environment in the regulation of the program. Our results indicate that, within an epiphyseal growth plate, the zone of proliferating chondrocytes is not contiguous with the zone of hypertrophic chondrocytes identified by the transcription of the type X collagen gene. We find that the postproliferative chondrocytes which make up the zone between the zones of proliferation and hypertrophy specifically transcribe the gene for cartilage matrix protein (CMP). This zone has been termed the zone of maturation. The identification of this unique population of chondrocytes demonstrates that the chondrocyte differentiation program consists of at least three stages. CMP translation products are present in the matrix surrounding the nonproliferative chondrocytes of both the zones of maturation and hypertrophy. Thus, CMP is a marker for postmitotic chondrocytes. As a result of the changes in gene expression during the differentiation program, chondrocytes in each zone reside in an extracellular matrix with a unique macromolecular composition. Chondrocytes in primary cell culture can proceed through the same differentiation program as they do in the cartilaginous rudiments. In culture, a wave of differentiation begins in the center of a colony and spreads to its periphery. The cessation of proliferation coincides with the appearance of CMP and eventually the cells undergo hypertrophy and synthesize type X collagen. These results reveal distinct switches at the proliferative-maturation transition and at the maturation-hypertrophy transition during chondrocyte differentiation and indicate that chondrocytes synthesize new matrix molecules and thus modify their preexisting microenvironment as differentiation progresses. However, when "terminally" differentiated hypertrophic chondrocytes are released from their surrounding environment and incubated in pellet culture, they stop type X collagen synthesis, resume proliferation, and reinitiate aggrecan synthesis. Eventually they cease proliferation and reinitiate CMP synthesis and finally type X collagen. Thus they are capable of recapitulating all three stages of the differentiation program in vitro. The data suggest a high degree of plasticity in the chondrocyte differentiation program and demonstrate that the progression and maintenance of this program is regulated, at least in part, by the extracellular environment which surrounds a differentiating chondrocyte during endochondral bone formation.
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Jones RN, Johnson DM. Modifications for disk diffusion susceptibility testing criteria of clinafloxacin (CI-960, AM-1091, PD127371) and fleroxacin (Ro 23-6240, AM-833) following studies with a challenge panel of ciprofloxacin-resistant clinical isolates. Diagn Microbiol Infect Dis 1995; 21:209-13. [PMID: 7554803 DOI: 10.1016/0732-8893(94)00061-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
A collection of ciprofloxacin-resistant organisms (200 strains) was developed among 300 total test strains to "challenge" the initial interpretive criteria developed for clinafloxacin (formerly CI-960), fleroxacin (formerly Ro 23-6240, AM-833), and ciprofloxacin. Generated results indicate the necessity for modified criteria for disk diffusion tests (5-micrograms disks) as follows: for clinafloxacin, susceptible at > or = 21 mm ( < or = 1 microgram/ml) and resistant at < or = 17 mm ( > or = 4 micrograms/ml), or susceptible at > or = 19 mm ( < or = 2 micrograms/liter) and resistant at < or = 15 mm ( > or = 8 micrograms/ml); for fleroxacin, susceptible at > or = 16 mm ( < or = 2 micrograms/ml) and resistant at < or = 11 mm ( > or = 8 micrograms/ml); and for ciprofloxacin, resistant at < or = 17 mm > or = 4 micrograms/ml). These modifications maximize total absolute interpretive accuracy between the standardized test methods, especially minimizing the potential for false susceptibility (very major errors) when testing truly resistant isolates. The clinafloxacin spectrum was widest against these resistant isolates, and the other two tested fluoroquinolones (ciprofloxacin, fleroxacin) possessed comparable overall spectrums of activity, although ciprofloxacin was generally more active on a weight basis. We urge the rapid acceptance of these criteria to improve the accuracy of the widely used National Committee for Clinical Laboratory Standards method for disk diffusion tests.
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Sterns JB, Johnson DM. Financing alternatives for medical group practices. MEDICAL GROUP MANAGEMENT JOURNAL 1995; 42:58-62. [PMID: 10139543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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Parrish MB, Rainsford KD, Johnson DM, Daniel EE. NK1 receptors mediated release of 6-keto-PGF1 alpha from the ex vivo perfused canine ileum. J Pharmacol Exp Ther 1994; 271:39-47. [PMID: 7525925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The purpose of this study was to determine the effects of tachykinins on prostanoid production by the dog ileum and to characterize the tachykinin receptor(s) responsible for the principal eicosanoid shown to be released, 6-keto-PGF1 alpha. Substance P, the selective NK1 receptor agonist [Sar9,Met(O2)11]substance P and neurokinin A caused concentration-dependent production of 6-keto-PGF1 alpha; neurokinin A was least potent. The selective NK2 agonist [Nle10]neurokinin A(4-10) had no effect. The selective NK1 antagonist CP-96,345 (10(-7) M), blocked 6-keto-PGF1 alpha release from substance P (10(-7) M), [Sar9,Met(O2)11]substance P (10(-7) M) and neurokinin A (10(-7) M). Although the putative NK2 antagonist MEN 10207 (10(-7) M) partially blocked the 6-keto-PGF1 alpha release induced by neurokinin A (10(-7) M), we conclude that all these peptides acted primarily on NK1 receptors to induce 6-keto-PGF1 alpha. Additional experiments suggest that a major site of production of 6-keto-PGF1 alpha in the canine ileum may be the vasculature, but these experiments do not exclude other sources such as intestinal muscle for this prostanoid. Calcium-free Krebs' solution partially reduced the release of 6-keto-PGF1 alpha to substance P (10(-7) M), implying that extracellular calcium helps support tachykinin-induced production of 6-keto-PGF1 alpha. Blockade of synthesis of another vasoactive mediator, endothelium-derived relaxing factor (nitric oxide), by N omega-L-arginine methyl ester) did not alter substance P-induced release of 6-keto-PGF1 alpha.(ABSTRACT TRUNCATED AT 250 WORDS)
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Johnson DM, Sapirstein W. FDA's requirements for in-vivo performance data for prosthetic heart valves. THE JOURNAL OF HEART VALVE DISEASE 1994; 3:350-5. [PMID: 7952304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The Food and Drug Administration (FDA) has recently revised its "Replacement Heart Valve Guidance". That document lists the data FDA deems necessary to support the approval of new prosthetic heart valves of all designs, and which should be contained in Premarket Approval Applications for these devices. The guidance covers detailed data requirements for in vitro, animal, and clinical data. This paper is intended to briefly summarize FDA's requirements for in vivo and clinical data. The clinical study must establish that the device is both safe and effective, as compared to currently marketed replacement heart valves. It is possible to achieve this goal using hypothesis testing to compare the results of an observational study against a set of Objective Performance Criteria (OPC) which have been established by the FDA. The establishment of the OPCs was facilitated by a standardized set of definitions of complications published by the American Association of Thoracic Surgery and Society of Thoracic Surgeons (AATS/STS) in 1987/1988. Papers published in peer reviewed journals have utilized this set of definitions for data analysis, providing an ample pool of data from which to establish OPCs. The number of patients required to establish the safety and efficacy of a replacement heart valve, using this approach, is 800 valve years, 400 in the aortic and 400 in the mitral position. Advantages of this approach are reduction in the number of patients and duration of the study.
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Johnson DM, Chwirut DJ, Regnault WF. FDA's requirements for in-vitro performance data for prosthetic heart valves. THE JOURNAL OF HEART VALVE DISEASE 1994; 3:228-34. [PMID: 8087255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The Center for Devices and Radiological Health, Food and Drug Administration, has recently revised its "Replacement Heart Valve Guidance". That document lists the data FDA deems necessary to support the approval of new prosthetic heart valves of all designs, and which should be contained in Premarket Approval Applications for these devices. The Guidance covers detailed data requirements for in vitro, animal, and clinical data. This paper is intended to briefly summarize FDA's requirements for in vitro data, and, for those cases where it may not be obvious, to provide an overview of the significance of these data and how FDA interprets them in the approval decision process.
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Jones RN, Johnson DM, Erwin ME. Interpretive criteria for DU-6859a disk diffusion tests using 5-micrograms disks. Diagn Microbiol Infect Dis 1994; 18:125-7. [PMID: 8062531 DOI: 10.1016/0732-8893(94)90078-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
In vitro disk diffusion test interpretive criteria were developed for DU-6859a, a new difluorinated quinolone, using a 5-micrograms disk. Included in the 494 organisms tested were 84 (17%) ciprofloxacin-resistant > or = 4 micrograms/ml) clinical isolates. The following interpretive criteria were proposed for two possible susceptible breakpoint minimum inhibitory concentrations: > or = 16 mm (< or = 2 micrograms/ml) = susceptible and < or = 12 mm (> or = 8 micrograms/ml) = resistant and; > or = 19 mm (< or = 1 microgram/ml) = susceptible and < or = 15 mm (> or = 4 micrograms/ml) = resistant. These criteria demonstrated > or = 97% absolute interpretive agreement between test methods with no major (false resistant) or very major (false susceptible) errors.
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Grunkemeier GL, Johnson DM, Naftel DC. Sample size requirements for evaluating heart valves with constant risk events. THE JOURNAL OF HEART VALVE DISEASE 1994; 3:53-8. [PMID: 8162217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A method is described for computing sample size requirements for a clinical study of a new heart valve, according to the guidance document recently revised by the FDA. The FDA requirements specify a one-sample hypothesis test in which the complication rates for the study valve are compared to fixed values determined from previous experience with approved devices. These values, which can differ for different complications and for mechanical or tissue valve types, are called OPC's (Objective Performance Criteria). The method described, using the Poisson distribution, provides a simple formula for computing the valve-years required corresponding to any OPC. At the OPC level required by the FDA guidelines (1.2%/year), the minimum follow-up necessary is about 800 valve-years.
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Johnson DM, Jones RN, Erwin ME. In vitro antimicrobial activity of CP-99433 compared with other fluoroquinolones. Diagn Microbiol Infect Dis 1993; 17:79-83. [PMID: 8359012 DOI: 10.1016/0732-8893(93)90076-j] [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: 01/30/2023]
Abstract
CP-99433 is a new C-7 diazabicyclofluoroquinolone with a broad spectrum of activity that includes Enterobacteriaceae, Gram-positive cocci, and nonenteric Gram-negative bacilli. Potent activity was demonstrated against Pseudomonas aeruginosa [minimum inhibitory concentration (MIC90, 0.5 microgram/ml), Xanthomonas maltophilia (MIC90, 1 microgram/ml), and all Streptococcus species (MIC90s, 0.25-1 microgram/ml). Only CP-99433 was active against Enterococcus faecium (MIC50, 2 micrograms/ml). CP-99433 also demonstrated activity against several ciprofloxacin-resistant staphylococci. Additional studies of CP-99433 activity appear indicated.
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Rainsford KD, James C, Johnson DM, Stetsko PI, Hill RE, Salena BJ, Hunt RH. Effects of chronic NSAIDs on gastric mucosal injury related to mucosal prostanoids, and plasma drug concentrations in human volunteers. AGENTS AND ACTIONS 1993; 39 Spec No:C21-3. [PMID: 8273571 DOI: 10.1007/bf01972708] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The relationship between endoscopically observed gastric mucosal damage, elicited following repeated oral intake for 7 d of four NSAIDs, to their effects on antral and fundic production of PGE2, 6-keto-PGF1 alpha and TxB2 (assayed by GC-MS), mucosal histology and plasma concentration profiles was studied in 40 normal males. Subjects received azapropazone (APZ) 600 mg b.i.d., indomethacin (IND) 50 mg t.i.d., naproxen (NAP) 500 mg b.i.d., piroxicam (PIR) 20 mg qq.d., or one placebo capsule t.i.d. (N = 8/group). Plasma NSAIDs (HPLC) levelled at 7 d. Mucosal damage occurred in the antrum region with IND and NAP. APZ and PIR exhibited no differences compared to placebo. NAP and IND reduced all three prostanoids in the antrum while APZ and PIR were ineffective. Fundic PGE2 was reduced by IND, NAP and PIR; APZ had no effects. Thus, mucosal damage relates to effects on prostanoid production in the antrum but not in the fundus.
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Woolner DF, Johnson DM. Bilateral pneumothorax and surgical emphysema associated with laparoscopic cholecystectomy. Anaesth Intensive Care 1993; 21:108-10. [PMID: 8447579 DOI: 10.1177/0310057x9302100128] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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Gooding BB, Erwin ME, Barrett MS, Johnson DM, Jones RN. Antimicrobial activities of two investigational fluoroquinolones (CI-960 and E4695) against over 100 Legionella sp. isolates. Antimicrob Agents Chemother 1992; 36:2049-50. [PMID: 1329642 PMCID: PMC192436 DOI: 10.1128/aac.36.9.2049] [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: 12/26/2022] Open
Abstract
The antimicrobial activities of two investigational fluoroquinolones (CI-960 and E4695) were compared with those of five similar compounds and four comparison drugs against 103 strains of Legionella pneumophila and five other Legionella species type strains. When concentrations inhibiting 90% of strains tested (MIC90s) for L. pneumophila were determined, CI-960 and temafloxacin emerged as the most active (0.015 microgram/ml) and were followed in potency by E4695 (0.03 microgram/ml). This activity was two- to fourfold greater than that of the reference drug, ciprofloxacin, and approached that of rifampin (MIC90, 0.008 microgram/ml). All fluoroquinolones studied were more active than erythromycin (MIC90, 0.5 microgram/ml). These two investigational fluoroquinolones appear well suited for further in vivo study of legionellosis therapy.
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Johnson DM, Erwin ME, Barrett MS, Gooding BB, Jones RN. Antimicrobial activity of ten macrolide, lincosamine and streptogramin drugs tested against Legionella species. Eur J Clin Microbiol Infect Dis 1992; 11:751-5. [PMID: 1425738 DOI: 10.1007/bf01989985] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
RP59500, a semisynthetic pristinamycin combination, and 14 other antimicrobial agents were tested against 108 Legionella strains. Of the ten macrolide, lincosamine and streptogramin agents tested, the new streptogramin RP59500 ranked seventh in order of activity against Legionella pneumophila on the basis of MIC90 results as follows: clarithromycin = 14-OH clarithromycin (MIC90 0.12 mg/l) > roxithromycin > erythromycin = tylosin = virginiamycin > RP59500 (MIC90 1 mg/l) = azithromycin > dirithromycin > clindamycin (MIC90 8 mg/l). Of all 14 drugs tested in this study, rifampicin was the most potent with an MIC90 of 0.008 mg/l. In this retrospective study of Legionella strains (1981-1990 isolates), we observed no trend toward resistance to the agents investigated.
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Johnson DM. Community education programs specifically for children. J Pediatr Nurs 1992; 7:297-8. [PMID: 1507068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Johnson DM, Jones RN. Antibacterial activity of the investigational oral and parenteral cephalosporin BK-218. Eur J Clin Microbiol Infect Dis 1992; 11:181-8. [PMID: 1396735 DOI: 10.1007/bf01967075] [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: 12/26/2022]
Abstract
BK-218 is a novel cephalosporin with a dual route of administration and spectrum of activity most similar to that of second-generation cephalosporins. BK-218 was active against Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis but strains resistant to penicillins had higher MICs. BK-218 had greater activity (8-fold) than cefuroxime or cefaclor against oxacillin-susceptible Staphylococcus spp. Moderate BK-218 activity was observed against Neisseria gonorrhoeae and commonly isolated Enterobacteriaceae such as Escherichia coli (MIC90, 1 mg/l), Klebsiella spp. (MIC90, 2 mg/l), and Proteus mirabilis (MIC90, 2 mg/l). The following organisms were generally BK-218-resistant (MIC90, greater than 16 mg/l): Bacteroides fragilis, Pseudomonas spp., Acinetobacter spp., Xanthomonas maltophilia, Citrobacter spp., Enterobacter spp., indole-positive Proteus, Serratia spp., enterococci and oxacillin-resistant staphylococci.
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Puopolo PR, Volpicelli SA, Johnson DM, Flood JG. Emergency toxicology testing (detection, confirmation, and quantification) of basic drugs in serum by liquid chromatography with photodiode array detection. Clin Chem 1991; 37:2124-30. [PMID: 1764789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We investigated the applicability of liquid chromatography with photodiode array detection as a serum drug screening technique in an emergency toxicology setting. Basic compounds are extracted from alkalinized serum with hexane and chromatographed on a cyanopropyl reversed-phase column. The photodiode array detector records the ultraviolet spectrum of each eluting peak for identification and quantification. More than 30 drugs/metabolites including antidepressants, antihistamines, phenothiazines, and analgesics are detected at their therapeutic concentrations or less. Quantitative run-to-run precision (CV) for antidepressant drugs at low therapeutic concentrations is less than 6%. We evaluated the potential for interference of greater than 140 compounds of clinical interest. In a split-sample study, 151 of 154 positive drug findings by the method were confirmed by alternative techniques (gas chromatography/mass spectrometry and liquid chromatography with either normal-phase or reversed-phase columns). In the three unconfirmed findings, this method detected drugs at concentrations below the limit of identification of the comparison method. Also, 275 samples judged negative by this procedure were negative by a different liquid-chromatographic method.
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Jones RN, Erwin ME, Barrett MS, Briggs BM, Johnson DM. In vitro activity of RU29246. The metabolite of a new HR916 cephalosporin ester. Diagn Microbiol Infect Dis 1991; 14:473-83. [PMID: 1802534 DOI: 10.1016/0732-8893(91)90003-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Compound RU29246 (RU) is the active metabolite of an orally absorpted cephalosporin ester HR916. The RU spectrum of activity includes the majority of Enterobacteriaceae species, Haemophilus influenzae, pathogenic Neisseria spp., Moraxella catarrhalis, Acinetobacter antiratus, staphylococci, and Streptococcus spp. Pseudomonas species and enterococci were routinely resistant to RU. The RU spectrum was most similar to cefixime against the Gram-negative bacilli and to cefuroxime against the Gram-positive organisms. RU was bactericidal and its mean inhibitory concentrations (MICs) were not greatly increased by high inoculum concentrations. Many strains producing various beta-lactamases generally remained susceptible to RU by MIC tests. However, isolates with extended broad spectrum beta-lactamases capable of hydrolyzing cefotaxime and ceftazidime were also resistant to RU. Broth and agar RU MICs were comparable. Its activity was increased against enterococci in the presence of blood products.
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