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Slee EA, Keogh SA, Martin SJ. Cleavage of BID during cytotoxic drug and UV radiation-induced apoptosis occurs downstream of the point of Bcl-2 action and is catalysed by caspase-3: a potential feedback loop for amplification of apoptosis-associated mitochondrial cytochrome c release. Cell Death Differ 2000; 7:556-65. [PMID: 10822279 DOI: 10.1038/sj.cdd.4400689] [Citation(s) in RCA: 228] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
BID, a pro-apoptotic Bcl-2 family member, promotes cytochrome c release during apoptosis initiated by CD95L or TNF. Activation of caspase-8 in the latter pathways results in cleavage of BID, translocation of activated BID to mitochondria, followed by redistribution of cytochrome c to the cytosol. However, it is unclear whether BID participates in cytochrome c release in other (non-death receptor) cell death pathways. Here, we show that BID is cleaved in response to multiple death-inducing stimuli (staurosporine, UV radiation, cycloheximide, etoposide). However BID cleavage in these contexts was blocked by Bcl-2, suggesting that proteolysis of BID occurred distal to cytochrome c release. Furthermore, addition of cytochrome c to Jurkat post-nuclear extracts triggered breakdown of BID at Asp-59 which was catalysed by caspase-3 rather than caspase-8. We provide evidence that caspase-3 catalysed cleavage of BID represents a feedback loop for the amplification of mitochondrial cytochrome c release during cytotoxic drug and UV radiation-induced apoptosis.
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Eléouët JF, Slee EA, Saurini F, Castagné N, Poncet D, Garrido C, Solary E, Martin SJ. The viral nucleocapsid protein of transmissible gastroenteritis coronavirus (TGEV) is cleaved by caspase-6 and -7 during TGEV-induced apoptosis. J Virol 2000; 74:3975-83. [PMID: 10756009 PMCID: PMC111911 DOI: 10.1128/jvi.74.9.3975-3983.2000] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The transmissible gastroenteritis coronavirus (TGEV), like many other viruses, exerts much of its cytopathic effect through the induction of apoptosis of its host cell. Apoptosis is coordinated by a family of cysteine proteases, called caspases, that are activated during apoptosis and participate in dismantling the cell by cleaving key structural and regulatory proteins. We have explored the caspase activation events that are initiated upon infection of the human rectal tumor cell line HRT18 with TGEV. We show that TGEV infection results in the activation of caspase-3, -6, -7, -8, and -9 and cleavage of the caspase substrates eIF4GI, gelsolin, and alpha-fodrin. Surprisingly, the TGEV nucleoprotein (N) underwent proteolysis in parallel with the activation of caspases within the host cell. Cleavage of the N protein was inhibited by cell-permeative caspase inhibitors, suggesting that this viral structural protein is a target for host cell caspases. We show that the TGEV nucleoprotein is a substrate for both caspase-6 and -7, and using site-directed mutagenesis, we have mapped the cleavage site to VVPD(359) downward arrow. These data demonstrate that viral proteins can be targeted for destruction by the host cell death machinery.
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78
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Keogh SA, Walczak H, Bouchier-Hayes L, Martin SJ. Failure of Bcl-2 to block cytochrome c redistribution during TRAIL-induced apoptosis. FEBS Lett 2000; 471:93-8. [PMID: 10760520 DOI: 10.1016/s0014-5793(00)01375-2] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Tumour necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a member of the TNF family of cytokines that promotes apoptosis and NF-kappaB activation. Here we show that recombinant hu-TRAIL initiates the activation of multiple caspases, the loss of mitochondrial transmembrane potential, the cleavage of BID and the redistribution of mitochondrial cytochrome c. However, whereas Bcl-2 efficiently blocked UV radiation-induced cytochrome c release and consequent apoptosis of CEM cells, it failed to do either in the context of TRAIL treatment. Thus, TRAIL engages a death pathway that is at least partially routed via the mitochondria, but in contrast with other stimuli that engage this pathway, TRAIL-induced cytochrome c release is not regulated by Bcl-2.
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79
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Martin SJ, Bandey HL, Cernosek RW, Hillman AR, Brown MJ. Equivalent-circuit model for the thickness-shear mode resonator with a viscoelastic film near film resonance. Anal Chem 2000; 72:141-9. [PMID: 10655646 DOI: 10.1021/ac9908290] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We derive a lumped-element, equivalent-circuit model for the thickness-shear mode (TSM) resonator with a viscoelastic film. This modified Butterworth-Van Dyke model includes in the motional branch a series LCR resonator, representing the quartz resonance, and a parallel LCR resonator, representing the film resonance. This model is valid in the vicinity of film resonance, which occurs when the acoustic phase shift across the film is an odd multiple of pi/2 rad. For low-loss films, this model accurately predicts the frequency changes and damping that arise at resonance and is a reasonable approximation away from resonance. Elements of the parallel LCR resonator are explicitly related to film properties and can be interpreted in terms of elastic energy storage and viscous power dissipation. The model leads to a simple graphical interpretation of the coupling between the quartz and film resonances and facilitates understanding of the resulting responses. These responses are compared with predictions from the transmission-line and Sauerbrey models.
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80
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Bender F, Dahint R, Josse F, Ricco AJ, Martin SJ. Characteristics of acoustic plate modes on rotated Y-cuts of quartz utilized for biosensing applications. Anal Chem 1999; 71:5064-8. [PMID: 10575962 DOI: 10.1021/ac990559l] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Acoustic plate modes (APM) on various quartz substrates have been investigated in order to determine their usefulness for liquid-sensing applications. The modes have been characterized in terms of their mass sensitivity, mode separation, temperature sensitivity, and reproducibility of the experimental results. Promising characteristics are found for rotated Y-cuts of quartz with the direction of acoustic mode propagation being perpendicular to the X-axis of the quartz crystal. Experiments on the detection of immunochemical reactions are performed using different quartz APM sensors, and the results are compared to similar experiments utilizing APM devices on ZX-LiNbO3.
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81
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Slee EA, Adrain C, Martin SJ. Serial killers: ordering caspase activation events in apoptosis. Cell Death Differ 1999; 6:1067-74. [PMID: 10578175 DOI: 10.1038/sj.cdd.4400601] [Citation(s) in RCA: 319] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Caspases participate in the molecular control of apoptosis in several guises; as triggers of the death machinery, as regulatory elements within it, and ultimately as a subset of the effector elements of the machinery itself. The mammalian caspase family is steadily growing and currently contains 14 members. At present, it is unclear whether all of these proteases participate in apoptosis. Thus, current research in this area is focused upon establishing the repertoire and order of caspase activation events that occur during the signalling and demolition phases of cell death. Evidence is accumulating to suggest that proximal caspase activation events are typically initiated by molecules that promote caspase aggregation. As expected, distal caspase activation events are likely to be controlled by caspases activated earlier in the cascade. However, recent data has cast doubt upon the functional demarcation of caspases into signalling (upstream) and effector (downstream) roles based upon their prodomain lengths. In particular, caspase-3 may perform an important role in propagating the caspase cascade, in addition to its role as an effector caspase within the death programme. Here, we discuss the apoptosis-associated caspase cascade and the hierarchy of caspase activation events within it.
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82
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Riedel G, Micheau J, Lam AG, Roloff EL, Martin SJ, Bridge H, de Hoz L, Poeschel B, McCulloch J, Morris RG. Reversible neural inactivation reveals hippocampal participation in several memory processes. Nat Neurosci 1999; 2:898-905. [PMID: 10491611 DOI: 10.1038/13202] [Citation(s) in RCA: 358] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Studies of patients and animals with brain lesions have implicated the hippocampal formation in spatial, declarative/relational and episodic types of memory. These and other types of memory consist of a series of interdependent but potentially dissociable memory processes-encoding, storage, consolidation and retrieval. To identify whether hippocampal activity contributes to these processes independently, we used a novel method of inactivating synaptic transmission using a water-soluble antagonist of AMPA/kainate glutamate receptors. Once calibrated using electrophysiological and two-deoxyglucose techniques in vivo, drug or vehicle was infused chronically or acutely into the dorsal hippocampus of rats at appropriate times during or after training in a water maze. Our findings indicate that hippocampal neural activity is necessary for both encoding and retrieval of spatial memory and for either trace consolidation or long-term storage.
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83
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Adrain C, Slee EA, Harte MT, Martin SJ. Regulation of apoptotic protease activating factor-1 oligomerization and apoptosis by the WD-40 repeat region. J Biol Chem 1999; 274:20855-60. [PMID: 10409627 DOI: 10.1074/jbc.274.30.20855] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Apoptotic protease activating factor-1 (Apaf-1) has been identified as a proximal activator of caspase-9 in cell death pathways that trigger mitochondrial damage and cytochrome c release. The mechanism of Apaf-1 action is unclear but has been proposed to involve the clustering of caspase-9 molecules, thereby facilitating autoprocessing of adjacent zymogens. Here we show that Apaf-1 can dimerize via the CED-4 homologous and linker domains of the molecule providing a means by which Apaf-1 can promote the clustering of caspase-9 and facilitate its activation. Apaf-1 dimerization was repressed by the C-terminal half of the molecule, which contains multiple WD-40 repeats, but this repression was overcome in the presence of cytochrome c and dATP. Removal of the WD-40 repeat region resulted in a constitutively active Apaf-1 that exhibited greater cytotoxicity in transient transfection assays when compared with full-length Apaf-1. These data suggest a mechanism for Apaf-1 function and reveal an important regulatory role for the WD-40 repeat region.
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84
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Slee EA, Harte MT, Kluck RM, Wolf BB, Casiano CA, Newmeyer DD, Wang HG, Reed JC, Nicholson DW, Alnemri ES, Green DR, Martin SJ. Ordering the cytochrome c-initiated caspase cascade: hierarchical activation of caspases-2, -3, -6, -7, -8, and -10 in a caspase-9-dependent manner. J Cell Biol 1999; 144:281-92. [PMID: 9922454 PMCID: PMC2132895 DOI: 10.1083/jcb.144.2.281] [Citation(s) in RCA: 1480] [Impact Index Per Article: 59.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/1998] [Revised: 12/21/1998] [Indexed: 12/31/2022] Open
Abstract
Exit of cytochrome c from mitochondria into the cytosol has been implicated as an important step in apoptosis. In the cytosol, cytochrome c binds to the CED-4 homologue, Apaf-1, thereby triggering Apaf-1-mediated activation of caspase-9. Caspase-9 is thought to propagate the death signal by triggering other caspase activation events, the details of which remain obscure. Here, we report that six additional caspases (caspases-2, -3, -6, -7, -8, and -10) are processed in cell-free extracts in response to cytochrome c, and that three others (caspases-1, -4, and -5) failed to be activated under the same conditions. In vitro association assays confirmed that caspase-9 selectively bound to Apaf-1, whereas caspases-1, -2, -3, -6, -7, -8, and -10 did not. Depletion of caspase-9 from cell extracts abrogated cytochrome c-inducible activation of caspases-2, -3, -6, -7, -8, and -10, suggesting that caspase-9 is required for all of these downstream caspase activation events. Immunodepletion of caspases-3, -6, and -7 from cell extracts enabled us to order the sequence of caspase activation events downstream of caspase-9 and reveal the presence of a branched caspase cascade. Caspase-3 is required for the activation of four other caspases (-2, -6, -8, and -10) in this pathway and also participates in a feedback amplification loop involving caspase-9.
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85
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Bowen-Walker PL, Martin SJ, Gunn A. The transmission of deformed wing virus between honeybees (Apis mellifera L.) by the ectoparasitic mite varroa jacobsoni Oud. J Invertebr Pathol 1999; 73:101-6. [PMID: 9878295 DOI: 10.1006/jipa.1998.4807] [Citation(s) in RCA: 228] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Under field conditions, Varroa jacobsoni were shown to be highly effective vectors of deformed wing virus (DWV) between bees. Adult female mites obtained from honeybee pupae naturally infected with DWV contained virus titers many times in excess of those found in their hosts and, beyond that, which might be expected from a concentration effect. It is therefore possible that DWV may be capable of replicating within V. jacobsoni. Bees which tested positive for DWV exhibited characteristic morphological deformity and/or they died during pupation. Asymptomatic bees had much lower virus titers than those which were deformed or had died during pupation. It is therefore suggested that for DWV to cause pathology it must be present in pupae above a certain concentration. The amount of DWV vectored by V. jacobsoni will depend on the mites' level of infection, which will in turn depend on whether they had fed previously on dead or deformed bees and also on the rate of replication of the virus within the mites. Consequently, developing bees infested with large numbers of mites could suffer a high incidence of deformity if the mites are heavily infected or harbor an especially virulent strain of virus. A positive relationship was found between increasing numbers of mites on individual bees and the incidence of morphological deformity and death. This probably reflected the large number of viral particles transmitted by the mites, which resulted in many multiply infested bees dying before emergence. These results demonstrate the importance of the role of viruses when considering the pathology of V. jacobsoni and that much of the pathology previously associated with the effects of mite feeding could be attributed directly to secondary pathogens vectored by V. jacobsoni. Copyright 1999 Academic Press.
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Abstract
Field potential recordings were made from the dentate gyrus of urethane-anaesthetized rats in order to investigate the ability of 5 Hz stimulation to reverse long-term potentiation (LTP) induced by a high frequency tetanus. A 10 min train of 5 Hz was found to reverse LTP in a time-dependent fashion: as the interval between tetanus and 5 Hz was increased, LTP became progressively less susceptible to reversal. If 10 min or 30 min intervened between tetanization and 5 Hz stimulation, LTP was unaffected. These results indicate that dentate LTP in vivo exhibits a similar limited time window of vulnerability to reversal by low frequency stimulation to that previously reported in area CA1 in vitro.
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87
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Langiano T, Martin SJ. Quality improvement measures adopted by the Italian National Health Service. Int J Artif Organs 1998; 21:726-9. [PMID: 9894750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
The reform process underway within the Italian National Health System is aimed at making decision makers responsible for appropriate and efficient resource utilisation and at ensuring quality of care, eliminating conflict between fairness, quality and cost control. The risk for the quality of the services provided entailed by resource rationalisation is avoidable and controllable. This article explains how the Italian NHS has managed the reform process assuring quality improvement, and describes the policy and the tools adopted. As well as involving all players and the system as a whole in constant improvement, the Italian NHS's policy in pursuing quality of care is based on the adoption of a wide range of measures: measurement of health care and of clinical outcomes, systematic data collection, team work and protocols. The tools adopted, currently under implementation, to support quality control are: an integrated system of indicators for measuring efficiency and quality of NHS structures (demand and accessibility indicators, resource related indicators, activity indicators and result indicators); compulsory accreditation as a prerequisite for health care providers; a system to monitor and control the effects of the new prospective payment system; clinical guidelines (each related to a specific clinical problem); a menu of services (Carta dei Servizi) released by all NHS accredited service providers with full information and warranties regarding the services provided and their quality.
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Martin SJ, Pendland SL. Bactericidal activity and postantibiotic effect of clarithromycin and 14-hydroxyclarithromycin, alone and in combination, against Legionella pneumophila. J Antimicrob Chemother 1998; 41:643-8. [PMID: 9687103 DOI: 10.1093/jac/41.6.643] [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: 11/14/2022] Open
Abstract
Time-kill curves using simulated peak and trough serum concentrations, and postantibiotic effect (PAE) were determined for clarithromycin and 14-hydroxyclarithromycin alone and in combination against four strains of Legionella pneumophila. Both compounds were bactericidal at both peak and trough concentrations. The combination at trough concentrations demonstrated lower killing activity than the parent drug in three of the four strains. PAE ranges were 7.28-17.3 h for clarithromycin, 6.78-14.77 h for the metabolite, and 5.15-13.23 h for the combination.
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Amarante-Mendes GP, Finucane DM, Martin SJ, Cotter TG, Salvesen GS, Green DR. Anti-apoptotic oncogenes prevent caspase-dependent and independent commitment for cell death. Cell Death Differ 1998; 5:298-306. [PMID: 10200475 DOI: 10.1038/sj.cdd.4400354] [Citation(s) in RCA: 136] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Apoptosis is a morphologically defined type of cell death associated with the activation of certain proteases belonging to the ICE/CED-3 family, known as caspases. Resistance to apoptosis has been implicated as one of the mechanisms that participates in oncogenesis. We found that the broad-spectrum peptide inhibitor of the caspases, zVAD-fmk, interferes in a dose-dependent way with all the morphological and biochemical changes associated with apoptosis induced by anti-CD95 mAb, staurosporine, VP-16 and Act-D. However, with the exception of anti-CD95-triggered apoptosis, the insulted cells lost their clonogenic potential, even when pre-treated with a high dose of zVAD-fmk. Under these circumstances, the dying cells displayed no signs of apoptosis, including activation of caspases, externalization of phosphatidylserine, nuclear condensation, or DNA fragmentation. Instead, this cell death was characterized by cytoplasmic and nuclear vacuolization followed by the loss of plasma membrane integrity. Thus, preventing the onset of apoptosis by blocking caspase activity did not rescue cells from dying in response to drugs such as staurosporine, VP-16 and Act-D. In comparison, ectopic expression of anti-apoptotic oncogenes such as bcl-2 and bcr-abl not only inhibited apoptosis but also preserved the clonogenic potential of the cells. Therefore, oncogenesis is promoted not by simply interfering with caspase-mediated apoptosis, but by preventing an upstream event which we define as the commitment point for cell death.
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90
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Martin SJ, Meyer JM, Chuck SK, Jung R, Messick CR, Pendland SL. Levofloxacin and sparfloxacin: new quinolone antibiotics. Ann Pharmacother 1998; 32:320-36. [PMID: 9533064 DOI: 10.1345/aph.17178] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
OBJECTIVE To discuss the pharmacology, pharmacokinetics, spectrum of activity, clinical trials, and adverse effects of levofloxacin and sparfloxacin, two new fluoroquinolone antibiotics. DATA SOURCES Literature was identified by a MEDLINE search from January 1985 to September 1997. Abstracts and presentations were identified by review of program abstracts from the Interscience Conference on Antimicrobial Agents and Chemotherapy from 1988 to 1996. STUDY SELECTION Randomized, controlled clinical studies were selected for evaluation; however, uncontrolled studies were included when data were limited for indications approved by the Food and Drug Administration (FDA). In vitro data were selected from comparison trials whenever available. Only in vitro trials that provided data on the minimum inhibitory concentrations required to inhibit 90% of isolates were used. Data from North American studies were selected whenever available. DATA EXTRACTION Data were evaluated with respect to in vitro activity, study design, clinical and microbiologic outcomes, and adverse drug reactions. DATA SYNTHESIS Levofloxacin and sparfloxacin are active against pathogens frequently involved in community-acquired upper and lower respiratory tract infections, including Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, Mycoplasma pneumoniae, Legionella pneumophila, and Chlamydia pneumoniae. Both compounds have enhanced activity compared with ciprofloxacin against most gram-positive bacteria, including enterococci, streptococci, and staphylococci, and retain good activity against most Enterobacteriaceae and Pseudomonas aeruginosa. Sparfloxacin has greater anaerobic activity than levofloxacin, which is more active than ciprofloxacin or ofloxacin. Although many clinical studies are available only in abstract form, the clinical data demonstrate that these new quinolones are effective for most community-acquired upper and lower respiratory tract infections, urinary tract infections, gonococcal and nongonococcal urethritis, and skin and skin structure infections. FDA-approved indications are limited for both compounds to date. CONCLUSIONS Levofloxacin and sparfloxacin have improved gram-positive activity compared with that of older fluoroquinolones, and are administered once daily. Sparfloxacin-associated photosensitivity may limit its therapeutic usefulness. Clinical trials confirm that these agents are as effective as traditional therapies for the management of community-acquired pneumonia, acute exacerbations of chronic bronchitis, sinusitis, urinary tract infections, acute gonococcal and nongonococcal urethritis, and skin and skin structure infections.
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Abstract
Tumour necrosis factor (TNF) is an inflammatory cytokine possessing a unique property: it can induce cells to undergo apoptosis. The sensitivity of different cell types to TNF-induced apoptosis can vary dramatically, but most cells become very sensitive upon simultaneous treatment with inhibitors of protein synthesis. It has been suggested therefore that a gene, or set of genes, is induced upon TNF receptor activation that downregulates the apoptosis signal. Recent results have shown that NF-kappa B, a transcription factor activated upon TNF signalling, is at least partly responsible for this effect. These findings have broadened the role of NF-kappa B from that of a regulator of immune and inflammatory responses to include an involvement in the regulation of apoptosis.
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92
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Heunisch C, Resnick DJ, Vitello JM, Martin SJ. Conjugated estrogens for the management of gastrointestinal bleeding secondary to uremia of acute renal failure. Pharmacotherapy 1998; 18:210-7. [PMID: 9469696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Bleeding commonly occurs secondary to the uremia of acute and chronic renal failure. Hemodialysis is indicated for the management of uremic bleeding, and administration of red blood cells and cryoprecipitate is also helpful. Desmopressin successfully reduces the bleeding tendency in patients with chronic renal failure for short-term operations or procedures, but the frequency of tachyphylaxis is high and limits the drug's usefulness for major bleeds. Conjugated estrogens shorten bleeding times in uremia and may provide a more sustained hemostatic effect over desmopressin. A patient with acute renal failure and uncontrolled gastrointestinal bleeding was successfully treated with conjugated estrogens after failing desmopressin and octreotide therapy.
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93
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Pendland SL, Martin SJ, Chen C, Schreckenberger PC, Danziger LH. Comparison of charcoal- and starch-based media for testing susceptibilities of Legionella species to macrolides, azalides, and fluoroquinolones. J Clin Microbiol 1997; 35:3004-6. [PMID: 9350781 PMCID: PMC230109 DOI: 10.1128/jcm.35.11.3004-3006.1997] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
We compared growth characteristics of 46 Legionella strains grown on buffered charcoal yeast extract alpha (BCYE alpha) agar and buffered starch yeast extract (BSYE) agar and MICs of macrolides, azalides, and fluoroquinolones for these organisms. Growth was poor and not reproducible on BSYE agar. Growth was excellent on BCYE alpha, and MICs were easy to interpret. BCYE alpha is superior to BSYE for testing susceptibilities of Legionella species by agar dilution.
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94
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Martin SJ, Pendland SL, Chen C, Schreckenberger PC, Danziger LH. In vitro activity of clarithromycin alone and in combination with ciprofloxacin or levofloxacin against Legionella spp.: enhanced effect by the addition of the metabolite 14-hydroxy clarithromycin. Diagn Microbiol Infect Dis 1997; 29:167-71. [PMID: 9401809 DOI: 10.1016/s0732-8893(97)81806-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Clarithromycin is metabolized to an active metabolite, 14-hydroxy clarithromycin. These compounds have demonstrated excellent in vitro activity against Legionella species, with both agents having significantly lower MICs than erythromycin. Using a checkerboard assay, the activity of clarithromycin and its hydroxy metabolite, alone and in combination, was examined against 41 Legionella organisms. The activity of clarithromycin and 14-hydroxy clarithromycin, in a 2:1 ratio, plus ciprofloxacin or levofloxacin was also determined. Activity of the antibiotic combinations was determined by calculating the fractional inhibitory concentration index. An agar dilution method using buffered charcoal yeast extract media was used for susceptibility and synergy testing. An inoculum of 10(4) CFU/spot was used, with all plates incubated at 35 degrees C for 48 h. The MIC90 for clarithromycin or 14-hydroxy clarithromycin alone was 0.5, versus 0.25 microgram/mL for the combination. Additive effects were observed with clarithromycin and its hydroxy metabolite for 61% of the Legionella species, with fractional inhibitory concentration indices ranging from 0.63 to 1.25. The 14-hydroxy metabolite significantly increased the activity of both fluoroquinolone/clarithromycin combinations. Based on these data, in vitro susceptibility testing of agents such as clarithromycin should be reevaluated to account for the activity of active metabolites.
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95
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Martin SJ, Morris RG. (R,S)-alpha-methyl-4-carboxyphenylglycine (MCPG) fails to block long-term potentiation under urethane anaesthesia in vivo. Neuropharmacology 1997; 36:1339-54. [PMID: 9423922 DOI: 10.1016/s0028-3908(97)00129-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The effects of the metabotropic glutamate receptor antagonist (R,S)-alpha-methyl-4-carboxyphenylglycine (MCPG) on the induction of long-term potentiation (LTP) in the dentate gyrus were examined under urethane anaesthesia in vivo. In experiment 1, bilateral intraventricular infusion of either 20 mM or 200 mM (R,S)-MCPG (5 microl each side) failed to block LTP in the perforant path-granule cell projection, relative to vehicle-infused controls; 30 mM D-AP5 (5 microl each side) infused in the same way as MCPG completely blocked LTP. Experiment 2, in which the contralateral perforant path-dentate gyrus pathway was used as a non-tetanized control, revealed that slight baseline changes induced by MCPG infusion were transient; again no block of LTP was obtained. The efficacy of mGluR blockade was confirmed in experiment 3, in which MCPG antagonized an increase in spontaneous activity induced by (1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid (ACPD). In experiment 4, significant depotentiation was induced by low frequency stimulation (5 Hz for 1 min) given 2 min after high frequency tetanization, but MCPG remained ineffective in blocking LTP after a second tetanus. In experiment 5, increasing the period of low frequency stimulation from 1 to 10 min produced greater depotentiation, but still did not unmask an MCPG-sensitive component of LTP. These experiments fail to support a role for mGluRs in the induction of LTP in the dentate gyrus under urethane anaesthesia in vivo, nor do they support the idea that a metabotropic switch controlling sensitivity to MCPG is reset by depotentiation.
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96
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Ellerby HM, Martin SJ, Ellerby LM, Naiem SS, Rabizadeh S, Salvesen GS, Casiano CA, Cashman NR, Green DR, Bredesen DE. Establishment of a cell-free system of neuronal apoptosis: comparison of premitochondrial, mitochondrial, and postmitochondrial phases. J Neurosci 1997; 17:6165-78. [PMID: 9236228 PMCID: PMC3913837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Apoptosis is a fundamental process required for normal development of the nervous system and is triggered during neurodegenerative disease. To dissect the molecular events leading to neuronal cell death, we have developed a cell-free model of neuronal apoptosis. The model faithfully reproduces key elements of apoptosis, including chromatin condensation, DNA fragmentation, caspase activation/processing, and selective substrate cleavage. We report that cell-free apoptosis is activated in premitochondrial, mitochondrial, and postmitochondrial phases by tamoxifen, mastoparan, and cytochrome c, respectively, allowing a functional ordering of these proapoptotic modulators. Furthermore, this is the first report of mitochondrial-mediated activation of cell-free apoptosis in a cell extract. Although Bcl-2 blocks activation at the premitochondrial and mitochondrial levels, it does not affect the postmitochondrial level. The cell-free system described here provides a valuable tool to elucidate the molecular events leading to neuronal cell death.
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97
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Kluck RM, Martin SJ, Hoffman BM, Zhou JS, Green DR, Newmeyer DD. Cytochrome c activation of CPP32-like proteolysis plays a critical role in a Xenopus cell-free apoptosis system. EMBO J 1997; 16:4639-49. [PMID: 9303308 PMCID: PMC1170090 DOI: 10.1093/emboj/16.15.4639] [Citation(s) in RCA: 313] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
In a cell-free system based on Xenopus egg extracts, Bcl-2 blocks apoptotic activity by preventing cytochrome c release from mitochondria. We now describe in detail the crucial role of cytochrome c in this system. The mitochondrial fraction, when incubated with cytosol, releases cytochrome c. Cytochrome c in turn induces the activation of protease(s) resembling caspase-3 (CPP32), leading to downstream apoptotic events, including the cleavage of fodrin and lamin B1. CPP32-like protease activity plays an essential role in this system, as the caspase inhibitor, Ac-DEVD-CHO, strongly inhibited fodrin and lamin B1 cleavage, as well as nuclear morphology changes. Cytochrome c preparations from various vertebrate species, but not from Saccharomyces cerevisiae, were able to initiate all signs of apoptosis. Cytochrome c by itself was unable to process the precursor form of CPP32; the presence of cytosol was required. The electron transport activity of cytochrome c is not required for its pro-apoptotic function, as Cu- and Zn-substituted cytochrome c had strong pro-apoptotic activity, despite being redox-inactive. However, certain structural features of the molecule were required for this activity. Thus, in the Xenopus cell-free system, cytosol-dependent mitochondrial release of cytochrome c induces apoptosis by activating CPP32-like caspases, via unknown cytosolic factors.
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98
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Martin SJ, Audrain MA, Oksman F, Ecoiffier M, Attal M, Milpied N, Esnault VL. Antineutrophil cytoplasmic antibodies (ANCA) in chronic graft-versus-host disease after allogeneic bone marrow transplantation. Bone Marrow Transplant 1997; 20:45-8. [PMID: 9232255 DOI: 10.1038/sj.bmt.1700828] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We studied the usefulness of monitoring antineutrophil cytoplasmic antibodies (ANCA) in chronic graft-versus-host disease (cGVHD), a major complication of allogeneic bone marrow transplantation. Antigen-specific ELISA and indirect immunofluorescence (IIF) were used to search for ANCA in 47 allogeneic bone marrow graft recipients who developed cGVHD and in 43 who did not (controls). Eight patients exhibited ANCA IIF positivity in the cGVHD group, but none in the controls. Specificity was confirmed in antigen-specific assays in only two cGVHD patients, both showing antilactoferrin (anti-LF) activity. One of these patients was followed-up, and the antilactoferrin antibodies were found only at the time of active but limited cGVHD. Among three ANCA IIF-positive patients, two had antinuclear autoantibodies and three antineutrophil alloantibodies secondary to blood transfusion, which may have been responsible for false ANCA IIF positivity. It is concluded that ANCA determination is not useful in patients with cGVHD. Polyclonal activation of B lymphocytes could result in ANCA activity during cGVHD. False-positive ANCA could be due to allo-immunization following blood transfusion. Rare patients may present antilactoferrin antibodies of unknown clinical significance.
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Tan X, Martin SJ, Green DR, Wang JY. Degradation of retinoblastoma protein in tumor necrosis factor- and CD95-induced cell death. J Biol Chem 1997; 272:9613-6. [PMID: 9092486 DOI: 10.1074/jbc.272.15.9613] [Citation(s) in RCA: 135] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The product of the retinoblastoma susceptibility gene, RB, is a negative regulator of cell proliferation. Inactivation of RB does not interfere with embryonic growth or differentiation. However, Rb-deficient embryos show abnormal degeneration of neurons and lens fiber cells through apoptosis, suggesting that RB may protect against programmed cell death. Consistent with this notion, RB is found to be degraded in tumor necrosis factor (TNF)- and CD95-induced death. A consensus caspase cleavage site at the C terminus of RB is cleaved in vitro and in vivo by proteases related to CPP32 (caspase 3). Mutation of the consensus cleavage site generates a cleavage-resistant RB which is not degraded during cell death. Expression of this non-degradable RB is found to antagonize the cytotoxic effects of TNF in Rb-/- 3T3 cells, but this mutant RB cannot attenuate the rapid death induced by anti-CD95 in Jurkat/T cells. These results show that RB is a target of the caspase family of proteases during cell death and suggest that the failure to degrade RB can attenuate the death response toward some but not all death inducers.
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100
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Martin SJ, Audrain MA, Baranger T, Moreau A, Dantal J, Testa A, Esnault VL. Recurrence of immunoglobulin A nephropathy with immunoglobulin A antineutrophil cytoplasmic antibodies following renal transplantation. Am J Kidney Dis 1997; 29:125-31. [PMID: 9002541 DOI: 10.1016/s0272-6386(97)90019-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We previously reported the presence of immunoglobulin A (IgA) antineutrophil cytoplasmic antibodies (ANCAs) in patients presenting IgA nephropathy (IgAN), particularly when associated with Henoch-Schonlein purpura. Most of the patients exhibited IgA ANCAs directed at an unknown 50-kd neutrophil protein but no IgG ANCAs. A subgroup of patients presented IgG as well as IgA ANCAs, suggesting an overlap syndrome between Henoch-Schonlein purpura and microscopic polyangiitis. We aimed at confirming the correlation of IgA ANCA titer with disease activity in a patient presenting IgAN relapse following kidney transplantation. The ANCAs were searched for by isotype- and antigen-specific enzyme-linked immunosorbent assay. Specificity was confirmed by antigen-specific enzyme-linked immunosorbent assay and Western blot analysis. At the onset of the disease in 1989, the patient presented with ANCAs of IgA and IgG class with specificity for myeloperoxidase and no rheumatoid factor. End-stage renal failure developed 1 year afterward. In 1991, he received a cadaveric renal allograft, and 9 months later developed acute nephrotic syndrome with rapidly progressive renal failure and recurrence of IgAN on the kidney transplant. An increase in IgA but not IgG ANCAs was found on clinical relapse after kidney transplantation. We conclude that rare patients may present an overlap syndrome between IgG ANCA-positive systemic vasculitis and IgAN, characterized by the presence of IgG and IgA anti-myeloperoxidase antibodies.
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