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Llada IM, Mote RS, Hill NS, Lourenco JM, Jones DP, Suen G, Ross MK, Filipov NM. Ruminal ergovaline and volatile fatty acid dynamics: Association with poor performance and a key growth regulator in steers grazing toxic tall fescue. Environ Toxicol Pharmacol 2024; 105:104354. [PMID: 38151218 DOI: 10.1016/j.etap.2023.104354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 12/22/2023] [Indexed: 12/29/2023]
Abstract
Fescue toxicosis (FT) is produced by an ergot alkaloid (i.e., ergovaline [EV])-producing fungus residing in toxic fescue plants. Associations between EV, decreased weight gain and ruminal volatile fatty acids are unclear. Feces, rumen fluid, and blood were collected from 12 steers that grazed non-toxic (NT) or toxic (E +) fescue for 28 days. The E + group exhibited decreased propionate (P), increased acetate (A), and increased ruminal A:P ratio, with similar trends in feces. Plasma GASP-1 (G-Protein-Coupled-Receptor-Associated-Sorting-Protein), a myostatin inhibitor, decreased (day 14) only in E + steers. Ergovaline was present only in E + ruminal fluid and peaked on day 14. The lower ruminal propionate and higher A:P ratio might contribute to FT while reduced GASP-1 might be a new mechanism linked to E + -related weight gain reduction. Day 14 ergovaline zenith likely reflects ruminal adaptations favoring EV breakdown and its presence only in rumen points to local, rather than systemic effects.
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Affiliation(s)
- I M Llada
- Interdisciplinary Toxicology Program, United States; Department of Physiology and Pharmacology, United States
| | - R S Mote
- Interdisciplinary Toxicology Program, United States; Department of Physiology and Pharmacology, United States
| | - N S Hill
- Department of Crop and Soil Sciences, United States
| | - J M Lourenco
- Department of Animal and Dairy Sciences, University of Georgia, Athens, GA, United States
| | - D P Jones
- Department of Medicine, Division of Pulmonary, Allergy, and Critical Care Medicine, Emory University, Atlanta, GA, United States
| | - G Suen
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, United States
| | - M K Ross
- Center for Environmental Health Sciences, Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States
| | - N M Filipov
- Interdisciplinary Toxicology Program, United States; Department of Physiology and Pharmacology, United States.
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Neujahr DC, Uppal K, Force SD, Fernandez F, Lawrence C, Pickens A, Bag R, Lockard C, Kirk AD, Tran V, Lee K, Jones DP, Park Y. Bile acid aspiration associated with lung chemical profile linked to other biomarkers of injury after lung transplantation. Am J Transplant 2014; 14:841-8. [PMID: 24666830 PMCID: PMC5505513 DOI: 10.1111/ajt.12631] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Revised: 12/12/2013] [Accepted: 12/13/2013] [Indexed: 01/25/2023]
Abstract
Aspiration of gastrointestinal contents has been linked to worse outcomes following lung transplantation but uncertainty exists about underlying mechanisms. We applied high-resolution metabolomics of bronchoalveolar lavage fluid (BALF) in patients with episodic aspiration (defined by bile acids in the BALF) to identify potential metabolic changes associated with aspiration. Paired samples, one with bile acids and another without, from 29 stable lung transplant patients were studied. Liquid chromatography coupled to high-resolution mass spectroscopy was used to interrogate metabolomic contents of these samples. Data were obtained for 7068 ions representing intermediary metabolites, environmental agents and chemicals associated with microbial colonization. A substantial number (2302) differed between bile acid positive and negative samples when analyzed by false discovery rate at q = 0.01. These included pathways associated with microbial metabolism. Hierarchical cluster analysis defined clusters of chemicals associated with bile acid aspiration that were correlated to previously reported biomarkers of lung injury including T cell granzyme B level and the chemoattractants CXCL9 and CXCL10. These data specifically link bile acids presence in lung allografts to inflammatory pathways known to segregate with worsening allograft outcome, and provide additional mechanistic insight into the association between reflux and lung allograft injury.
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Affiliation(s)
- D. C. Neujahr
- Emory Transplant Center, Emory University, Atlanta, GA,Corresponding author: David C. Neujahr,
| | - K. Uppal
- Clinical Biomarkers Laboratory Medicine, Emory University, Atlanta, GA
| | - S. D. Force
- Emory Transplant Center, Emory University, Atlanta, GA
| | - F. Fernandez
- Emory Transplant Center, Emory University, Atlanta, GA
| | - C. Lawrence
- Emory Transplant Center, Emory University, Atlanta, GA
| | - A. Pickens
- Emory Transplant Center, Emory University, Atlanta, GA
| | - R. Bag
- Emory Transplant Center, Emory University, Atlanta, GA
| | - C. Lockard
- Emory Transplant Center, Emory University, Atlanta, GA
| | - A. D. Kirk
- Emory Transplant Center, Emory University, Atlanta, GA
| | - V. Tran
- Clinical Biomarkers Laboratory Medicine, Emory University, Atlanta, GA
| | - K. Lee
- Department of Industrial Engineering, Hanyang University, Hanyang, Korea
| | - D. P. Jones
- Clinical Biomarkers Laboratory Medicine, Emory University, Atlanta, GA
| | - Y. Park
- Clinical Biomarkers Laboratory Medicine, Emory University, Atlanta, GA,College of Pharmacy, Korea University, Sejong City, Korea
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Abstract
Living systems have three major types of cell signalling systems that are dependent upon high-energy chemicals, redox environment and transmembranal ion-gating mechanisms. Development of integrated systems biology descriptions of cell signalling require conceptual models incorporating all three. Recent advances in redox biology show that thiol-disulphide redox systems are regulated under dynamic, nonequilibrium conditions, progressively oxidized with the life cycle of cells and distinct in terms of redox potentials amongst subcellular compartments. This article uses these observations as a basis to distinguish 'redox-sensing' mechanisms, which are more global biologic redox control mechanisms, from 'redox signalling', which involves conveyance of discrete activating or inactivating signals. Both redox sensing and redox signalling use sulphur switches, especially cysteine (Cys) residues in proteins which are sensitive to reversible oxidation, nitrosylation, glutathionylation, acylation, sulfhydration or metal binding. Unlike specific signalling mechanisms, the redox-sensing mechanisms provide means to globally affect the rates and activities of the high-energy, ion-gating and redox-signalling systems by controlling sensitivity, distribution, macromolecular interactions and mobility of signalling proteins. Effects mediated through Cys residues not directly involved in signalling means redox-sensing control can be orthogonal to the signalling mechanisms. This provides a capability to integrate signals according to cell cycle and physiologic state without fundamentally altering the signalling mechanisms. Recent findings that thiol-disulphide pools in humans are oxidized with age, environmental exposures and disease risk suggest that redox-sensing thiols could provide a central mechanistic link in disease development and progression.
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Affiliation(s)
- D P Jones
- Department of Medicine, Emory University, Atlanta, GA 30322, USA.
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Abstract
Mammalian cells are highly organized to optimize function. For instance, oxidative energy-producing processes in mitochondria are sequestered away from plasma membrane redox signalling complexes and also from nuclear DNA, which is subject to oxidant-induced mutation. Proteins are unique among macromolecules in having reversible oxidizable elements, 'sulphur switches', which support dynamic regulation of structure and function. Accumulating evidence shows that redox signalling and control systems are maintained under kinetically limited steady states, which are highly displaced from redox equilibrium and distinct among organelles. Mitochondria are most reducing and susceptible to oxidation under stressed conditions, while nuclei are also reducing but relatively resistant to oxidation. Within compartments, the glutathione and thioredoxin systems serve parallel and non-redundant functions to maintain the dynamic redox balance of subsets of protein cysteines, which function in redox signalling and control. This organization allows cells to be poised to respond to cell stress but also creates sites of vulnerability. Importantly, disruption of redox organization is a common basis for disease. Research tools are becoming available to elucidate details of subcellular redox organization, and this development highlights an opportunity for a new generation of targeted antioxidants to enhance and restore redox signalling and control in disease prevention.
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Affiliation(s)
- D P Jones
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, Emory University, Atlanta, GA 30322, USA.
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Porkert M, Sher S, Reddy U, Cheema F, Niessner C, Kolm P, Jones DP, Hooper C, Taylor WR, Harrison D, Quyyumi AA. Tetrahydrobiopterin: a novel antihypertensive therapy. J Hum Hypertens 2008; 22:401-7. [PMID: 18322548 DOI: 10.1038/sj.jhh.1002329] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2007] [Revised: 11/21/2007] [Accepted: 12/01/2007] [Indexed: 11/09/2022]
Abstract
Tetrahydrobiopterin (BH(4)) is a cofactor for the nitric oxide (NO) synthase enzymes, such that its insufficiency results in uncoupling of the enzyme, leading to release of superoxide rather than NO in disease states, including hypertension. We hypothesized that oral BH(4) will reduce arterial blood pressure (BP) and improve endothelial function in hypertensive subjects. Oral BH(4) was given to subjects with poorly controlled hypertension (BP >135/85 mm Hg) and weekly measurements of BP and endothelial function made. In Study 1, 5 or 10 mg kg(-1) day(-1) of BH(4) (n=8) was administered orally for 8 weeks, and in Study 2, 200 and 400 mg of BH(4) (n=16) was given in divided doses for 4 weeks. Study 1: significant reductions in systolic (P=0.005) and mean BP (P=0.01) were observed with both doses of BH(4). Systolic BP was 15+/-15 mm Hg (P=0.04) lower after 5 weeks and persisted for the 8-week study period. Study 2: subjects given 400 mg BH(4) had decreased systolic (P=0.03) and mean BP (P=0.04), with a peak decline of 16+/-19 mm Hg (P=0.04) at 3 weeks. BP returned to baseline 4 weeks after discontinuation. Significant improvement in endothelial function was observed in Study 1 subjects and those receiving 400 mg BH(4). There was no significant change in subjects given the 200 mg dose. This pilot investigation indicates that oral BH(4) at a daily dose of 400 mg or higher has a significant and sustained antihypertensive effect in subjects with poorly controlled hypertension, an effect that is associated with improved endothelial NO bioavailability.
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Affiliation(s)
- M Porkert
- Division of Cardiology, Emory University, Atlanta, GA, USA
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Affiliation(s)
- D. P. Jones
- a Cavendish Laboratory , Madingley Road, Cambridge , England
| | - N. Thomas
- a Cavendish Laboratory , Madingley Road, Cambridge , England
| | - W. A. Phillips
- a Cavendish Laboratory , Madingley Road, Cambridge , England
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Kyriacou PA, Crerar-Gilber A, Langford RM, Jones DP. Electro-optical techniques for the investigation of photoplethysmographic signals in human abdominal organs. ACTA ACUST UNITED AC 2006. [DOI: 10.1088/1742-6596/45/1/033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Shafqat K, Jones DP, Langford RM, Kyriacou PA. Filtering techniques for the removal of ventilator artefact in oesophageal pulse oximetry. Med Biol Eng Comput 2006; 44:729-37. [PMID: 16937215 DOI: 10.1007/s11517-006-0089-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2005] [Accepted: 06/25/2006] [Indexed: 10/24/2022]
Abstract
The oesophagus has been shown to be a reliable site for monitoring blood oxygen saturation (SpO(2)). However, the photoplethysmographic (PPG) signals from the lower oesophagus are frequently contaminated by a ventilator artefact making the estimation of SpO(2) impossible. A 776th order finite impulse response (FIR) filter and a 695th order interpolated finite impulse response (IFIR) filter were implemented to suppress the artefact. Both filters attenuated the ventilator artefact satisfactorily without distorting the morphology of the PPG when processing recorded data from ten cardiopulmonary bypass patients. The IFIR filter was the better since it conformed more closely to the desired filter specifications and allowed real-time processing. The average improvements in signal-to-noise ratio (SNR) achieved by the FIR and IFIR filters for the fundamental component of the red PPG signals with respect to the fundamental component of the artefact were 57.96 and 60.60 dB, respectively. The corresponding average improvements achieved by the FIR and IFIR filters for the infrared PPG signals were 54.83 and 60.96 dB, respectively. Both filters were also compared with their equivalent tenth order Butterworth filters. The average SNR improvements for the FIR and IFIR filters were significantly higher than those for the Butterworth filters.
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Affiliation(s)
- K Shafqat
- School of Engineering and Mathematical Sciences, City University, London, ECIV 0HB, UK
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Abstract
Taurine transport undergoes an adaptive response to changes in taurine availability. Unlike most amino acids, taurine is not metabolized or incorporated into protein but remains free in the intracellular water. Most amino acids are reabsorbed at rates of 98-99%, but reabsorption of taurine may range from 40% to 99.5%. Factors that influence taurine accumulation include ionic environment, electrochemical charge, and post-translational and transcriptional factors. Among these are protein kinase C (PKC) activation and transactivation or repression by proto-oncogenes such as WT1, c-Jun, c-Myb and p53. Renal adaptive regulation of the taurine transporter (TauT) was studied in vivo and in vitro. Site-directed mutagenesis and the oocyte expression system were used to study post-translational regulation of the TauT by PKC. Reporter genes and Northern and Western blots were used to study transcriptional regulation of the taurine transporter gene (TauT). We demonstrated that (i) the body pool of taurine is controlled through renal adaptive regulation of TauT in response to taurine availability; (ii) ionic environment, electrochemical charge, pH, and developmental ontogeny influence renal taurine accumulation; (iii) the fourth segment of TauT is involved in the gating of taurine across the cell membrane, which is controlled by PKC phosphorylation of serine 322 at the post-translational level; (iv) expression of TauT is repressed by the p53 tumour suppressor gene and is transactivated by proto-oncogenes such as WT1, c-Jun, and c-Myb; and (v) over-expression of TauT protects renal cells from cisplatin-induced nephrotoxicity.
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Affiliation(s)
- X Han
- Department of Pediatrics, The University of Tennessee Health Science Center, Memphis, TN 38103, USA
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Pal SK, Kyriacou PA, Kumaran S, Fadheel S, Emamdee R, Langford RM, Jones DP. Evaluation of oesophageal reflectance pulse oximetry in major burns patients. Burns 2005; 31:337-41. [PMID: 15774290 DOI: 10.1016/j.burns.2004.10.025] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2004] [Accepted: 10/05/2004] [Indexed: 11/17/2022]
Abstract
Pulse oximetry is being used in everyday clinical practice in anaesthesia utilising a peripheral probe. However, it may be unreliable in certain clinical situations such as hypothermia, hypovolemia, vasoconstriction and decreased cardiac output. Similar situations occur in burns patients and, more importantly, burns to extremities which limit the sites available for measurement of peripheral oxygen saturation (SpO(2)). To overcome these limitations, the oesophagus has been investigated as an alternative measurement site, as perfusion may be preferentially preserved centrally. A miniaturised reflectance oesophageal saturation (SpO(2)) probe has been constructed utilising infrared and red photodiodes and a photodetector. Our study was aimed at evaluating the reliability of oesophageal pulse oximetry in major burns patients. Seven adult patients (five males, two females) were studied. They were sedated and ventilated as part of their routine care. Measurable photoplethysmographic (PPG) traces and SpO(2) values were obtained in the oesophagus of all patients at a mean depth of 15.6+/-1.8 cm (measured from the lips). It was found that the oesophageal pulse oximeter results were in good agreement with oxygen saturation measurements obtained by a CO-oximeter. The mean (+/-S.D.) of the differences between the oesophageal oxygen saturation results and those from CO-oximetry was 0.50+/-0.69%. A Bland and Altman analysis showed that the bias and the limits of agreement between the oesophageal and commercial toe pulse oximeters were 0.4% and -3.6% to 4.6%, respectively. This study suggests that the oesophagus can be used as an alternative site for monitoring arterial blood oxygen saturation by pulse oximetry in burned patients.
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Affiliation(s)
- S K Pal
- St. Andrew's Centre for Plastic Surgery and Burns, Broomfield Hospital, Chelmsford, Essex CM17ET, UK.
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Alteheld B, Evans ME, Gu LH, Ganapathy V, Leibach FH, Jones DP, Ziegler TR. Alanylglutamine dipeptide and growth hormone maintain PepT1-mediated transport in oxidatively stressed Caco-2 cells. J Nutr 2005; 135:19-26. [PMID: 15623827 DOI: 10.1093/jn/135.1.19] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Reactive oxygen species (ROS) produced by gut mucosal cells during conditions such as inflammatory bowel disease (IBD) may impair mucosal repair and nutrient transport/absorptive function. Absorption of di- and tripeptides in the small intestine and colon is mediated by the H(+)-dependent transporter PepT1, but effects of oxidative stress on di- and tripeptide transport are unknown. We assessed whether exposure to hydrogen peroxide (H(2)O(2)) influences dipeptide transport in human colonic epithelial (Caco-2) cells. Uptake of [(14)C]glycylsarcosine (Gly-Sar) was used to evaluate PepT1-mediated dipeptide transport. Exposure to 1-5 mmol/L H(2)O(2) for 24 h caused a dose-dependent decrease in Gly-Sar transport, which was associated with decreased PepT1 transport velocity (V(max)). Treatment with alanylglutamine (Ala-Gln) or growth hormone (GH) did not alter Caco-2 Gly-Sar transport in the absence of H(2)O(2). However, both Ala-Gln and GH prevented the decrease in dipeptide transport observed with 1 mmol/L H(2)O(2) treatment. Ala-Gln, but not GH, maintained cellular glutathione and prevented the decrease in PepT1 protein expression. Thus, these agents should be further investigated as potential therapies to improve absorption of small peptides in disorders associated with oxidative injury to the gut mucosa.
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Affiliation(s)
- B Alteheld
- Department of Nutrition Science, University of Bonn, Germany
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14
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Abstract
Pulse oximetry probes placed peripherally may fail to give accurate values of blood oxygen saturation when the peripheral circulation is poor. Because central blood flow may be preferentially preserved, we investigated the oesophagus as an alternative monitoring site. A reflectance blood oxygen saturation probe was developed and evaluated in 49 patients undergoing cardiothoracic surgery. The oesophageal pulse oximeter results were in good agreement with oxygen saturation measurements obtained by a blood gas analyser, a CO-oximeter and a commercial finger pulse oximeter. The median (IQR [range]) difference between the oesophageal oxygen saturation results and those from blood gas analysis were 0.00 (-0.30 to 0.30 [-4.47 to 2.60]), and between the oesophageal oxygen saturation results and those from CO-oximetry were 0.75 (0.30 to 1.20 [-1.80 to 1.80]). Bland-Altman analysis showed that the bias and the limits of agreement between the oesophageal and finger pulse oximeters were -0.3% and -3.3 to 2.7%, respectively. In five (10.2%) patients, the finger pulse oximeter failed for at least 10 min, whereas the oesophageal readings remained reliable. The results suggest that the oesophagus may be used as an alternative monitoring site for pulse oximetry even in patients with compromised peripheral perfusion.
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Affiliation(s)
- P A Kyriacou
- Medical Electronics & Physics, Department of Engineering, Queen Mary, University of London, London E1 NS, UK.
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Kyriacou PA, Powell S, Langford RM, Jones DP. Investigation of oesophageal photoplethysmographic signals and blood oxygen saturation measurements in cardiothoracic surgery patients. Physiol Meas 2002; 23:533-45. [PMID: 12214761 DOI: 10.1088/0967-3334/23/3/305] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Pulse oximeter probes attached to the finger may fail to estimate blood oxygen saturation (SpO2) in patients with compromised peripheral perfusion (e.g. hypothermic cardiopulmonary bypass surgery). The measurement of SpO2 from a central organ such as the oesophagus is suggested as an alternative to overcome this problem. A reflectance oesophageal pulse oximeter probe and a processing system implemented in LabVIEW were developed. The system was evaluated in clinical measurements on 50 cardiothoracic surgery patients. Oesophageal photoplethysmographic (PPG) signals with large amplitudes and high signal-to-noise ratios were measured from various depths within the oesophagus from all the cardiothoracic patients. The oesophageal PPG amplitudes from these patients were in good agreement with previous oesophageal PPG amplitude measurements from healthy anaesthetized patients. The oesophageal pulse oximeter SpO2 results agreed well with the estimated arterial oxygen saturation (SaO2) values inferred from the oxygen tension obtained by blood gas analysis. The mean (+/- SD) of the differences between the oesophageal pulse oximeter SpO2 readings and those from blood gas analysis was 0.02 +/- 0.88%. Also, the oesophageal pulse oximeter was found to be reliable and accurate in five cases of poor peripheral perfusion when a commercial finger pulse oximeter probe failed to estimate oxygen saturation values for at least 10 min. These results suggest that the arterial blood circulation to the oesophagus is less subject to vasoconstriction and decreased PPG amplitudes than are the peripheral sites used for pulse oximetry such as the finger. It is concluded that oesophageal SPO2 monitoring may be of clinical value.
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Affiliation(s)
- P A Kyriacou
- Department of Engineering, Queen Mary, University of London, UK.
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Crerar-Gilbert AJ, Kyriacou PA, Jones DP, Langford RM. Assessment of photoplethysmographic signals for the determination of splanchnic oxygen saturation in humans. Anaesthesia 2002; 57:442-5. [PMID: 11966553 DOI: 10.1046/j.0003-2409.2001.02453.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The need for a clinically applicable method of detecting splanchnic hypoxia has led to experimental animal studies which indicated the usefulness of intestinal pulse oximetry. Pulse oximetry relies on detection of photoplethysmographic signals. Before developing a pulse oximeter for the measurement of organ oxygen saturation peri-operatively, we designed a system based on a reflectance photoplethysmographic probe to investigate photoplethysmographic signals from human viscera (bowel, liver, and kidney). Recordings were obtained simultaneously from the abdominal viscera and the finger using identical probes. The probe was held sequentially for up to 2 min on the surface of viscera of 12 patients during routine laparotomy. Measurable splanchnic photoplethysmographic signals were recorded for the first time in humans. There were no statistically significant differences between photoplethysmographic amplitudes from viscera and those from the finger. Our results indicate the feasibility of pulse oximetry for the measurement of visceral oxygenation in humans.
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Affiliation(s)
- A J Crerar-Gilbert
- Anaesthetics Laboratory, St Bartholomew's Hospital, Barts and the London NHS Trust, London EC1A 7BE, UK
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Armstrong JS, Hornung B, Lecane P, Jones DP, Knox SJ. Rotenone-induced G2/M cell cycle arrest and apoptosis in a human B lymphoma cell line PW. Biochem Biophys Res Commun 2001; 289:973-8. [PMID: 11741286 DOI: 10.1006/bbrc.2001.6054] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Concentrations of rotenone (ROT) that block electron flow through mitochondrial complex I (100 nM) did not significantly alter either cell viability or the growth of PW cells. However, 10- to 50-fold higher concentrations (1-5 microM) were found to induce a dose-dependent cell cycle arrest predominantly at the G2/M stage of the cycle and apoptosis. Apoptosis was dependent on the cell cycle arrest, since apoptosis but not the G2/M arrest was prevented with the broad spectrum caspase inhibitor zVADfmk. Biochemical features of apoptosis included mitochondrial cytochrome c release, reactive oxygen species generation, and the activation of procaspase 3. Thus, ROT inhibition of mitochondrial electron transport may be insufficient to induce apoptosis in PW cells. Instead, apoptosis in these cells occurs as a consequence of disruption of the cell cycle and is only indirectly dependent upon mitochondrial electron transport.
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Affiliation(s)
- J S Armstrong
- Department of Radiation Oncology, Stanford University Medical Center, Stanford, California 94305-5105, USA.
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Bytnerowicz A, Padgett PE, Arbaugh MJ, Parker DR, Jones DP. Passive sampler for measurements of atmospheric nitric acid vapor (HNO3) concentrations. ScientificWorldJournal 2001; 1:815-22. [PMID: 12805717 PMCID: PMC6084133 DOI: 10.1100/tsw.2001.323] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Nitric acid (HNO3) vapor is an important nitrogenous air pollutant responsible for increasing saturation of forests with nitrogen and direct injury to plants. The USDA Forest Service and University of California researchers have developed a simple and inexpensive passive sampler for monitoring air concentrations of HNO3. Nitric acid is selectively absorbed on 47-mm Nylasorb nylon filters with no interference from particulate NO3-. Concentrations determined with the passive samplers closely corresponded with those measured with the co-located honeycomb annular denuder systems. The PVC protective caps of standardized dimensions protect nylon filters from rain and wind and allow for reliable measurements of ambient HNO3 concentrations. The described samplers have been successfully used in Sequoia National Park, the San Bernardino Mountains, and on Mammoth Mountain in California.
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Affiliation(s)
- A Bytnerowicz
- USDA Forest Service, Pacific Southwest Research Station, 4955 Canyon Crest Drive, Riverside, California 92507, USA.
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Jones DP. Interviewing children about individual incidents of sexual abuse. Child Abuse Negl 2001; 25:1641-1642. [PMID: 11814160 DOI: 10.1016/s0145-2134(01)00297-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Affiliation(s)
- D P Jones
- Park Hospital for Children, Headington, Oxford, UK
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Ziegler TR, Panoskaltsus-Mortari A, Gu LH, Jonas CR, Farrell CL, Lacey DL, Jones DP, Blazar BR. Regulation of glutathione redox status in lung and liver by conditioning regimens and keratinocyte growth factor in murine allogeneic bone marrow transplantation. Transplantation 2001; 72:1354-62. [PMID: 11685103 DOI: 10.1097/00007890-200110270-00004] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Reactive oxygen species (ROS) and glutathione (GSH) depletion contribute to organ injury after bone marrow transplantation (BMT). Keratinocyte growth factor (KGF) ameliorates graft-versus-host disease (GVHD)-associated organ injury in murine BMT models. METHODS B10.BR mice received total body irradiation (TBI; day -1) +/- cyclophosphamide (Cy; 120 mg/kg/day i.p., days -3 and -2), then were transplanted on day 0 with C57BL/6 bone marrow + spleen cells as a source of GVHD-causing T cells. KGF (5 mg/kg/day subcutaneously [s.c.]) or saline was given on days -6, -5, and -4. Lung and liver GSH and oxidized GSH disulfide (GSSG) levels were measured on days 0 and 5 and glutathione redox potential (Eh) calculated. Organ malondialdehyde (MDA) was determined on day 5 as an index of ROS-mediated lipid peroxidation. RESULTS In lung, TBI+BMT oxidized GSH Eh and increased MDA. Cy further oxidized lung GSH Eh. In liver, neither BMT regimen altered GSH redox status or MDA. KGF prevented the decrease in lung GSH after TBI+Cy and decreased lung MDA after both TBI and TBI+Cy. KGF increased liver GSH levels and GSH Eh after TBI and GSH Eh after TBI+Cy. CONCLUSIONS In murine allogeneic BMT, TBI oxidizes the lung GSH redox pool and Cy exacerbates this response by 5 days post-BMT. In contrast, liver GSH redox status is maintained under these experimental conditions. KGF treatment attenuates the Cy-induced decrease in lung GSH, decreases post-BMT lung lipid peroxidation, and improves liver GSH redox indices. KGF may have a therapeutic role to prevent or attenuate GSH depletion and ROS-mediated organ injury in BMT.
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Affiliation(s)
- T R Ziegler
- Department of Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA.
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21
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22
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Abstract
A range of compounds in or derived from the diet modulates apoptosis in cell cultures in vitro. These observations have important implications concerning the mechanisms whereby dietary components affect health. Proapoptotic compounds could protect against cancer by enhancing elimination of initiated, precancerous cells, and antiapoptotic compounds could promote tumor formation by inhibiting apoptosis in genetically damaged cells. Proapoptotic compounds could also contribute to age-related degenerative diseases by activating cell death in postmitotic cells or shifting the normal balance of mitosis and apoptosis in tissues with regenerative capacity. Many age-related diseases, for example macular degeneration and Parkinson's disease, appear to have oxidative stress as an underlying component that interacts with genetic, dietary, and environmental factors to determine relative risk in an individual. Oxidative stress activates apoptosis, and antioxidants protect against apoptosis in vitro; thus, a central role of dietary antioxidants may be to protect against apoptosis. However, little in vivo data are available to directly link diet with altered apoptosis as an underlying determinant of disease. Moreover, the possible antagonistic effects of different dietary components and the uncertainty about whether proapoptotic compounds that may protect against cancer could contribute to degenerative diseases and vice versa indicate that there is a great need for better in vivo assessment of apoptosis and that caution should be exercised when extrapolating in vitro data on apoptosis to in vivo dietary recommendations.
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Affiliation(s)
- W H Watson
- Departments of Biochemistry and Ophthalmology, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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Abstract
The nephrotoxicity of trichloroethylene and dichloroacetylene has previously been linked to mitochondrial dysfunction induced by the metabolite S-(1,2-dichlorovinyl)-l-cysteine (DCVC). In this study, we examined whether key biochemical steps associated with mitochondria occur in DCVC-induced apoptosis in cultured porcine proximal tubular LLC-PK1 cells. DCVC caused a decrease in mitochondrial membrane potential (mt Delta Psi) beginning at 4 h and a release of cytochrome c into the cytoplasm at 6 h. Caspase-3-like activity was detected at 6 h and extensive DNA fragmentation was observed at 8 h. Decreases in cellular ATP were not evident until 8 h and later, even though electron microscopy showed that the mitochondria were extensively swollen. Aminooxyacetic acid (AOAA), an inhibitor of cysteine-conjugate beta-lyase, protected against mitochondrial changes and apoptosis. Overexpression of the antiapoptotic Bcl-2 protein desensitized LLC-PK1 cells to DCVC-induced apoptosis. These results support the interpretation that mitochondrial release of cyt c and cyt c-dependent activation of caspase-3 could have a central role in nephrotoxicity due to haloalkene-derived cysteine S-conjugates.
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Affiliation(s)
- Y Chen
- Program of Biochemistry, Cell Biology and Developmental Biology, Emory University, Atlanta, Georgia 30322, USA
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25
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Abstract
Pulse oximeter probes placed peripherally may fail to give accurate values of arterial blood oxygen saturation (SpO2) when peripheral perfusion is poor. Since central blood flow may be preferentially preserved, the oesophagus was suggested as an alternative monitoring site. A reflectance oesophageal photoplethysmographic (PPG) probe and a multiplexed data acquisition system, operating simultaneously at two wavelengths and incorporating an external three-lead electrocardiogram (ECG) reference channel, has been developed. It has been used to investigate the suitability of the oesophagus as a possible monitoring site for SpO2 in cases of compromised peripheral perfusion. Oesophageal PPG signals and standard ECG traces were obtained from 16 anaesthetized patients and displayed on a laptop computer. Measurable PPG signals with high signal-to-noise ratios at both infrared and red wavelengths were obtained from all five oesophageal depths investigated. The maximum PPG amplitude occurred at 25 cm from the upper incisors in the mid-oesophagus. The measured pulse transit times (PTTs) to the oesophagus were consistent with previous measurements at peripheral sites and had a minimum value of 67 +/- 30 ms at a depth of 30 cm. There was broad agreement between the calculated values of oesophageal SpO2 and those from a commercial finger pulse oximeter.
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Affiliation(s)
- P A Kyriacou
- Department of Medical Electronics and Physics, St. Bartholomew's and The Royal London School of Medicine and Dentistry, Queen Mary and Westfield College, UK
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Abstract
We report the first case of peritonitis caused by Curvularia species in a child undergoing peritoneal dialysis. He presented with gray-black proteinaceous material obstructing the lumen of his Tenckhoff catheter. Although the peritoneal fluid was cloudy, the patient suffered neither significant abdominal tenderness nor systemic symptoms. Catheter removal and treatment with amphotericin B allowed complete recovery and return to peritoneal dialysis within 7 days. Outdoor play in a wooded environment may have allowed contact of this saprophytic fungus with the child's indwelling catheter transfer set.
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Affiliation(s)
- H L Canon
- Le Bonheur Children's Medical Center, University of Tennessee, Memphis, Department of Pediatrics, Crippled Children's Research Center, Memphis, Tennessee, USA
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27
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Abstract
The control of luminal thiol-disulfide redox state may be important for several intestinal functions, including absorption of iron or selenium and maintenance of mucus fluidity. Disulfides are present in the diet, and although luminal thiols are supplied in bile, little is known about the ability of the small intestine to reduce disulfides to maintain the luminal thiol-disulfide redox state. The objective of the current study was to determine whether the isolated, vascularly perfused jejunum, free from biliary thiols, could reduce intraluminal glutathione disulfide (GSSG) to glutathione (GSH). GSSG was introduced in a deoxygenated solution to inhibit the reoxidation of any GSH formed, and preparations were pretreated with acivicin to inhibit the degradation of GSH by gamma-glutamyltransferase. GSSG (250 micromol/L) was reduced to GSH, with the luminal redox potential (E(h)) for GSSG/2GSH changing from >0 to -111, -132 and -143 mV at 10, 20 and 30 min, respectively. The E(h) for luminal cystine/2cysteine was approximately 20 mV more reducing than that for GSSG/2GSH at each time point, suggesting that cysteine could function in the reduction of GSSG in the lumen. Measurements in specific regions showed that GSSG reduction was more rapid in the duodenum and proximal jejunum than in the distal jejunum. Preparations without acivicin treatment showed that E(h) values were unaffected by inhibition of gamma-glutamyltransferase despite differences in GSH and cysteine pool sizes. Rat intestine has a mechanism to adjust the luminal thiol-disulfide redox. In principle, dysfunction of this mechanism could contribute to malabsorption or other nutritional disorders.
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Affiliation(s)
- L J Dahm
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
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Jones DP, Tucker-Allen S. Mentor/mentee relationship with the focus on meeting promotion/tenure guidelines. ABNF J 2000; 11:113-6. [PMID: 11760250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
Mentoring, an important concept in career development, is applied primarily in the literature to undergraduate students whereby faculty mentor students. This article discusses the development of a mentoring relationship in a complex university environment, factors that inhibit the development of a mentoring relationship, how to overcome these inhibitors and how attitudes can influence the mentoring relationship. Lastly, the development of a personal mentoring relationship is shared.
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Affiliation(s)
- D P Jones
- Department of Nursing, College of Health Sciences, Chicago State University, Chicago, Illinois, USA.
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Cai J, Wallace DC, Zhivotovsky B, Jones DP. Separation of cytochrome c-dependent caspase activation from thiol-disulfide redox change in cells lacking mitochondrial DNA. Free Radic Biol Med 2000; 29:334-42. [PMID: 11035262 DOI: 10.1016/s0891-5849(00)00312-9] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Release of mitochondrial cytochrome c (cyt c) is an early and common event during apoptosis. Previous studies showed that the loss of cyt c triggered superoxide production by mitochondria and contributed to the oxidation of cellular thiol-disulfide redox state. In this study, we tested whether loss of the functional electron transport chain due to depleting mitochondrial DNA (mtDNA) would affect this redox-signaling mechanism during apoptosis. Results showed that cyt c release and caspase activation in response to staurosporine treatment were preserved in cells lacking mitochondrial DNA (rho0 cells). However, unlike the case with rho+ cells, in which a dramatic oxidation of intracellular glutathione (GSH) occurred after mitochondrial cyt c release, the thiol-disulfide redox state in apoptotic rho0 cells remained largely unchanged. Thus, mitochondrial signaling of caspase activation can be separated from the bioenergetic function, and mitochondrial respiratory chain is the principal source of ROS generation in staurosporine-induced apoptosis.
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Affiliation(s)
- J Cai
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
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Jonas CR, Puckett AB, Jones DP, Griffith DP, Szeszycki EE, Bergman GF, Furr CE, Tyre C, Carlson JL, Galloway JR, Blumberg JB, Ziegler TR. Plasma antioxidant status after high-dose chemotherapy: a randomized trial of parenteral nutrition in bone marrow transplantation patients. Am J Clin Nutr 2000; 72:181-9. [PMID: 10871578 DOI: 10.1093/ajcn/72.1.181] [Citation(s) in RCA: 121] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Chemotherapy and radiation therapy result in increased free radical formation and depletion of tissue antioxidants. It is not known whether parenteral nutrition (PN) administered during bone marrow transplantation (BMT) supports systemic antioxidant status. OBJECTIVE The aims of the study were to determine 1) whether high-dose chemotherapy decreases concentrations of major circulating antioxidants in patients undergoing BMT and 2) whether administration of standard PN maintains systemic antioxidant concentrations compared with PN containing micronutrients and minimal lipids alone. DESIGN Twenty-four BMT patients were randomly assigned to receive either standard PN containing conventional amounts of dextrose, amino acids, micronutrients, and lipid (120 kJ/d) or a solution containing only micronutrients (identical to those in standard PN) and a small amount of lipid (12 kJ/d). Plasma antioxidant status was measured before conditioning therapy and serially at days 1, 3, 7, 10, and 14 after BMT. RESULTS Plasma glutathione (GSH) and alpha- and gamma-tocopherol concentrations decreased and the GSH redox state became more oxidized after conditioning chemotherapy. Plasma cysteine concentrations were unchanged, whereas cystine concentrations increased. Plasma vitamin C and zinc concentrations and GSH peroxidase activity increased over time. Plasma alpha-tocopherol concentrations were lower in patients given standard PN. There were no differences in other plasma antioxidants between groups. CONCLUSIONS A significant decline in GSH-glutathione disulfide, cysteine-cystine, and vitamin E status occurs after chemotherapy and BMT. Standard PN does not improve antioxidant status compared with administration of micronutrients alone. Further evaluation of PN formulations to support patients undergoing high-dose chemotherapy and BMT are needed.
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Affiliation(s)
- C R Jonas
- Departments of Medicine, Biochemistry, and Surgery and the Nutrition and Health Sciences Program, Emory University Schalphaool of Medicine, Atlanta, GA 30322, USA
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Abstract
STUDY DESIGN An experimental model to assess radiation exposure during lumbar pedicle screw insertion. OBJECTIVES To measure skin (patient) and scatter (surgeon) doses of radiation during lumbar spine fluoroscopy to assess safety of the procedure for both the surgeon and patient and determine best practice. SUMMARY OF BACKGROUND DATA Fluoroscopy assists with accuracy of pedicle screw placement, yet the optimal technique of C-arm use and risk to both patient and operating room staff from radiation exposure are unknown. METHODS Entry- and scatter-dose recordings were made using a digital dosimeter while screening an anthropomorphic phantom prone on a radiolucent operating table. The source was positioned both superiorly and inferiorly with the height varied in the latter orientation to create a working space under the C-arm. The senior author's fluoroscopy records were reviewed in 140 consecutive cases. RESULTS In a series of 140 patients who underwent pedicle screw fixation, the fluoroscopy time was 1.4 minutes per case or 0.33 minutes per screw. In the source-superior position, the effective dose received by the patient was approximately 2.3 mSv per case. In the source-inferior position with a working space of 300 mm, the effective dose was 6.8 mSv. Scatter dose to the surgeon was higher in the source-superior position but was still less than 10% of recommended limits for the hand, thyroid, and eyes. CONCLUSIONS The source-superior position is the preferred position for pedicle screw screening if a working space is required. Patient exposure is minimized, and surgeon dose is well within current recommendations.
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Rzucidlo SJ, Bounous DI, Jones DP, Brackett BG. Acute acetaminophen toxicity in transgenic mice with elevated hepatic glutathione. Vet Hum Toxicol 2000; 42:146-50. [PMID: 10839317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Previous studies demonstrated that elevation of hepatic glutathione (GSH) concentrations protect against acetaminophen (APAP) hepatotoxicity in mice. Employing transgenic mice overexpressing glutathione synthetase, this study was conducted to determine if sustained elevation of hepatic GSH concentrations could ameliorate or prevent APAP toxicity. International Cancer Research transgenic mouse males and matched (ie same strain, sex, and age) control nontransgenic mice were pretreated ip with GSH synthetase substrate gamma-glutamylcysteinyl ethyl ester (gamma-GCE) or with saline. After a 16-h fast, mice received a single dose of 500 mg APAP/kg bw in saline ip and were sacrificed 4 h later. Other mice similarly pretreated were killed without APAP challenge. The elevated GSH concentrations in transgenic mice livers did not lessen APAP hepatotoxicity. Instead higher degrees of hepatotoxicity and nephrotoxicity were observed in transgenic mice than in controls as indicated by higher serum alanine aminotransferase activity and more severe histopathological lesions in transgenic mice livers and kidneys. Pretreatment with gamma-GCE did not affect either initial or post-APAP treatment tissue GSH concentrations or observed degrees of toxicity. Detection of a higher level of serum APAP in transgenic mice and the histopathological lesions found in transgenic mice kidneys together with no observable nephrotoxicity in control mice indicated early kidney damage in transgenic mice. Our findings suggest that high levels of GSH-APAP conjugates resulting from increased GSH concentrations in the livers of transgenic mice caused rapid kidney damage. Compromised excretory ability may have caused retention of APAP, which, in effect, elicited higher hepatotoxicity than that observed in nontransgenic mice.
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Affiliation(s)
- S J Rzucidlo
- Department of Physiology and Pharmacology, College of Veterinary Medicine, University of Georgia, Athens 30602, USA
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Pickett JA, Thorniley MS, Balogun E, Jones DP. A dual wavelength spectrophotometer for use in plastic surgery. Comparison with a Hamamatsu NIRO-500 instrument. Adv Exp Med Biol 2000; 471:723-30. [PMID: 10659207 DOI: 10.1007/978-1-4615-4717-4_83] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- J A Pickett
- St. Bartholomew's Hospital NHS Trust, Whitechapel, London, United Kingdom
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Kadiiska MB, Gladen BC, Baird DD, Dikalova AE, Sohal RS, Hatch GE, Jones DP, Mason RP, Barrett JC. Biomarkers of oxidative stress study: are plasma antioxidants markers of CCl(4) poisoning? Free Radic Biol Med 2000; 28:838-45. [PMID: 10802213 DOI: 10.1016/s0891-5849(00)00198-2] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Antioxidants in the blood plasma of rats were measured as part of a comprehensive, multilaboratory validation study searching for noninvasive biomarkers of oxidative stress. For this initial study an animal model of CCl(4) poisoning was studied. The time (2, 7, and 16 h) and dose (120 and 1200 mg/kg, intraperitoneally)-dependent effects of CCl(4) on plasma levels of alpha-tocopherol, coenzyme Q (CoQ), ascorbic acid, glutathione (GSH and GSSG), uric acid, and total antioxidant capacity were investigated to determine whether the oxidative effects of CCl(4) would result in losses of antioxidants from plasma. Concentrations of alpha-tocopherol and CoQ were decreased in CCl(4)-treated rats. Because of concomitant decreases in cholesterol and triglycerides, it was impossible to dissociate oxidation of alpha-tocopherol and the loss of CoQ from generalized lipid changes, due to liver damage. Ascorbic acid levels were higher with treatment at the earliest time point; the ratio of GSH to GSSG generally declined, and uric acid remained unchanged. Total antioxidant capacity showed no significant change except for 16 h after the high dose, when it was increased. These results suggest that plasma changes caused by liver malfunction and rupture of liver cells together with a decrease in plasma lipids do not permit an unambiguous interpretation of the results and impede detection of any potential changes in the antioxidant status of the plasma.
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Affiliation(s)
- M B Kadiiska
- National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA.
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Jones DP. Re-focusing child protective services. Child Abuse Negl 2000; 24:373-374. [PMID: 10739080 DOI: 10.1016/s0145-2134(99)00147-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Jonas CR, Farrell CL, Scully S, Eli A, Estívariz CF, Gu LH, Jones DP, Ziegler TR. Enteral nutrition and keratinocyte growth factor regulate expression of glutathione-related enzyme messenger RNAs in rat intestine. JPEN J Parenter Enteral Nutr 2000; 24:67-75. [PMID: 10772185 DOI: 10.1177/014860710002400267] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
BACKGROUND Malnutrition is associated with increased reactive oxygen species (ROS) formation and depletion of the critical antioxidant glutathione (GSH) in the intestine. The malnutrition-induced decrease in gut GSH levels is prevented by recombinant keratinocyte growth factor (KGF) administration. We investigated whether enzymes that are induced by oxidants and modulate tissue GSH supply are regulated by enteral nutrients or KGF at the messenger RNA (mRNA) level. METHODS Adult rats were fasted for 3 days alone or fasted for 3 days then refed ad libitum. In a second model, rats were fasted for 3 days and then refed ad libitum or 25% of ad libitum intake with daily intraperitoneal saline or recombinant KGF (5 mg/kg/d) for 3 subsequent days. mRNA levels for gamma-glutamylcysteine synthetase (gamma-GCS), gamma-glutamyl transpeptidase (gamma-GT), glutathione-S-transferase Ya-subunit, gastrointestinal glutathione peroxidase (GI-GPx), and non-selenium-dependent glutathione peroxidase (ns-GPx) were determined in ileum and colon by ribonuclease protection assay. RESULTS Fasting increased ileal gamma-GCS, ns-GPx, and glutathione-S-transferase mRNAs (by 36%, 165%, and 130% of controls) and decreased GI-GPx mRNA (to 55% of controls). In the colon, mRNAs for GSH-related enzymes were unchanged by fasting or refeeding. Prolonged enteral nutrient restriction (25% refeeding after a 3-day fast) increased gamma-GCS and glutathione-S-transferase mRNAs (by >270% of controls), decreased GI-GPx mRNA (to <50% of controls) in ileum and colon and increased ns-GPx mRNA (by 180%) in colon. KGF treatment increased ns-GPx mRNA in the ileum and colon and glutathione-S-transferase mRNA in the colon (by >200% of controls). CONCLUSIONS Enteral nutrient intake regulates GSH-related enzyme mRNA levels in the intestine, which may contribute to the decrease in mucosal GSH during malnutrition. Increased ns-GPx and glutathione-S-transferase mRNA levels during malnutrition and with KGF administration may increase detoxifying functions in the gut under these conditions.
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Affiliation(s)
- C R Jonas
- Department of Medicine, Emory University, Atlanta, Georgia 30322, USA
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Jiang S, Wu MW, Sternberg P, Jones DP. Fas mediates apoptosis and oxidant-induced cell death in cultured hRPE cells. Invest Ophthalmol Vis Sci 2000; 41:645-55. [PMID: 10711676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023] Open
Abstract
PURPOSE To investigate whether Fas ligand (FasL) and the Fas receptor system mediates apoptosis in cultured human retinal pigment epithelial (hRPE) cells and contributes to oxidant-induced death of hRPE cells. METHODS Expression of FasL and Fas in cultured hRPE cells was examined by Western blot analysis and flow cytometry. The susceptibility of hRPE cells to Fas-mediated apoptosis was determined by incubating cells with recombinant soluble Fas ligand (sFasL). Characteristics of apoptosis assessed included chromatin condensation, DNA cleavage, and phosphatidylserine exposure. To investigate the possible involvement of Fas-mediated apoptosis in oxidative killing of hRPE cells, the effects of the oxidant tert-butylhydroperoxide (tBH) on the expression of FasL and Fas were studied. The specificity of effects of oxidant was examined using the antioxidants glutathione and N-acetyl-L-cysteine (NAC). The requirement for the Fas pathway in tBH-induced apoptosis was investigated using an antagonistic anti-Fas antibody ZB4 that blocks the interaction between FasL and Fas. RESULTS Cultured hRPE cells constitutively expressed FasL and Fas. Ligation of Fas receptor with recombinant sFasL triggered apoptosis in hRPE cells. tBH treatment of hRPE cells resulted in increased expression of FasL and Fas. Glutathione and NAC completely abrogated tBH-induced increase in FasL and Fas expression and apoptosis. Blocking FasL and Fas interaction by ZB4 inhibited tBH-induced apoptosis, but only partially. CONCLUSIONS A functional Fas-mediated apoptotic pathway is present in cultured hRPE cells and can be activated with sFasL or by upregulation of FasL and Fas expression with an oxidant. The incomplete inhibition by blocking antibody indicates that the Fas pathway is involved in oxidant-induced apoptosis, but other triggering mechanisms are also important.
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Affiliation(s)
- S Jiang
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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Jones DP. Recalling childhood experiences. Child Abuse Negl 2000; 24:389-390. [PMID: 10739082 DOI: 10.1016/s0145-2134(99)00155-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Abstract
Glutathione S-transferases in the small intestine function in detoxification of electrophilic compounds ingested in foods, dietary supplements, and orally administered drug preparations. Although the required substrate glutathione (GSH) is synthesized in the intestinal enterocytes, the rate of synthesis is slow compared to both the maximal GST activity and the rate of uptake of luminal GSH. GSH is supplied to the intestinal lumen in the bile, and normal luminal concentrations in the rat are about 250 microM. The present study was designed to test the hypothesis that exogenous GSH is used for intestinal conjugation by glutathione S-transferase. The results show that 250 microM of extracellular GSH stimulated conjugation of 1-chloro-2,4-dinitrobenzene by approximately 300% in rat intestinal enterocyte preparations. However, an unexpected finding was that most of this stimulated activity did not depend upon uptake of GSH by the enterocytes but was due to glutathione S-transferase associated with mucus. Immunohistochemistry of glutathione S-transferase in the intact small intestine confirmed that a portion of the GST is present in the mucus layer. The presence of this detoxication enzyme in the extracellular mucus layer provides a novel mechanism for preventing direct contact of potentially toxic dietary electrophiles with the intestinal enterocytes.
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Affiliation(s)
- P S Samiec
- Department of Biochemistry, Emory University, Atlanta, Georgia 30322, USA
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Abstract
This review provides a model for the role of oxidative stress in the etiology of age-related macular degeneration (AMD). Epidemiological studies of diet, environmental and behavioral risk factors suggest that oxidative stress is a contributing factor of AMD. Pathological studies indicate that damage to the retinal pigment epithelium (RPE) is an early event in AMD. In vitro studies show that oxidant treated RPE cells undergo apoptosis, a possible mechanism by which RPE cells are lost during early phase of AMD. The main target of oxidative injury seems to be mitochondria, an organelle known to accumulate genomic damages in other postmitotic tissues during aging. The thiol antioxidant GSH and its amino acid precursors protect RPE cells from oxidant-induced apoptosis. Similar protection occurs with dietary enzyme inducers which increase GSH synthesis. These results indicate that therapeutic or nutritional intervention to enhance the GSH antioxidant capacity of RPE may provide an effective way to prevent or treat AMD.
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Affiliation(s)
- J Cai
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
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Abstract
Thiol and disulfide forms of glutathione (GSH) and cysteine (Cys) were measured in plasma from 24 healthy individuals aged 25-35 and redox potential values (E(h)) for thiol/disulfide couples were calculated using the Nernst equation. Although the concentration of GSH (2.8 +/- 0.9 microM) was much greater than that of GSSG (0.14 +/- 0.04 microM), the redox potential of the GSSG/2GSH pool (-137 +/- 9 mV) was considerably more oxidized than values for tissues and cultured cells (-185 to -258 mV). This indicates that a rapid oxidation of GSH occurs upon release into plasma. The difference in values between individuals was remarkably small, suggesting that the rates of reduction and oxidation in the plasma are closely balanced to maintain this redox potential. The redox potential for the Cys and cystine (CySS) pool (-80 +/- 9 mV) was 57 mV more oxidized, showing that the GSSG/2GSH and the CySS/2Cys pools are not in redox equilibrium in the plasma. Potentials for thiol/disulfide couples involving CysGly were intermediate between the values for these couples. Regression analyses showed that the redox potentials for the different thiol/disulfide couples within individuals were correlated, with the E(h) for CySS-mono-Gly/(Cys. CysGly) providing the best correlation with other low molecular weight pools as well as protein disulfides of GSH, CysGly and Cys. These results suggest that E(h) values for GSSG/2GSH and CySS-mono-Gly/(Cys. CysGly) may provide useful means to quantitatively express the oxidant/antioxidant balance in clinical and epidemiologic studies.
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Affiliation(s)
- D P Jones
- Department of Biochemistry, Atlanta, GA, USA.
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Abstract
AIM To assess the incidence and nature of concerns about sexual abuse, with particular reference to erroneous concerns of sexual abuse made by children. METHODS A review of case notes of all child sexual abuse reports to the Denver Department of Social Services over 12 months. Cases were put into four groups: substantiated, not sexual abuse, inconclusive and erroneous accounts by children. RESULTS 551 cases were reviewed. Forty-three percent were substantiated, 21% were inconclusive and 34% were not considered to be abuse cases. There were 14 (2.5%) erroneous concerns emanating from children. They comprised three cases of allegations made in collusion with a parent, three cases where an innocent event was misinterpreted as sexual abuse and eight cases (1.5%) of false allegations of sexual abuse. CONCLUSION Erroneous concern of sexual abuse from children are uncommon. The four categories of concern in this study, in contrast to the simple classification of substantiated and unsubstantiated, provide a means of encouraging open minded assessments of the typical concerns which a child protection agency receives.
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Affiliation(s)
- R K Oates
- Department of Pediatrics & Child Health, The University of Sydney, The New Children's Hospital, Westmead, NSW, Australia
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45
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Abstract
The reduced glutathione (GSH)/oxidized glutathione (GSSG) redox state is thought to function in signaling of detoxification gene expression, but also appears to be tightly regulated in cells under normal conditions. Thus it is not clear that the magnitude of change in response to physiologic stimuli is sufficient for a role in redox signaling under nontoxicologic conditions. The purpose of this study was to determine the change in 2GSH/GSSG redox during signaling of differentiation and increased detoxification enzyme activity in HT29 cells. We measured GSH, GSSG, cell volume, and cell pH, and we used the Nernst equation to determine the changes in redox potential Eh of the 2GSH/GSSG pool in response to the differentiating agent, sodium butyrate, and the detoxification enzyme inducer, benzyl isothiocyanate. Sodium butyrate caused a 60-mV oxidation (from -260 to -200 mV), an oxidation sufficient for a 100-fold change in protein dithiols:disulfide ratio. Benzyl isothiocyanate caused a 16-mV oxidation in control cells but a 40-mV oxidation (to -160 mV) in differentiated cells. Changes in GSH and mRNA for glutamate:cysteine ligase did not correlate with Eh; however, correlations were seen between Eh and glutathione S-transferase (GST) and nicotinamide adenine dinucleotide phosphate (NADPH):quinone reductase activities (N:QR). These results show that 2GSH/GSSG redox changes in response to physiologic stimuli such as differentiation and enzyme inducers are of a sufficient magnitude to control the activity of redox-sensitive proteins. This suggests that physiologic modulation of the 2GSH/GSSG redox poise could provide a fundamental parameter for the control of cell phenotype.
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Affiliation(s)
- W G Kirlin
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
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46
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Abstract
OBJECTIVE To determine the outcome for children after psychiatric intervention in cases of factitious illness by proxy. METHODS All 17 children from 16 families, selected for admission to the Park Hospital Oxford family unit 1992-96 were followed up after a mean of 27 months. Information was obtained on the children and their carers from general practitioners, social workers or both; 13 of the children and carers were interviewed. RESULTS All patients were at the severe end of the abuse spectrum; 12 involving direct induction of illness, 1 tampering with samples to mimic illness, and 4 fabrication of symptoms. The biological mother was the abuser in all cases. Four children and their parents had been initially admitted for assessment, and 13 for treatment to decide whether family reunification was viable. The 4 assessments clarified diagnosis, enabling improved care plans to be made. Of the 13 treatment cases, 10 were reunited with parents after a mean of 71/2 weeks' admission, whereas 3 were discharged to out of home care. There was a further episode of induced illness in 1 of the reunited children. Although some mothers had continuing mental health difficulties, only 1 of the other reunited cases had appreciable parent-child relationship difficulties (not requiring referral to psychiatric services). The children did well in their development, growth, and adjustment. CONCLUSION Family reunification is feasible for certain cases, but long term follow up is necessary to ensure the child's safety and to identify deterioration in parent's mental health. The outcome for reunited children compared well with reported untreated cases.
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Affiliation(s)
- B Berg
- Park Hospital for Children, Old Road, Headington, Oxford OX3 7LQ, UK
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Jones DP. Intervention. Child Abuse Negl 1999; 23:1341-1344. [PMID: 10626615 DOI: 10.1016/s0145-2134(99)00087-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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48
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Ziegler TR, Estívariz CF, Jonas CR, Gu LH, Jones DP, Leader LM. Interactions between nutrients and peptide growth factors in intestinal growth, repair, and function. JPEN J Parenter Enteral Nutr 1999; 23:S174-83. [PMID: 10571452 DOI: 10.1177/014860719902300602] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Several lines of evidence demonstrate that general nutritional status, specific nutrients (eg, zinc, glutamine), and certain trophic growth factors (eg, growth hormone, insulin-like growth factor I, keratinocyte growth factor, and glucagon-like peptide-2) have important interactions relevant for intestinal growth and function. Adequate nutritional status is critical for endogenous growth factor synthesis in the gut and other tissues and is an important mediator of organ responsiveness to exogenous growth factor administration. Both endogenously synthesized and exogenously administered growth factors upregulate nutrient uptake and utilization by gut mucosa, skeletal muscle, and other organs. Emerging data from both animal and human studies indicate that combinations of selected growth factors and specific nutrients may improve the growth, adaptation, and repair of the intestinal mucosa. Additional studies to determine basic mechanisms of nutrient-growth factor interactions and the safety and efficacy of treatment with combinations of specific nutrients and recombinant growth factors are needed. Results of these investigations should define new methods for support of the intestinal tract during short bowel syndrome (SBS), catabolic illness, and malnutrition.
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Affiliation(s)
- T R Ziegler
- Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
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49
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Jiang S, Cai J, Wallace DC, Jones DP. Cytochrome c-mediated apoptosis in cells lacking mitochondrial DNA. Signaling pathway involving release and caspase 3 activation is conserved. J Biol Chem 1999; 274:29905-11. [PMID: 10514472 DOI: 10.1074/jbc.274.42.29905] [Citation(s) in RCA: 138] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mitochondria serve as a pivotal component of the apoptotic cell death machinery. However, cells that lack mitochondrial DNA (rho(0) cells) retain apparently normal apoptotic signaling. In the present study, we examined mitochondrial mechanisms of apoptosis in rho(0) osteosarcoma cells treated with staurosporine. Immunohistochemistry revealed that rho(0) cells maintained a normal cytochrome c distribution in mitochondria even though these cells were deficient in respiration. Upon staurosporine treatment, cytochrome c was released concomitantly with activation of caspase 3 and loss of mitochondrial membrane potential (Deltapsi(m)). After mitochondrial loss of cytochrome c, rho(0) cells underwent little change in glutathione (GSH) redox potential whereas a dramatic oxidation in GSH/glutathione disulfide (GSSG) pool occurred in parental rho(+) cells. These results show that mitochondrial signaling of apoptosis via cytochrome c release was preserved in cells lacking mtDNA. However, intracellular oxidation that normally accompanies apoptosis was lost, indicating that the mitochondrial respiratory chain provides the major source of redox signaling in apoptosis.
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Affiliation(s)
- S Jiang
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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50
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Kirlin WG, Cai J, DeLong MJ, Patten EJ, Jones DP. Dietary compounds that induce cancer preventive phase 2 enzymes activate apoptosis at comparable doses in HT29 colon carcinoma cells. J Nutr 1999; 129:1827-35. [PMID: 10498754 DOI: 10.1093/jn/129.10.1827] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Dietary agents that induce glutathione S-transferases and related detoxification systems (Phase 2 enzyme inducers) are thought to prevent cancer by enhancing elimination of chemical carcinogens. The present study shows that compounds of this group (benzyl isothiocyanate, allyl sulfide, dimethyl fumarate, butylated hydroxyanisole) activated apoptosis in human colon carcinoma (HT29) cells in culture over the same concentration ranges that elicited increases in enzyme activity (5-25, 25-100, 10-100, 15-60 micromol/L, respectively). Pretreatment of cells with sodium butyrate, an agent that induces HT29 cell differentiation, resulted in parallel increases in Phase 2 enzyme activities and induction of apoptosis in response to the inducers. Cell death characteristics included apoptotic morphological changes, appearance of cells at sub-G1 phase on flow cytometry, caspase activation, DNA fragmentation and TUNEL-positive staining. The results suggest that dietary Phase 2 inducers may protect against cancer by a mechanism distinct from and in addition to that associated with enhanced elimination of carcinogens. If this occurs in vivo, diets high in such compounds could eliminate precancerous cells by apoptosis at time points well after initial exposure to chemical mutagens and carcinogens.
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Affiliation(s)
- W G Kirlin
- Department of Biochemistry, Winship Cancer Center, Emory University, Atlanta, GA 30322, USA
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