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Hanger HC, Walker G, Paterson LA, McBride S, Sainsbury R. What do patients and their carers want to know about stroke? A two-year follow-up study. Clin Rehabil 1998; 12:45-52. [PMID: 9549025 DOI: 10.1191/026921598668677675] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE To clarify what issues are important to stroke patients and their carers. To determine whether these issues change over time. DESIGN Prospective study of consecutive patients admitted to hospital with a diagnosis of an acute stroke. Each participant had interviews at six and 24 months. In addition, a subgroup of these patients (consecutive discharges over a two-month period) were also seen at two weeks post discharge. SETTING AND SUBJECTS Hospital-based cohort of stroke survivors. Interviewed in their own homes. MAIN OUTCOMES MEASURES Documentation of the questions asked. RESULTS At two weeks, six and 24 months, a median of three, two and three questions were asked by each patient respectively. Enquiries about basic aspects of stroke were common but diminished over time. Fear of recurrence was apparent at all three interview periods. Enquiries about the psychological sequelae of stroke became more prevalent at six and 24 months. At two years, 32% of respondents asked about concentration/memory difficulties with smaller numbers commenting on tiredness, depression and frustration. At two years, 18% of the sample were still uncertain of their chances of further recovery. CONCLUSIONS Patients with stroke continue to have unanswered questions even two years after their stroke. The types of questions asked changed over time.
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Kunz D, Walker G, Eberhardt W, Messmer UK, Huwiler A, Pfeilschifter J. Platelet-derived growth factor and fibroblast growth factor differentially regulate interleukin 1beta- and cAMP-induced nitric oxide synthase expression in rat renal mesangial cells. J Clin Invest 1997; 100:2800-9. [PMID: 9389745 PMCID: PMC508485 DOI: 10.1172/jci119827] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Platelet-derived growth factor (PDGF) and basic fibroblast growth factor (bFGF) regulate mesangial cell proliferation and matrix production in vitro and in vivo and crucially participate in the pathogenesis of glomerulonephritis. We investigated whether PDGF-BB and bFGF influence nitric oxide (NO) production, another important effector molecule in inflammatory glomerular injury. Inducible NO synthase (iNOS) induction in rat glomerular mesangial cells has been described in response to two principal classes of activating signals comprising inflammatory cytokines such as interleukin 1beta (IL-1beta) or elevation of cyclic AMP (cAMP). Treatment of mesangial cells with IL-1beta induces iNOS activity measured as nitrite levels in cell culture supernatants. Coincubation of mesangial cells with PDGF-BB inhibits production of nitrite by approximately 95%. This effect can be reversed by the simultaneous incubation of PDGF-BB in the presence of calphostin C, a potent and selective inhibitor of protein kinase C. In contrast, incubation of cells in the presence of bFGF potentiates IL-1beta-induced production of NO and is functionally associated with an increased rate of apoptosis of mesangial cells. Western blot analyses reveal that PDGF-BB causes a decrease in the formation of iNOS protein which is preceded by decreases in iNOS mRNA steady state levels. bFGF drastically increases iNOS protein levels as well as the corresponding iNOS mRNA steady state levels. Nuclear run-on experiments reveal that PDGF-BB decreases the IL-1beta-induced transcription rate of the iNOS gene, whereas bFGF potentiates the transcriptional activity of the iNOS gene. Northern blot analyses demonstrate that bFGF strongly potentiates the formation of IL-1beta-induced IL-1 type I receptor mRNA levels, whereas PDGF-BB has no effect. Treatment of mesangial cells with the membrane-permeable cAMP analogue N6, O-2'-dibutyryladenosine 3',5'-phosphate (Bt2cAMP) markedly increases the production of nitrite. Whereas PDGF-BB does not affect cAMP-induced nitrite levels, bFGF strongly potentiates them. PDGF-BB alters neither cAMP-induced iNOS protein levels nor the corresponding iNOS mRNA steady state levels. By contrast, bFGF superinduces cAMP-stimulated iNOS protein and iNOS mRNA levels. These changes by bFGF are due to an increase in cAMP-induced transcriptional activity of the iNOS gene which is not affected by PDGF-BB. In summary, the results show that PDGF and bFGF differentially regulate iNOS expression in mesangial cells in a stimulus-specific way. The timely sequence of expression of PDGF and bFGF and of cytokines like IL-1 will crucially determine the amounts of NO produced and the functional consequences thereof in the course of progressive glomerular diseases.
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Kunz D, Walker G, Pfeilschifter J. Transforming growth factor-beta 2 inhibits interleukin 1 beta-induced expression of inducible nitric oxide synthase in rat renal mesangial cells. Inflamm Res 1997; 46:327-31. [PMID: 9339386 DOI: 10.1007/s000110050196] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
OBJECTIVE AND DESIGN We have investigated whether transforming growth factor beta 2 (TGF-beta 2) influences the expression of inducible nitric oxide synthase (iNOS). MATERIAL Rat renal mesangial cells exposed to the inflammatory cytokine interleukin 1 beta (IL-1 beta). RESULTS Addition of TGF-beta 2 dose-dependently suppresses IL-1 beta-induced nitrite formation. Western and Northern blot analyses of mesangial cell extracts reveal that the inhibition of IL-1 beta-induced nitrite formation by TGF-beta 2 is due to decreased iNOS protein and iNOS mRNA steady state levels. Reduction of iNOS mRNA levels is due to decreased transcriptional activity of the iNOS gene under the action of TGF-beta 2 as shown by nuclear run on experiments. CONCLUSIONS TGF-beta 2 is a potent inhibitor of iNOS expression acting by reducing the transcriptional activity of the iNOS gene.
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Ryan R, Walker G, Freeman K, Cisneros GJ. The effects of ion implantation on rate of tooth movement: an in vitro model. Am J Orthod Dentofacial Orthop 1997; 112:64-8. [PMID: 9228843 DOI: 10.1016/s0889-5406(97)70275-0] [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: 02/04/2023]
Abstract
Recently, the ion-implantation process has been applied to orthodontic wires. By altering the surface composition of a wire, the ion-implantation process supposedly decreases the frictional forces produced during tooth movement. The purpose of this study was to compare the amount of tooth movement produced by different orthodontic wire compositions, under identical conditions, by using an in vitro model. The wires tested were stainless steel, nickel-titanium (control and ion implanted), and beta-titanium (control and ion implanted). The amount of tooth movement was measured and compared. Results demonstrate that, stainless steel produced the least frictional force during in vitro tooth movement, followed by ion-implanted nickel-titanium, ion-implanted beta-titanium, untreated nickel-titanium, and finally, untreated beta-titanium. A Wilcoxon rank sum test showed statistically significant differences in the amount of movement seen with the ion-implanted wires when compared with their untreated counterparts.
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Walker G, Pfeilschifter J, Kunz D. Mechanisms of suppression of inducible nitric-oxide synthase (iNOS) expression in interferon (IFN)-gamma-stimulated RAW 264.7 cells by dexamethasone. Evidence for glucocorticoid-induced degradation of iNOS protein by calpain as a key step in post-transcriptional regulation. J Biol Chem 1997; 272:16679-87. [PMID: 9195984 DOI: 10.1074/jbc.272.26.16679] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The murine macrophage cell line RAW 264.7 expresses inducible nitric-oxide synthase (iNOS) activity upon stimulation with interferon (IFN)-gamma and/or bacterial lipopolysaccharide. We have studied the mechanisms by which the synthetic glucocorticoid dexamethasone suppresses IFN-gamma-stimulated iNOS expression in RAW 264.7 cells. Treatment of cells with dexamethasone reduces the formation of nitrite, one of the stable end products of NO production measured in culture supernatants with an IC50 of 9 nM. The reduction of iNOS activity is caused by decreased iNOS protein levels as assessed by immunoblotting using a specific anti-iNOS antibody. Dexamethasone treatment also reduces the formation of iNOS mRNA steady state levels to about 50% in IFN-gamma-stimulated cells. This is due to decreased iNOS gene transcription and iNOS mRNA stability. More importantly, dexamethasone reduces the amount of iNOS protein by two additional mechanisms: reduction of the translation of iNOS mRNA and increased degradation of the iNOS protein. Using a specific protease inhibitor for the cysteine protease calpain I, N-acetyl-Leu-Leu-norleucinal (calpain inhibitor I), the enhanced proteolysis of the iNOS protein can efficiently be blocked, whereas other protease inhibitors such as tosyl-L-lysine chloromethyl ketone have no effect. Dexamethasone does not significantly alter calpain gene expression. Northern blot analyses reveal that calpain mRNA steady state levels are virtually not affected upon incubation of the cells with IFN-gamma and dexamethasone. Immunoprecipitation using a polyclonal anti-calpain antibody reveals that calpain protein levels are also not affected by the glucocorticoid. This is the first evidence that the iNOS protein is a molecular target for the cysteine protease calpain.
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Walker G, Kunz D, Pignat W, van den Bosch H, Pfeilschifter J. Suppression by cyclosporin A of interleukin 1 beta-induced expression of group II phospholipase A2 in rat renal mesangial cells. Br J Pharmacol 1997; 121:787-93. [PMID: 9208149 PMCID: PMC1564731 DOI: 10.1038/sj.bjp.0701170] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
1. We investigated whether cyclosporin A, a potent immunosuppressive drug, affects group II phospholipase A2. (PLA2; EC 3.1.1.4) induction in rat renal mesangial cells. 2. Previously we showed that the expression of group II PLA2 in rat renal mesangial cells is triggered by exposure of the cells to inflammatory cytokines such as interleukin 1 beta (IL-1 beta) or tumour necrosis factor alpha and agents that elevate cellular levels of cyclic AMP. Treatment of mesangial cells with IL-1 beta for 24 h induced PLA2 activity secreted into cell culture supernatants by about 16 fold. Incubation of mesangial cells with cyclosporin A inhibited IL-1 beta-induced PLA2 section in a dose-dependent fashion, with an IC50 value of 4.3 microM. Cyclosporin A did not directly inhibit enzymatic activity of PLA2. 3. Immunoprecipitation of radioactively labelled PLA2 protein from mesangial cell supernatants revealed that the inhibition of PLA2 activity is due to a suppression of PLA2 protein levels. This effect was preceded by a reduction of PLA2 mRNA steady state levels, as demonstrated by Northern blot analyses of total cellular RNA isolated from stimulated mesangial cells. 4. In order to evaluate whether cyclosporin A would affect the transcriptional activity of the PLA2 gene, we performed nuclear run on transcription experiments and provided evidence that the transcription rate of the PLA2 gene is reduced by cyclosporin A. 5. Previously we found that the nuclear transcription factor kappa B (NF kappa B) is an essential component of the IL-1 beta-dependent upregulation of PLA2 gene transcription. By electrophoretic mobility shift analysis, we demonstrated that cyclosporin A diminishes the formation of NF kappa B DNA-binding complexes, thus suggesting that this transcription factor is a target for cyclosporin A-mediated repression of PLA2 gene transcription. 6. The data presented in this study strongly suggest that the cellular mechanism involved in the IL1 beta-dependent transcriptional upregulation of the PLA2 gene in mesangial cells is a target for the action of cyclosporin A.
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Abstract
In the light of many years' experience in hemodialysis access surgery, the different methods of creating vascular access for dialysis treatment in the pediatric population are described. After presenting the various access types using autologous blood vessels and also heterologous grafts, their specific spectrum of complications is discussed in detail. Summarizing our experience it has to be emphasized that there is no specific angioaccess for children and adolescents, and that most vascular access procedures used in adults are also suitable for use in the young.
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Copley RCB, Lehmann CW, Howard JAK, Wade K, Walker G, Archer JM, Trueblood KN. The Fddddiffractometer: hardware innovations and a study of [Zn(H 2O) 6][C 6H 2(COOH) 2(COO) 2]. Acta Crystallogr A 1996. [DOI: 10.1107/s0108767396097450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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184
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Nolan M, Walker G, Nolan J, Williams S, Poland F, Curran M, Kent BC. Entry to care: positive choice or fait accompli? developing a more proactive nursing response to the needs of older people and their carers. J Adv Nurs 1996; 24:265-74. [PMID: 8858429 DOI: 10.1046/j.1365-2648.1996.01966.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
A range of issues surrounding admission to either residential or nursing home care are considered from the perspectives of older people and their family carers. Drawing on the literature and a number of studies conducted by the authors, the processes and perceptions that shape and influence admission to care are identified. On the basis of the interaction of these factors a four-stage typology of admission is suggested: the positive choice, the rationalized alternative, the discredited option, and the fait accompli. The characteristics of each admission type are discussed and the implications for professionals, particularly nurses, working with older people and their carers are addressed.
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185
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Schmidt AH, Walker G, Kyle RF, Thompson RC. Periprosthetic metastatic carcinoma. Pitfalls in the management of two cases initially diagnosed as osteolysis. J Arthroplasty 1996; 11:613-9. [PMID: 8872585 DOI: 10.1016/s0883-5403(96)80119-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Periprosthetic osteolysis is a well-described phenomenon associated with total hip arthroplasty. Two cases are presented in which apparently healthy patients developed lytic lesions adjacent to cementless hip implants. Despite atypical features, the lesions were initially attributed to wear debris-induced osteolysis, and it was discovered during revision surgery that metastatic tumor was present. For one patient, if the initial diagnosis had been correct, subsequent surgery and related complications may have been avoided. It is important to consider the entire differential of radiolucent bone lesions whenever a patient presents with periprosthetic osteolysis. If revision surgery is not warranted on the basis of loosening, then a thorough medical examination, close follow-up evaluation, and/or biopsy should be performed to rule out metastatic disease.
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Kunz D, Walker G, Wiesenberg I, Pfeilschifter J. Inhibition by tetranactin of interleukin 1 beta- and cyclic AMP-induced nitric oxide synthase expression in rat renal mesangial cells. Br J Pharmacol 1996; 118:1621-6. [PMID: 8842423 PMCID: PMC1909823 DOI: 10.1111/j.1476-5381.1996.tb15583.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
1. We have investigated whether tetranactin, a cyclic antibiotic produced by Streptomyces aureus with a molecular structure related to cyclosporin A, influences inducible nitric oxide synthase (iNOS; EC 1.14.13.39) induction in rat glomerular mesangial cells. 2. Previously we have shown that iNOS is expressed in renal mesangial cells in response to two principal classes of activating signals comprising inflammatory cytokines such as interleukin 1 (IL-1) or tumour necrosis factor alpha and agents that elevate cellular levels of cyclic AMP. Treatment of mesangial cells with IL-1 beta or the membrane-permeable cyclic AMP analogue, N6, 0-2'-dibutyryladenosine 3',5'-phosphate (Bt2 cyclic AMP) for 24 h induces iNOS activity measured as nitrite levels in cell culture supernatants by 44 fold or 33 fold, respectively. Incubation of mesangial cells with tetranactin inhibits IL-1 beta- and cyclic AMP-dependent production of nitrite in a dose-dependent fashion with IC50 values of 50 nM and 10 nM, respectively. 3. Western-blot analyses of mesangial cell extracts reveal that the inhibition of nitrite synthesis by tetranactin is due to a suppression of iNOS protein levels. This effect is preceded by a reduction of iNOS mRNA steady state levels as demonstrated by Northern blot analyses of total cellular RNA isolated from stimulated mesangial cells. 4. Thus, tetranactin is a potent inhibitor of iNOS expression in cytokine- and cyclic AMP-stimulated mesangial cells and represents a new class of iNOS inhibitors with IC50s in the low nanomolar range. This compound may be useful in the therapy of diseases associated with pathological NO overproduction due to iNOS expression.
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187
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Traynor AJ, Hall ET, Walker G, Miller WH, Melançon P, Kuchta RD. Inhibition of UDP-N-acetylglucosamine import into Golgi membranes by nucleoside monophosphates. J Med Chem 1996; 39:2894-9. [PMID: 8709123 DOI: 10.1021/jm960175c] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The specificity of the UDP-N-acetylglucosamine (UDP-GlcNAc) translocator for the binding of nucleoside monophosphates (NMPs) and nucleotide-sugars was examined in order to develop a quantitative understanding of how this enzyme recognizes its substrates and to provide a framework for development of novel drugs that target glycosylation. Competition studies reveal that tight binding requires a complete ribose ring and a 5'-phosphate. The enzyme is extremely tolerant to changes at the 3'-position, and the presence of 3'-F actually increases binding of the NMP to the enzyme. At the 2'-position, substitutions in the ribo configuration are well tolerated, although these same substitutions greatly diminish binding when present in the ara configuration. For the base, size appears to be the key feature for discrimination. The enzyme tolerates changing the C-4 oxygen of uridine to an amino group as well as substituting groups containing one or two carbons at C-5. However, substitution of groups containing three carbons at C-5, or exchange of the pyrimidine for a purine, greatly weakens binding to the translocator. Comparison of various UDP-sugars reveals that the UDP-GlcNAc translocator has lower affinity for UDP-N-acetylgalactosamine and UDP-glucose than for its cognate substrate and therefore indicates that this translocator requires both proper stereochemistry at C-4 and an aminoacetyl group at C-2. The impact of these observations on the design of more powerful nucleoside-based inhibitors of nucleotide-sugar import is discussed.
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Walker G, Kunz D, Pignat W, Wiesenberg I, Van den Bosch H, Pfeilschifter J. Tetranactin inhibits interleukin 1 beta and cAMP induction of group II phospholipase A2 in rat renal mesangial cells. Eur J Pharmacol 1996; 306:265-70. [PMID: 8813640 DOI: 10.1016/0014-2999(96)00203-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Renal mesangial cells express secretory phospholipase A2 in response to two principal classes of activating signals that may interact in a synergistic fashion. These two groups of activators comprise inflammatory cytokines, such as interleukin 1 beta, and agents that elevate cellular levels of cAMP. Treatment of mesangial cells with tetranactin, a cyclic antibiotic produced by Streptomyces aureus with a molecular structure similar to cyclosporin A inhibits interleukin 1 beta- and cAMP-dependent group II phospholipase A2 secretion in a dose-dependent manner with IC50 values of 43 and 33 nM, respectively. However, tetranactin does not directly inhibit group II phospholipase A2 activity. Western blot analyses of mesangial cell supernatants reveal that the inhibition of phospholipase A2 activity is due to suppression of phospholipase A2 protein synthesis. This effect is preceded by the reduction of phospholipase A2 mRNA steady-state levels as shown by Northern blot analyses of total cellular RNA isolated from stimulated mesangial cells. Thus, tetranactin is a potent inhibitor of group II phospholipase A2 expression in cytokine- and cAMP-stimulated mesangial cells and represents a new class of group II phospholipase A2 inhibitors with IC50 values in the low nanomolar range. This compound may be useful in the therapy of diseases associated with increased group II phospholipase A2 secretion.
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189
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Walker G, Burgess D, Kinsey WH. Fertilization promotes selective association of the Abl [correction of AbI] kinase with the egg cytoskeleton. Eur J Cell Biol 1996; 70:165-71. [PMID: 8793389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Fertilization of the sea urchin egg is known to involve activation of a variety of protein kinases including at least one protein tyrosine kinase. In the present study, fertilization was found to stimulate the association of the Abl [correction of AbI] protein kinase with the detergent-insoluble egg cytoskeleton. Increased levels of Abl protein and of protein tyrosine kinase activity were detected in cytoskeleton preparations made as early as 5 to 15 min after insemination. Immunofluorescence localization demonstrated that the Abl kinase becomes associated primarily with the cortical cytoskeleton of the fertilized egg. A separate, 57 kDa protein tyrosine kinase did not associate with the cytoskeleton indicating that fertilization results in the selective association of the Abl kinase with the cortical cytoskeleton.
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Abstract
Twenty asymptomatic infants with cystic fibrosis (CF) were studied to determine the amount of radiolabeled aerosol [99m technetium diethylenetriamine penta acetic acid (Tc99m DTPA)] deposited in the respiratory system and its distribution. Aerosols were generated by jet nebulization systems that were used in the wards and the laboratory. Subjects were studied in three groups: group A (n = 10) was sedated with chloral hydrate; children inhaled an aerosol of 7.7 microns mass median diameter (MMD); group B (n = 5) was not sedated, using the same nebulization system (same aerosol particle size as group A); and group C (n = 5) was not sedated; these children inhaled an aerosol with an MMD of 3.6 microns. Normal saline plus 4 mCi of Tc99m bound to DTPA was added to each nebulizer. A closed system was used to collect the expired aerosol. Radioactivity in each infant and in the equipment was measured with a gamma camera on completion of nebulization. In groups A and B, the percentages of the total dose deposited in the lung were 0.97 +/- 0.35% and 0.76 +/- 0.36%, respectively. In group C, 2.0 +/- 0.71% was deposited in the lung (P < 0.01). Deposition in the nose, mouth, and pharynx was least in group C (P < 0.01). In groups A and B, the intrathoracic deposition occurred predominantly in the trachea and main bronchi, whereas in group C, significantly more aerosol was deposited in the lung region. There was marked inter-subject variability in the percentage of aerosol deposition within the three groups. There was no correlation between percentage of aerosol deposited in the respiratory system and age, height, or weight. Sedation did not have a significant effect on deposition of aerosol in infants. This study indicates that only a small proportion of nebulized solution is deposited in the lungs of infants and that this proportion is influenced by the particle size of the aerosol. The smaller particle size (3.6 microns MMD) was deposited in the lung better than large particles.
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Runciman C, Walker G, Katz C, Howell T. Equitable provision of health services to aboriginal and Torres Strait Islander people of Queensland. Aust N Z J Public Health 1996; 20:15-7. [PMID: 8799060 DOI: 10.1111/j.1467-842x.1996.tb01329.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
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192
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Kunz D, Walker G, Eberhardt W, Pfeilschifter J. Molecular mechanisms of dexamethasone inhibition of nitric oxide synthase expression in interleukin 1 beta-stimulated mesangial cells: evidence for the involvement of transcriptional and posttranscriptional regulation. Proc Natl Acad Sci U S A 1996; 93:255-9. [PMID: 8552616 PMCID: PMC40217 DOI: 10.1073/pnas.93.1.255] [Citation(s) in RCA: 111] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Inducible nitric oxide synthase (iNOS; EC 1.14.13.39) is expressed in rat glomerular mesangial cells upon exposure to the inflammatory cytokine interleukin 1 beta (IL-1 beta). We have reported that nanomolar concentrations of dexamethasone suppress IL-1 beta-induced iNOS protein expression and production of nitrite, the stable end product of NO formation, without affecting IL-1 beta-triggered increase in iNOS mRNA levels. We now have studied the mechanisms by which dexamethasone suppresses IL-1 beta-stimulated iNOS expression in mesangial cells. Surprisingly, nuclear run-on transcription experiments demonstrate that dexamethasone markedly attenuates IL-1 beta-induced iNOS gene transcription. However, this is counteracted by a prolongation of the half-life of iNOS mRNA from 1 h to 2.5 h by dexamethasone. Moreover, dexamethasone drastically reduces the amount of iNOS protein by reduction of iNOS mRNA translation and increased degradation of iNOS protein. These results indicate that glucocorticoids act at multiple levels to regulate iNOS expression, thus providing important insights into the treatment of inflammatory diseases.
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193
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Pfeilschifter J, Eberhardt W, Hummel R, Kunz D, Mühl H, Nitsch D, Plüss C, Walker G. Therapeutic strategies for the inhibition of inducible nitric oxide synthase--potential for a novel class of anti-inflammatory agents. Cell Biol Int 1996; 20:51-8. [PMID: 8936407 DOI: 10.1006/cbir.1996.0008] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
In recent years, NO, a gas previously considered a potentially toxic chemical, has become established as a diffusible universal messenger mediating cell-cell communication throughout the body. In mammals, NO is a recognized mediator of blood vessel relaxation that helps to maintain blood pressure. In the central nervous system NO acts as a non-conventional neurotransmitter and participates in the establishment of long-term plasticity required for memory formation. In addition, NO is responsible for some parts of the host response to sepsis and inflammation and contributes to certain disease states. A number of strategies have emerged with regard to a pharmacological control of pathological NO overproductions. This review will discuss these novel therapeutic approaches that may provide new means for clinical medicine.
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Lan HC, Reddy PG, Chambers MA, Walker G, Srivastava KK, Ferguson JA. Effect of stress on interleukin-2 receptor expression by bovine mononuclear leukocytes. Vet Immunol Immunopathol 1995; 49:241-9. [PMID: 8746698 DOI: 10.1016/0165-2427(95)05470-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Holstein calves given three consecutive i.m. injections of dexamethasone (DEX) (0.04 mg kg-1) showed lymphopenia and neutrophilia with increased numbers of mature neutrophils on post-injection Days 1 and 2, but these values returned to normal levels by post-injection Day 3. Interleukin-2 receptor (IL-2R) expression by peripheral blood mononuclear cells (PBMC) was evaluated by flow cytometry using a monoclonal antibody specific for bovine IL-2R alpha. Treatment with DEX significantly decreased expression of IL-2R alpha in Concanavalin A (Con A)-activated PBMC on Day 1 (P < 0.02) and on Day 2 (P < 0.1). On Day 3, expression of IL-2R alpha by PBMC was similar in control and DEX-treated calves. This decrease in IL-2R alpha expression correlated with decreased proliferative responses of PBMC to the T-cell mitogens, phytohemagglutinin (PHA) and Con A. Following in vitro treatment with recombinant human (rhu) interleukin-12 (IL-12) Con A-induced proliferative responses of PBMC tended to be higher in both groups. However, the rhu IL-12 induced increase of Con A activated proliferative responses were significantly greater in DEX-treated calves than in control calves. IL-2R alpha expression by PBMC was found to be less in calves transported 800 km in a truck as compared to that in PBMC from controls. These data suggest that stress-induced immunosuppression in calves may involve decreased IL-2R alpha expression and decreased IL-12 production. Serum chemistry results indicated a trend toward higher creatine kinase (CK) levels in DEX-treated calves. This may be due to the lysis of corticosteroid sensitive lymphocytes.
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Kunz D, Walker G, Eberhardt W, Nitsch D, Pfeilschifter J. Interleukin 1 beta-induced expression of nitric oxide synthase in rat renal mesangial cells is suppressed by cyclosporin A. Biochem Biophys Res Commun 1995; 216:438-46. [PMID: 7488131 DOI: 10.1006/bbrc.1995.2642] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The expression of inducible nitric oxide synthase (iNOS) is triggered in rat renal mesangial cells by exposure to the inflammatory cytokine interleukin 1 beta (IL-1 beta). Here we report that cyclosporin A (CsA) a potent immunosuppressive drug, inhibits IL-1 beta dependent iNOS expression in renal mesangial cells. Addition of CsA dose dependently suppresses IL-1 beta-induced nitrite formation (IC50 = 0.9 microM). Western- and Northern blot analyses of mesangial cell extracts reveal that the inhibition of IL-1 beta-induced nitrite formation by CsA is due to decreased iNOS protein and iNOS mRNA steady state levels. Using nuclear run on experiments we show that the transcription rate of the IL-1 beta-induced iNOS gene is reduced. Furthermore, by electrophoretic mobility shift analysis we demonstrate reduced DNA-binding of the nuclear factor NF kappa B, an essential component of the IL-1 beta-dependent upregulation of iNOS gene transcription. The data presented in this report suggest that the cellular machinery involved in the IL-1 beta dependent transcriptional upregulation of the iNOS gene in mesangial cells is a target for the action of CsA.
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Broom NJ, Elder JS, Hannan PC, Pons JE, O'Hanlon PJ, Walker G, Wilson J, Woodall P. The chemistry of pseudomonic acid. Part 14. Synthesis and in vivo biological activity of heterocyclyl substituted oxazole derivatives. J Antibiot (Tokyo) 1995; 48:1336-44. [PMID: 8557577 DOI: 10.7164/antibiotics.48.1336] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Semisynthetic analogues of pseudomonic acid A have been prepared containing a heterocyclyl substituted oxazole. Derivatives in which the heterocycle was thiophene, furan, pyridine, or isoxazole showed good antibacterial potency and were further evaluated in vivo. Both pharmacokinetic parameters and oral activity against an experimental intraperitoneal sepsis were superior to results obtained from previously described pseudomonic acid A derivatives.
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197
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Millward H, Bellhouse B, Walker G. Screw-thread flow promoters: an experimental study of ultrafiltration and microfiltration performance. J Memb Sci 1995. [DOI: 10.1016/0376-7388(95)00092-q] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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198
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Atkinson R, Keylon K, Odor PS, Walker G, Hunt L. Disaster nursing in the Oklahoma City bombing. INSIGHT (AMERICAN SOCIETY OF OPHTHALMIC REGISTERED NURSES) 1995; 20:30-1. [PMID: 7594916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The Oklahoma City Federal Building disaster quickly changed a routine day of eye surgical procedures into a chaotic trauma center for the victims with not only eye injuries, but multiple deep lacerations and other injuries. The devastating and disruptive effect of the bombing was stressful for the nursing staff who became disaster survivors of the emotional trauma involved.
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199
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Walker G. Supportive counseling for HIV-infected drug using women. FOCUS (SAN FRANCISCO, CALIF.) 1995; 10:1-4. [PMID: 11363031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
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200
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Walker G, Kunz D, Pignat W, van den Bosch H, Pfeilschifter J. Pyrrolidine dithiocarbamate differentially affects cytokine- and cAMP-induced expression of group II phospholipase A2 in rat renal mesangial cells. FEBS Lett 1995; 364:218-22. [PMID: 7750575 DOI: 10.1016/0014-5793(95)00402-u] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Renal mesangial cells express group II phospholipase A2 in response to two principal classes of activating signals that may interact in a synergistic fashion. These two groups of activators comprise inflammatory cytokines such as interleukin-1 beta (IL-1 beta) and tumor necrosis factor-alpha (TNF alpha) and agents that elevate cellular levels of cAMP such as forskolin, an activator of adenylate cyclase. Using pyrrolidine dithiocarbamate (PDTC), a potent inhibitor of nuclear factor NF kappa B, we determined its role in cytokine--and cAMP--triggered group II PLA2 expression. Micromolar amounts of PDTC suppress the IL-1 beta- and TNF alpha-dependent, but not the forskolin-stimulated group II PLA2 activity in mesangial cells. Furthermore, PDTC inhibited the increase of group II PLA2 mRNA steady state levels in response to IL-1 beta and TNF alpha, while only marginally affecting forskolin-induced PLA2 mRNA levels. Our data suggest that NF kappa B activation is an essential component of the cytokine signalling pathway responsible for group II PLA2 gene regulation and that cAMP triggers a separate signalling cascade not involving NF kappa B. These observations may provide a basis to study the underlying mechanisms involved in the regulation of group II PLA2 gene expression.
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