51
|
Luker KA, Austin L, Caress A, Hallett CE. The importance of 'knowing the patient': community nurses' constructions of quality in providing palliative care. J Adv Nurs 2000; 31:775-82. [PMID: 10759973 DOI: 10.1046/j.1365-2648.2000.01364.x] [Citation(s) in RCA: 177] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
This paper reports findings from a study conducted in one community health care trust where 62 members of the district nursing team (grades B-H) were interviewed. An adaptation of the critical incident technique was used to determine factors which contributed or detracted from high quality care for a number of key areas including palliative care. The centrality of knowing the patient and his/her family emerged as an essential antecedent to the provision of high quality palliative care. Factors enabling the formation of positive relationships were given prominence in descriptions of ideal care. Strategies used to achieve this included establishing early contact with the patient and family, ensuring continuity of care, spending time with the patient and providing more than the physical aspects of care. The characteristics described by the community nurses are similar to those advocated in 'new nursing' which identifies the uniqueness of patient needs, and where the nurse-patient relationship is objectified as the vehicle through which therapeutic nursing can be delivered. The link with 'new nursing' emerges at an interesting time for community nurses. The past decade has seen many changes in the way that community nursing services are configured. The work of the district nursing service has been redefined, making the ideals of new nursing, for example holism, less achievable than they were a decade ago. This study reiterates the view that palliative care is one aspect of district nursing work that is universally valued as it lends itself to being an exemplar of excellence in terms of the potential for realizing the ideals of nursing practice. This is of increasing importance in the context of changes that militate against this ideal.
Collapse
|
52
|
Hallett CE, Austin L, Caress A, Luker KA. Wound care in the community setting: clinical decision making in context. J Adv Nurs 2000; 31:783-93. [PMID: 10759974 DOI: 10.1046/j.1365-2648.2000.01348.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Sixty-two community nurses in northern England of grades B and D to H were interviewed by a team of four researchers. The interviews were semi-structured, and were tape-recorded, fully transcribed and content analysed. They were conducted as part of a larger study, the aim of which was to examine community nurses' perceptions of quality in nursing care. One of the main themes the work focused on was decision-making as an element of quality. Data relating to wound care were considered from the perspective of the insights they offered into clinical decision-making. Data were interpreted in the light of a literature review in which a distinction had been made between theories which represented clinical decision-making as a linear or staged process and those which represented it as intuitive. Within the former category, three sub-categories were suggested: theorists could be divided into 'pragmatists', 'systematisers' and those who advocated 'diagnostic reasoning'. The interpretation of the data suggested that the clinical decisions made by community nurses in the area of wound care appeared largely intuitive, yet were also closely related to 'diagnostic reasoning'. They were furthermore based on a range of sources of information and justified by a number of different types of rationale.
Collapse
|
53
|
Leong J, Hayes A, Austin L, Morrison W. Muscle protection following motor nerve repair in combination with leukemia inhibitory factor. J Hand Surg Am 1999; 24:37-45. [PMID: 10048514 DOI: 10.1053/jhsu.1999.jhsy24a0037] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Leukemia inhibitory factor (LIF) has been shown to stimulate growth of muscle and nerve cells. In this rat study, in which the nerve to the medial head of the gastrocnemius was divided and repaired and slow-release LIF was administered at the repair site, we evaluated recovery by measuring the force of muscle contraction and of muscle bulk. Thirty-five male Sprague-Dawley rats (325-375 g) were randomly divided into 5 different groups according to type of treatment: denervated, end-to-end nerve repair, end-to-end nerve repair with LIF, neurotization, and neurotization with LIF. The contralateral side served as a nonoperated control group. Leukemia inhibitory factor was administered for 28 days to the site of the nerve repair via an implanted osmotic infusion pump. Muscle mass and muscular function were evaluated at 6 weeks using electrophysiologic techniques. The medial gastrocnemius muscle mass of the repair + LIF group was greater than the repair-alone group. The peak twitch, relative twitch, relative tetanic, and tetanic forces generated from the repair + LIF group were also significantly higher than those in the repair-alone group. Although neurotization was almost as effective as end-to-end nerve repair for reinnervating muscle, LIF had no increased effect on neurotization. These data suggest that LIF protects muscular function and reduces denervation atrophy following end-to-end nerve repair.
Collapse
|
54
|
Bennett TM, Dowsing BJ, Austin L, Messina A, Nicola NA, Morrison WA. Anterograde transport of leukemia inhibitory factor within transected sciatic nerves. Muscle Nerve 1999; 22:78-87. [PMID: 9883860 DOI: 10.1002/(sici)1097-4598(199901)22:1<78::aid-mus12>3.0.co;2-i] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Disappointing functional recovery following peripheral nerve repair can be improved by neurotrophic growth factors. Leukemia inhibitory factor (LIF) is unique in that it has independent neurotrophic and myotrophic actions. The aim of this study was to explain this finding by establishing the existence of anterograde axonal transport of LIF from the site of nerve division to denervated muscles. Using 125I LIF, administered topically via an entubulation repair of divided rat sciatic nerve, we monitored its subsequent distribution by measuring the radioactivity associated with nerve segments and denervated muscles. We established that LIF preferentially accumulated in denervated muscles, a process we could reduce by 70% after tightly ligating the intervening nerve, confirming the presence of anterograde axonal transport. This was most likely an active mode of transport that ceased approximately 24 h after nerve division, establishing a narrow clinical time frame within which the myotrophic action of LIF could be optimized following nerve repair.
Collapse
|
55
|
Jenkins C, Kennedy D, Austin L, Boateng Y, Todd E, Cavanaugh C, Pakalnis A, Robinson W, Hislop D, Raine C, Stepka-Tracey C, Ellis L, Hermayer KL. Community programs and screening related to diabetes and its complications. JOURNAL OF THE SOUTH CAROLINA MEDICAL ASSOCIATION (1975) 1998; 94:493-500. [PMID: 9844315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
|
56
|
Kurek JB, Radford AJ, Crump DE, Bower JJ, Feeney SJ, Austin L, Byrne E. LIF (AM424), a promising growth factor for the treatment of ALS. J Neurol Sci 1998; 160 Suppl 1:S106-13. [PMID: 9851659 DOI: 10.1016/s0022-510x(98)00208-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Growth factors are theoretically promising agents for ALS therapy, but have been disappointing in subcutaneous delivery due to either toxicity or lack of major efficacy. Leukaemia inhibitory factor (LIF), was named after its effect on haemopoietic cells, and belongs to a group of cytokines which includes CNTF, IL-6, CT-1, OM and IL-11. All group members use the gp130 signal transducing subunit for intracellular signalling, but show differences in biological effect. In vitro and in vivo studies on axotomy and nerve crush models demonstrate a powerful effect of LIF in the survival of both motor and sensory neurones, while reducing denervation induced muscle atrophy. Its effects in muscle also include stimulating myoblast proliferation in vitro, and up-regulation after muscle injury. LIF will also stimulate muscle regeneration in vivo when applied exogenously after injury. In published studies of both axotomy induced neuronal death and in the Wobbler mouse models LIF is active at doses of 10 microg/kg delivered systemically, well below the expected maximum tolerated dose suggested by primate safety studies. LIF is expressed in low levels by spinal cord neurones with significant up-regulation when the neurones are damaged by BOAA toxin, an excitatory amino acid associated with a form of ALS. This augments other evidence suggesting LIF is a trauma factor playing a role in the injury response of adult neuronal tissue, and may be more effective than related growth factors. Taken together, the data suggests LIF is a physiologically relevant trophic factor with implications in clinical medicine as a therapy for ALS, and a human recombinant form (AM424), entered human clinical trials during 1998.
Collapse
|
57
|
Luker KA, Austin L, Hogg C, Ferguson B, Smith K. Nurse-patient relationships: the context of nurse prescribing. J Adv Nurs 1998; 28:235-42. [PMID: 9725718 DOI: 10.1046/j.1365-2648.1998.00788.x] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Nurse prescribing was initiated in the United Kingdom in October 1994 in eight demonstration sites. The evaluation of this extension to the community nurses' role explored both economic and qualitative benefits to patients, carers, nurses and other health care professionals. In this paper the impact of nurse prescribing on patients is explored. Benefits experienced by patients are described along with the difficulties encountered. The patients' views regarding nurses as prescribers are also explored. Data were collected by means of interviews with patients/carers, the focus of which was to evaluate changes associated with nurse prescribing. Patients raised a number of issues associated with their relationship with nurses. Patients valued nurses for both their accessibility and approachability, which led them to discuss health issues which would not otherwise have been brought to the attention of the general practitioner. The arguments which support the incorporation of these qualities into an expanded nursing role are presented.
Collapse
|
58
|
Kurek JB, Bennett TM, Bower JJ, Muldoon CM, Austin L. Leukaemia inhibitory factor (LIF) production in a mouse model of spinal trauma. Neurosci Lett 1998; 249:1-4. [PMID: 9672374 DOI: 10.1016/s0304-3940(98)00360-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
A model of spinal trauma was developed where spinal neurones of adult mice were exposed to the excitotoxic glutamate analogue beta-N-oxylamino-L-alanine (L-BOAA). After 24 h, the injured neurones received a single dose of [125I]-LIF at the same site of the spinal cord, and 2 h later, tissues were removed to assess the distribution of leukaemia inhibitory factor (LIF). There was a significant increase in LIF binding to the injured region of the spinal cord over saline controls, and this corresponded with a significant increase in LIF mRNA expression in the same region of the cord. There was a change in the expression of ciliary neurotrophic factor, but the expression of cardiotrophin-1 (CT-1) and the common receptor subunit LIF receptor beta (LIFRbeta) did not change after neurotoxin treatment. The results add to the evidence that LIF plays a significant role in the response of adult neuronal tissue to injury.
Collapse
|
59
|
Abstract
From October 1994 qualified district nurses and health visitors from eight demonstration sites in England have been able to prescribe from a limited list of formulary items. Data collected from nurses formed only one part of the evaluation of nurse prescribing. These data highlighted a number of areas where prescribing nurses were faced with difficult decisions. A number of authors have considered how both doctors and nurses make decisions, and the factors which may influence the decision making process. With reference to the literature this paper focuses on the findings related to decision making in the context of nurse prescribing.
Collapse
|
60
|
Kurek JB, Bower JJ, Romanella M, Koentgen F, Murphy M, Austin L. The role of leukemia inhibitory factor in skeletal muscle regeneration. Muscle Nerve 1997; 20:815-22. [PMID: 9179153 DOI: 10.1002/(sici)1097-4598(199707)20:7<815::aid-mus5>3.0.co;2-a] [Citation(s) in RCA: 103] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Although a number of cytokines have been implicated in tissue regeneration, it is unknown which ones actually function in vivo. Here, we use mice with a targeted mutation in the leukemia inhibitory factor (LIF) gene to examine the role of LIF in muscle regeneration. Using a muscle crush model, we show that muscle regeneration in LIF knockout mice is significantly, reduced compared to control littermates. Further, targeted infusion of LIF in both normal and LIF knockout animals stimulated muscle regeneration, but the stimulation observed was much greater in the mutant animals than in controls. In contrast, interleukin-6 and transforming growth factor-alpha, which also stimulate myoblast proliferation in vitro, had no effect on regeneration. These findings demonstrate directly that LIF is involved in regeneration of injured muscle and points to the use of LIF as a therapeutic agent in the treatment of neuromuscular disease.
Collapse
|
61
|
Luker K, Austin L, Hogg C, Ferguson B, Smith K. Patients' views of nurse prescribing. NURSING TIMES 1997; 93:51-4. [PMID: 9165922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
In 1994 the law was changed to allow nurses to prescribe from a limited formulary. The Department of Health commissioned research to evaluate nurse prescribing in eight pilot sites in England. This article presents part of this research. In particular, it examines how patients perceived the role of nurses and health visitors as prescribers. The study involved interviewing patients seen by community nurses before and after the introduction of nurse prescribing. The advantages patients identified coincided with the anticipated benefits, while the disadvantages that had been anticipated before the study were not confirmed. Patients were positive about nurses as prescribers and in some instances preferred nurses to doctors.
Collapse
|
62
|
Luker KA, Austin L, Willock J, Ferguson B, Smith K. Nurses' and GPs' views of the nurse prescribers' formulary. Nurs Stand 1997; 11:33-38. [PMID: 9096509 DOI: 10.7748/ns1997.02.11.22.33.c2442] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
This article presents the findings from the evaluation of nurse prescribing, undertaken in eight demonstration sites since October 1994. The authors examine in particular the nurses' prescribing behaviour and the type of items nurses and GPs would like to see added to the formulary. The opportunities for prescribing and the limitations of the formulary for health visitors and practice nurses are highlighted.
Collapse
|
63
|
Abstract
Leukaemia inhibitory factor (LIF) has been shown to effectively enhance skeletal muscle regeneration after mechanical injury and it may have potential therapeutic use in the muscular dystrophies as well as peripheral nerve repair after injury. When LIF is applied systemically to an animal, it is rapidly removed with a biological half life of only a few minutes, and at high doses it exhibits toxic effects. Calcium alginate rods have been developed for the purpose of insertion adjacent to skeletal muscles. These rods, when charged with LIF will release the growth factor to the muscle at a rate of less than 1% per day and for a period extending to several months. In addition, tubes of alginate are described which will be suitable for the continuous supply of LIF to repaired peripheral nerve.
Collapse
|
64
|
Kurek JB, Nouri S, Kannourakis G, Murphy M, Austin L. Leukemia inhibitory factor and interleukin-6 are produced by diseased and regenerating skeletal muscle. Muscle Nerve 1996; 19:1291-301. [PMID: 8808655 DOI: 10.1002/(sici)1097-4598(199610)19:10<1291::aid-mus6>3.0.co;2-9] [Citation(s) in RCA: 121] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The process of skeletal muscle regeneration following injury or disease involves locally produced growth factors which control cellular proliferation and differentiation. Leukemia inhibitory factor (LIF) and interleukin-6 (IL-6) have previously been shown to promote the proliferation of myoblasts in vitro, and thus may be involved in muscle regeneration. In the present investigation, the in vivo expression of these two myogenic growth factors was examined in regenerating muscle after a crush injury of wild type mice, and in diseased skeletal muscle and diaphragm of the mdxmouse. Using Reverse transcription polymerase chain reaction we have demonstrated that while normal muscle rarely expresses mRNA for these two molecules, there is significant up-regulation following injury, coinciding with the active period of muscle regeneration. This suggests these molecules act as locally produced trauma factors. This observation is reinforced in mdxmouse muscle, which is undergoing a cycle of degeneration and regeneration, and expresses both LIF and IL-6. Using in situ hybridization we have localized mRNA for LIF expression in the mdx diaphragm, suggesting that local production of these molecules by regenerating muscle itself, as well as by other cells in muscle, plays an important role in muscle regeneration.
Collapse
|
65
|
Kurek J, Bower J, Romanella M, Austin L. Leukaemia inhibitory factor treatment stimulates muscle regeneration in the mdx mouse. Neurosci Lett 1996; 212:167-70. [PMID: 8843099 DOI: 10.1016/0304-3940(96)12802-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
A number of growth factors are involved in coordinating muscle cell proliferation and differentiation, particularly after injury and in disease. Leukaemia inhibitory factor (LIF) strongly stimulates the proliferation of myoblasts in vitro and in vivo and its expression in muscle after injury suggests that LIF may have a role as a trauma factor. The mdx mouse was used to study the effects of LIF on in vivo muscle regeneration during disease. The rationale for using trophic factors such as LIF to treat neuromuscular disease includes the understanding that these molecules show some degree of selectivity for the population of cells in which they are effective. LIF was administered to muscle of the mdx mouse using osmotic pumps implanted subcutaneously in unrestrained mice. The growth factor was continuously delivered into the vastus lateralis muscle at 7 U/mu 1 for 7 days via a catheter. The results show that LIF increased the rate of muscle regeneration in mdx mice by stimulating the formation of larger myotubes. LIF treatment also increased the number of regenerating myotubes in the perfused area. This myotrophic action indicates that LIF contributes to muscle regeneration. Together with its known neurotrophic action, LIF is a potential therapeutic agent for the treatment of neuromuscular disease.
Collapse
|
66
|
Johnson R, Staiano-Coico L, Austin L, Cardinale I, Nabeya-Tsukifuji R, Krueger JG. PUVA treatment selectively induces a cell cycle block and subsequent apoptosis in human T-lymphocytes. Photochem Photobiol 1996; 63:566-71. [PMID: 8628746 DOI: 10.1111/j.1751-1097.1996.tb05657.x] [Citation(s) in RCA: 80] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Psoralen plus UVA (320-400 nm radiation; PUVA) is a highly effective therapy for cutaneous diseases caused by skin infiltration with normal or neoplastic T-lymphocytes. In comparing the effects of pharmacologically relevant, low-dose PUVA treatment on growth of human keratinocytes, peripheral blood leukocytes (PBMC), and T-lymphocyte cell lines, we determined that PBMC or T-lymphocytes were > 50-fold more sensitive to cytotoxic effects of PUVA, while antiproliferative effects were produced by similar PUVA levels in all cell types. Low doses of PUVA (10 ng/mL 8-methoxypsoralen and 1-2 J/cm2) were highly cytotoxic for phytohemagglutinin-activated normal lymphocytes or transformed T-lymphocytes as assessed by two viability assays and by flow cytofluorometry. Altered lymphocyte morphology, nuclear fragmentation, TUNEL+ nuclei or nuclear fragments, and the appearance of a sub-G1 DNA peak indicated that cell death occurred by apoptosis, beginning about 1 day after PUVA treatment and continuing for several days thereafter. From assessment of cell cycle progression in mimosine-synchronized cells, PUVA treatment markedly slowed cell cycle progression, eventually producing cell cycle arrest and apoptotic entry. We propose that the probable basis for disease remissions (psoriasis, cutaneous T-cell lymphoma) produced by PUVA treatment is through selective cytotoxic effects on clonal T-lymphocyte populations that are concentrated in diseased skin.
Collapse
|
67
|
Skibber JM, Soong SJ, Austin L, Balch CM, Sawaya RE. Cranial irradiation after surgical excision of brain metastases in melanoma patients. Ann Surg Oncol 1996; 3:118-23. [PMID: 8646510 DOI: 10.1007/bf02305789] [Citation(s) in RCA: 113] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND Brain metastases account for 20-54% of reported deaths from melanoma. Duration and quality of survival depend on the extent of metastatic disease and response to treatment. Treatment goals are palliation of symptoms and prolongation of life. No studies have directly compared surgery alone and surgery with adjunctive cranial irradiation in patients with solitary brain metastases. METHODS We evaluated postoperative adjunctive cranial irradiation in 34 patients with solitary brain metastases. RESULTS Overall survival was significantly improved in the 22 patients who received adjunctive cranial irradiation versus that in the 12 patients who had surgery alone. Twenty-eight patients subsequently relapsed. Nine of 10 patients with surgery alone had brain recurrence as a component of failure. Six of 10 patients not receiving irradiation had brain recurrences as a component of relapse at multiple sites whereas only 1 of 18 patients receiving irradiation relapsed with the brain. CONCLUSIONS Adjunctive cranial irradiation is justified for melanoma patients who undergo surgical therapy for solitary brain metastases. Survival in patients presenting with solitary brain metastases was improved by a reduction of relapse in the brain as a component of failure by combined surgery and irradiation.
Collapse
|
68
|
Kurek JB, Austin L, Cheema SS, Bartlett PF, Murphy M. Up-regulation of leukaemia inhibitory factor and interleukin-6 in transected sciatic nerve and muscle following denervation. Neuromuscul Disord 1996; 6:105-14. [PMID: 8664561 DOI: 10.1016/0960-8966(95)00029-1] [Citation(s) in RCA: 116] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Leukaemia inhibitory factor (LIF) and Interleukin-6 (IL-6) are multifunctional cytokines that are related on the basis of their predicted structural similarities and shared signal transducing receptor components. Both these factors stimulate myoblast proliferation, and whereas LIF is neurotrophic for sensory neurons, and for the motor neurons which innervate muscle, IL-6 has only been reported to act on a population of septal neurons in the brain. We have looked at the effect of peripheral nerve trauma on the expression of these factors. We show here that whereas LIF and IL-6 mRNAs are expressed in low levels in normal sciatic nerve and skeletal muscle, there is significant up-regulation in the nerve segments after injury, with proximally and distally. There is also an increase in LIF and IL-6 expression in the denervated muscle located largely in the muscle cells. In addition, while there is retrograde axonal transport of LIF by the sciatic nerve, IL-6 is not retrogradely transported, and as a result, IL-6 does not stimulate the survival of sensory neurons in vitro. Both growth factors are produced by Schwann cells. These results show a rapid response in the expression of these genes after injury and suggest that LIF and IL-6 act as trauma factors but with different roles in injured peripheral nerve.
Collapse
|
69
|
Vakakis N, Bower J, Austin L. In vitro myoblast to myotube transformations in the presence of leukemia inhibitory factor. Neurochem Int 1995; 27:329-35. [PMID: 8845733 DOI: 10.1016/0197-0186(95)00014-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Leukemia inhibitory factor (LIF) is a pleiotropic cytokine which exerts a variety of effects on many cell types including neuronal cells, and is a potent mitogen for myoblasts. At concentrations of 0.1-0.3 ng/ml, the peptide stimulates a maximal increase in cell number. LIF initiates a prolonged proliferative response lasting up to 13 days, when myoblasts are exposed to it in culture. LIF expression can be detected in vivo during development of limb muscle and in adult regenerating skeletal muscle tissue. Here, we studied the levels of expression of alpha-bungarotoxin-binding sites as a measure of acetylcholine receptors (AChRs), myosin light chain pattern and rate of myotube formation in fused, control and LIF-treated muscle cultures derived from mouse hind-limb muscles. We found that both the level of expression of AChRs and myosin light chain pattern, are normal, following exposure of the cells to LIF. There was no difference in the rate of myotube formation between LIF-stimulated and control myoblasts over a 10-fold concentration range (0.3-3.0 ng/ml) as determined by nuclei counts. Taken together, these results suggest that LIF, in combination with other cytokines, may act in vivo to stimulate rapid growth, without significant differentiation, during the early phases of myogenesis.
Collapse
|
70
|
Bower J, Vakakis N, Nicola NA, Austin L. Specific binding of leukemia inhibitory factor to murine myoblasts in culture. J Cell Physiol 1995; 164:93-8. [PMID: 7790402 DOI: 10.1002/jcp.1041640112] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Leukemia inhibitory factor (LIF) is a member of the cytokine family of growth factors. It has been shown to exert a variety of actions on a diverse range of cell types, including neuronal, bone, and hemopoietic cells (Hilton, 1992, Trends Biochem. Sci., 17:72-76). In many of these cell types, studies have indicated the presence of specific receptors for LIF (Godard et al., 1982, J. Biol. Chem., 267: 3214-3222; Hilton et al., Proc. Natl. Acad. Sci. USA, 85:5971-5975; Hilton and Nicola, 1992, J. Biol. Chem., 267:10238-10247.). The mechanism by which these receptors act is believed to involve tyrosine phosphorylation and the signal transducing receptor component gp130. We have previously shown that LIF is capable of inducing both human and murine myoblasts to proliferate in culture (Austin et al., 1992, J. Neurol. Sci., 112:185-191). We now report that LIF binds specifically to receptors on the surface of myoblasts, with an equilibrium dissociation constant of 400 pM and the number of receptors per cell varies with cell density. Binding competition studies showed that LIF binding to these receptor sites was not competed for by a number of other growth factors which stimulate myoblast proliferation including basic fibroblast growth factor (bFGF), transforming growth factor-alpha (TGF alpha), insulin-like growth factor 1 (IGF-1), and interleukin-6 (IL-6). There was a time and concentration-dependent down-regulation of receptor numbers following preincubation of myoblasts with LIF. The processing of these receptors subsequent to binding, involves as a first step, internalization and degradation by the myoblast. LIF appeared to stimulate myoblast proliferation rather than cell survival.
Collapse
|
71
|
Letsou GV, Austin L, Grandjean PA, Braxton JH, Elefteriades JA. Dynamic cardiomyoplasty. Cardiol Clin 1995; 13:121-4. [PMID: 7796426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Dynamic cardiomyoplasty is a promising new technique that appears to effect symptomatic improvement in patients with NYHA class III heart failure. Objective improvement in systolic performance of the left ventricle appears small but remains to be further defined. No survival advantage has yet been realized, although this may be seen as the technique is further refined and operative risk curtailed. Mechanism of action may include a girdling effect that prevents progressive left ventricular dilatation. This effect may be independent of any role in augmenting systolic performance. Randomized clinical trials currently in progress will provide definitive answers within the next few years to these important questions.
Collapse
|
72
|
Barnard W, Bower J, Brown MA, Murphy M, Austin L. Leukemia inhibitory factor (LIF) infusion stimulates skeletal muscle regeneration after injury: injured muscle expresses lif mRNA. J Neurol Sci 1994; 123:108-13. [PMID: 8064301 DOI: 10.1016/0022-510x(94)90211-9] [Citation(s) in RCA: 105] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Leukemia inhibitory factor (LIF) is known to stimulate myoblast growth in culture via direct receptor mediated mechanisms, but it does not suppress myoblast fusion in vitro. We show here that LIF is also effective in vivo, using a muscle crush model. Administration of LIF to the site of the crush results in an increased rate of regeneration of the injured muscle. LIF stimulates an increase in the size of the muscle fibers rather than an increase in total number. Perfusion of 125I-labelled LIF (125I-LIF) at the site of the crush leads to uptake of the great majority of 125I-LIF into the muscle, which suggests that LIF is acting directly at the site of injury. Further, following crush injury LIF mRNA synthesis commences in the muscle. These data provide evidence that LIF is acting as a natural trauma factor in vivo and is actively involved in muscle regeneration.
Collapse
|
73
|
Austin L, Fry C, Shropshire C. Mandatory education: a successful, creative approach. JOURNAL OF NURSING STAFF DEVELOPMENT : JNSD 1993; 9:200-1. [PMID: 8366379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
|
74
|
Austin L, Bower J, Kurek J, Vakakis N. Effects of leukaemia inhibitory factor and other cytokines on murine and human myoblast proliferation. J Neurol Sci 1992; 112:185-91. [PMID: 1469431 DOI: 10.1016/0022-510x(92)90149-f] [Citation(s) in RCA: 99] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
It has been shown previously that leukaemia inhibitory factor (LIF) and transforming growth factor-alpha (TGF-alpha) stimulate proliferation of primary cultures of murine myoblasts. We now show that human myoblasts respond in a similar manner to LIF and TGF-alpha. These responses occur over a range of growth conditions. There are total additive effects in both human and murine myoblasts between LIF and TGF-alpha and LIF and fibroblast growth factor-beta (FGF-beta), but not between LIF and interleukin-6 (IL-6) or insulin-like growth factor 1 (IGF-1). The LIF response is initiated by a short exposure to the cytokine and is maintained for prolonged periods in its absence.
Collapse
|
75
|
Austin L, Watterson JG, Hearn MT. Regenerating neurons. Changes in protein phosphorylation. Mol Neurobiol 1992; 6:87-93. [PMID: 1476677 DOI: 10.1007/bf02780545] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We have been studying the phosphorylation of proteins of both normal and regenerating superior cervical ganglia of the rat. Here we report the incorporation of radioactive phosphate into proteins of ganglia homogenates incubated with 32P-labeled ATP under various conditions at day 3 after postganglionic axotomy. The proteins were analyzed by two-dimensional electrophoresis followed by autoradiography. Incubation in the presence of Ca2+ or Ca2+ plus cyclic AMP produced only about 20 spots corresponding to distinctly labeled proteins. This number was reduced to about five under EGTA plus cyclic AMP conditions, whereas the presence of EGTA alone suppressed the phosphorylation reaction almost totally. All these proteins fell within the narrow pI range of 4-6, whereby no qualitative differences between regenerating and control cases were observed. However, the growth-associated protein, variously designated GAP-43, B-50, F-1, and pp-46, had enhanced levels of phosphate incorporation in regenerating ganglia compared to controls. Injury also caused consistently higher levels of phosphorylation of proteins running in the position of alpha- and beta-tubulin. Since these three proteins are major constituents of regenerating axons, these results suggest that the changes in their phosphorylation induced by injury may be involved in the regulation of their transport.
Collapse
|