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Herbert KJ, Puliyadi R, Prevo R, Rodriguez-Berriguete G, Ryan A, Ramadan K, Higgins GS. Targeting TOPK sensitises tumour cells to radiation-induced damage by enhancing replication stress. Cell Death Differ 2021; 28:1333-1346. [PMID: 33168956 PMCID: PMC8027845 DOI: 10.1038/s41418-020-00655-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 10/22/2020] [Accepted: 10/22/2020] [Indexed: 01/04/2023] Open
Abstract
T-LAK-originated protein kinase (TOPK) overexpression is a feature of multiple cancers, yet is absent from most phenotypically normal tissues. As such, TOPK expression profiling and the development of TOPK-targeting pharmaceutical agents have raised hopes for its future potential in the development of targeted therapeutics. Results presented in this paper confirm the value of TOPK as a potential target for the treatment of solid tumours, and demonstrate the efficacy of a TOPK inhibitor (OTS964) when used in combination with radiation treatment. Using H460 and Calu-6 lung cancer xenograft models, we show that pharmaceutical inhibition of TOPK potentiates the efficacy of fractionated irradiation. Furthermore, we provide in vitro evidence that TOPK plays a hitherto unknown role during S phase, showing that TOPK depletion increases fork stalling and collapse under conditions of replication stress and exogenous DNA damage. Transient knockdown of TOPK was shown to impair recovery from fork stalling and to increase the formation of replication-associated single-stranded DNA foci in H460 lung cancer cells. We also show that TOPK interacts directly with CHK1 and Cdc25c, two key players in the checkpoint signalling pathway activated after replication fork collapse. This study thus provides novel insights into the mechanism by which TOPK activity supports the survival of cancer cells, facilitating checkpoint signalling in response to replication stress and DNA damage.
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Affiliation(s)
- Katharine J Herbert
- MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford, OX3 7DQ, UK
| | - Rathi Puliyadi
- MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford, OX3 7DQ, UK
| | - Remko Prevo
- MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford, OX3 7DQ, UK
| | - Gonzalo Rodriguez-Berriguete
- MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford, OX3 7DQ, UK
| | - Anderson Ryan
- MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford, OX3 7DQ, UK
| | - Kristijan Ramadan
- MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford, OX3 7DQ, UK
| | - Geoff S Higgins
- MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford, OX3 7DQ, UK.
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Herbert KJ, Ashton TM, Prevo R, Pirovano G, Higgins GS. T-LAK cell-originated protein kinase (TOPK): an emerging target for cancer-specific therapeutics. Cell Death Dis 2018; 9:1089. [PMID: 30356039 PMCID: PMC6200809 DOI: 10.1038/s41419-018-1131-7] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 10/03/2018] [Accepted: 10/08/2018] [Indexed: 12/17/2022]
Abstract
'Targeted' or 'biological' cancer treatments rely on differential gene expression between normal tissue and cancer, and genetic changes that render tumour cells especially sensitive to the agent being applied. Problems exist with the application of many agents as a result of damage to local tissues, tumour evolution and treatment resistance, or through systemic toxicity. Hence, there is a therapeutic need to uncover specific clinical targets which enhance the efficacy of cancer treatment whilst minimising the risk to healthy tissues. T-LAK cell-originated protein kinase (TOPK) is a MAPKK-like kinase which plays a role in cell cycle regulation and mitotic progression. As a consequence, TOPK expression is minimal in differentiated cells, although its overexpression is a pathophysiological feature of many tumours. Hence, TOPK has garnered interest as a cancer-specific biomarker and biochemical target with the potential to enhance cancer therapy whilst causing minimal harm to normal tissues. Small molecule inhibitors of TOPK have produced encouraging results as a stand-alone treatment in vitro and in vivo, and are expected to advance into clinical trials in the near future. In this review, we present the current literature pertaining to TOPK as a potential clinical target and describe the progress made in uncovering its role in tumour development. Firstly, we describe the functional role of TOPK as a pro-oncogenic kinase, followed by a discussion of its potential as a target for the treatment of cancers with high-TOPK expression. Next, we provide an overview of the current preclinical progress in TOPK inhibitor discovery and development, with respect to future adaptation for clinical use.
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Affiliation(s)
- Katharine J Herbert
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford, OX3 7DQ, UK.
| | - Thomas M Ashton
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford, OX3 7DQ, UK
| | - Remko Prevo
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford, OX3 7DQ, UK
| | - Giacomo Pirovano
- Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, NY, USA
| | - Geoff S Higgins
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford, OX3 7DQ, UK
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Prevo R, Pirovano G, Puliyadi R, Herbert KJ, Rodriguez-Berriguete G, O’Docherty A, Greaves W, McKenna WG, Higgins GS. CDK1 inhibition sensitizes normal cells to DNA damage in a cell cycle dependent manner. Cell Cycle 2018; 17:1513-1523. [PMID: 30045664 PMCID: PMC6132956 DOI: 10.1080/15384101.2018.1491236] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 07/01/2018] [Accepted: 06/13/2018] [Indexed: 12/15/2022] Open
Abstract
Cyclin-dependent kinase 1 (CDK1) orchestrates the transition from the G2 phase into mitosis and as cancer cells often display enhanced CDK1 activity, it has been proposed as a tumor specific anti-cancer target. Here we show that the effects of CDK1 inhibition are not restricted to tumor cells but can also reduce viability in non-cancer cells and sensitize them to radiation in a cell cycle dependent manner. Radiosensitization by the specific CDK1 inhibitor, RO-3306, was determined by colony formation assays in three tumor lines (HeLa, T24, SQ20B) and three non-cancer lines (HFL1, MRC-5, RPE). Initial results showed that CDK1 inhibition radiosensitized tumor cells, but did not sensitize normal fibroblasts and epithelial cells in colony formation assays despite effective inhibition of CDK1 signaling. Further investigation showed that normal cells were less sensitive to CDK1 inhibition because they remained predominantly in G1 for a prolonged period when plated in colony formation assays. In contrast, inhibiting CDK1 a day after plating, when the cells were going through G2/M phase, reduced their clonogenic survival both with and without radiation. Our finding that inhibition of CDK1 can damage normal cells in a cell cycle dependent manner indicates that targeting CDK1 in cancer patients may lead to toxicity in normal proliferating cells. Furthermore, our finding that cell cycle progression becomes easily stalled in non-cancer cells under normal culture conditions has general implications for testing anti-cancer agents in these cells.
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Affiliation(s)
- Remko Prevo
- Department of Oncology, Cancer Research UK/MRC Oxford Institute for Radiation Oncology, Gray Laboratories, University of Oxford, Oxford, UK
| | - Giacomo Pirovano
- Department of Oncology, Cancer Research UK/MRC Oxford Institute for Radiation Oncology, Gray Laboratories, University of Oxford, Oxford, UK
| | - Rathi Puliyadi
- Department of Oncology, Cancer Research UK/MRC Oxford Institute for Radiation Oncology, Gray Laboratories, University of Oxford, Oxford, UK
| | - Katharine J. Herbert
- Department of Oncology, Cancer Research UK/MRC Oxford Institute for Radiation Oncology, Gray Laboratories, University of Oxford, Oxford, UK
| | - Gonzalo Rodriguez-Berriguete
- Department of Oncology, Cancer Research UK/MRC Oxford Institute for Radiation Oncology, Gray Laboratories, University of Oxford, Oxford, UK
| | - Alice O’Docherty
- Department of Oncology, Cancer Research UK/MRC Oxford Institute for Radiation Oncology, Gray Laboratories, University of Oxford, Oxford, UK
| | - William Greaves
- Department of Oncology, Cancer Research UK/MRC Oxford Institute for Radiation Oncology, Gray Laboratories, University of Oxford, Oxford, UK
| | - W. Gillies McKenna
- Department of Oncology, Cancer Research UK/MRC Oxford Institute for Radiation Oncology, Gray Laboratories, University of Oxford, Oxford, UK
| | - Geoff S. Higgins
- Department of Oncology, Cancer Research UK/MRC Oxford Institute for Radiation Oncology, Gray Laboratories, University of Oxford, Oxford, UK
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Pirovano G, Ashton TM, Herbert KJ, Bryant RJ, Verrill CL, Cerundolo L, Buffa FM, Prevo R, Harrap I, Ryan AJ, Macaulay V, McKenna WG, Higgins GS. TOPK modulates tumour-specific radiosensitivity and correlates with recurrence after prostate radiotherapy. Br J Cancer 2017; 117:503-512. [PMID: 28677687 PMCID: PMC5558685 DOI: 10.1038/bjc.2017.197] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Revised: 05/10/2017] [Accepted: 06/02/2017] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Tumour-specific radiosensitising treatments may enhance the efficacy of radiotherapy without exacerbating side effects. In this study we determined the radiation response following depletion or inhibition of TOPK, a mitogen-activated protein kinase kinase family Ser/Thr protein kinase that is upregulated in many cancers. METHODS Radiation response was studied in a wide range of cancer cell lines and normal cells using colony formation assays. The effect on cell cycle progression was assessed and the relationship between TOPK expression and therapeutic efficacy was studied in a cohort of 128 prostate cancer patients treated with radical radiotherapy. RESULTS TOPK knockdown did not alter radiation response in normal tissues, but significantly enhanced radiosensitivity in cancer cells. This result was recapitulated in TOPK knockout cells and with the TOPK inhibitor, OTS964. TOPK depletion altered the G1/S transition and G2/M arrest in response to radiation. Furthermore, TOPK depletion increased chromosomal aberrations, multinucleation and apoptotic cell death after irradiation. These results suggest a possible role for TOPK in the radiation-induced DNA damage checkpoints. These findings have clinical relevance, as elevated TOPK protein expression was associated with poorer clinical outcomes in prostate cancer patients treated with radical radiotherapy. CONCLUSIONS This study demonstrates that TOPK disruption may cause tumour-specific radiosensitisation in multiple different tumour types.
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Affiliation(s)
- Giacomo Pirovano
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Thomas M Ashton
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Katharine J Herbert
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Richard J Bryant
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
- Nuffield Department of Surgical Sciences, Oxford Cancer Research Centre, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Clare L Verrill
- Nuffield Department of Surgical Sciences, Oxford Cancer Research Centre, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Lucia Cerundolo
- Nuffield Department of Surgical Sciences, Oxford Cancer Research Centre, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Francesca M Buffa
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Remko Prevo
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Iona Harrap
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Anderson J Ryan
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Valentine Macaulay
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - William G McKenna
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Geoff S Higgins
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
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Herbert KJ, Holloway A, Cook AL, Chin SP, Snow ET. Arsenic exposure disrupts epigenetic regulation of SIRT1 in human keratinocytes. Toxicol Appl Pharmacol 2014; 281:136-45. [PMID: 25281835 DOI: 10.1016/j.taap.2014.09.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [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: 07/09/2014] [Revised: 09/09/2014] [Accepted: 09/22/2014] [Indexed: 02/08/2023]
Abstract
Arsenic is an environmental toxin which increases skin cancer risk for exposed populations worldwide; however the underlying biomolecular mechanism for arsenic-induced carcinogenesis is complex and poorly defined. Recent investigations show that histone deacetylase and DNA methyltransferase activity is impaired, and epigenetic patterns of gene regulation are consistently altered in cancers associated with arsenic exposure. Expression of the histone deacetylase SIRT1 is altered in solid tumours and haematological malignancies; however its role in arsenic-induced pathology is unknown. In this study we investigated the effect of arsenic on epigenetic regulation of SIRT1 and its targeting microRNA, miR-34a in primary human keratinocytes. Acetylation of histone H4 at lysine 16 (H4K16) increased in keratinocytes exposed to 0.5μM arsenite [As(III)]; and this was associated with chromatin remodelling at the miR-34a promoter. Moreover, although SIRT1 protein initially increased in these As(III)-exposed cells, after 24days expression was not significantly different from untreated controls. Extended exposure to low-dose As(III) (0.5μM; >5weeks) compromised the pattern of CpG methylation at SIRT1 and miR-34a gene promoters, and this was associated with altered expression for both genes. We have found that arsenic alters epigenetic regulation of SIRT1 expression via structural reorganisation of chromatin at the miR-34a gene promoter in the initial 24h of exposure; and over time, through shifts in miR-34a and SIRT1 gene methylation. Taken together, this investigation demonstrates that arsenic produces cumulative disruptions to epigenetic regulation of miR-34a expression, and this is associated with impaired coordination of SIRT1 functional activity.
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Affiliation(s)
- Katharine J Herbert
- School of Health Sciences, University of Tasmania, Launceston, TAS 7250, Australia
| | - Adele Holloway
- Menzies Research Institute Tasmania, University of Tasmania, Hobart, TAS 7000, Australia
| | - Anthony L Cook
- School of Health Sciences, University of Tasmania, Launceston, TAS 7250, Australia
| | - Suyin P Chin
- Menzies Research Institute Tasmania, University of Tasmania, Hobart, TAS 7000, Australia
| | - Elizabeth T Snow
- School of Health Sciences, University of Tasmania, Launceston, TAS 7250, Australia.
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Herbert KJ, Cook AL, Snow ET. SIRT1 modulates miRNA processing defects in p53-mutated human keratinocytes. J Dermatol Sci 2014; 74:142-9. [DOI: 10.1016/j.jdermsci.2014.01.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Revised: 01/17/2014] [Accepted: 01/20/2014] [Indexed: 12/21/2022]
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Herbert KJ, Cook AL, Snow ET. SIRT1 inhibition restores apoptotic sensitivity in p53-mutated human keratinocytes. Toxicol Appl Pharmacol 2014; 277:288-97. [PMID: 24726431 DOI: 10.1016/j.taap.2014.04.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Revised: 03/17/2014] [Accepted: 04/01/2014] [Indexed: 12/27/2022]
Abstract
Mutations to the p53 gene are common in UV-exposed keratinocytes and contribute to apoptotic resistance in skin cancer. P53-dependent activity is modulated, in part, by a complex, self-limiting feedback loop imposed by miR-34a-mediated regulation of the lysine deacetylase, SIRT1. Expression of numerous microRNAs is dysregulated in squamous and basal cell carcinomas; however the contribution of specific microRNAs to the pathogenesis of skin cancer remains untested. Through use of RNAi, miRNA target site blocking oligonucleotides and small molecule inhibitors, this study explored the influence of p53 mutational status, SIRT1 activity and miR-34a levels on apoptotic sensitivity in primary (NHEK) and p53-mutated (HaCaT) keratinocyte cell lines. SIRT1 and p53 are overexpressed in p53-mutated keratinocytes, whilst miR-34a levels are 90% less in HaCaT cells. HaCaTs have impaired responses to p53/SIRT1/miR-34a axis manipulation which enhanced survival during exposure to the chemotherapeutic agent, camptothecin. Inhibition of SIRT1 activity in this cell line increased p53 acetylation and doubled camptothecin-induced cell death. Our results demonstrate that p53 mutations increase apoptotic resistance in keratinocytes by interfering with miR-34a-mediated regulation of SIRT1 expression. Thus, SIRT1 inhibitors may have a therapeutic potential for overcoming apoptotic resistance during skin cancer treatment.
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Affiliation(s)
- Katharine J Herbert
- School of Health Sciences, University of Tasmania, Launceston, TAS 7250, Australia
| | - Anthony L Cook
- School of Health Sciences, University of Tasmania, Launceston, TAS 7250, Australia.
| | - Elizabeth T Snow
- School of Health Sciences, University of Tasmania, Launceston, TAS 7250, Australia.
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8
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Herbert KJ, Snow ET. Modulation of arsenic-induced epidermal growth factor receptor pathway signalling by resveratrol. Chem Biol Interact 2012; 198:38-48. [PMID: 22634503 DOI: 10.1016/j.cbi.2012.05.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Revised: 05/15/2012] [Accepted: 05/15/2012] [Indexed: 01/12/2023]
Abstract
Arsenic (As) is both a human carcinogen and an effective anticancer drug. These aspects of arsenic toxicity develop as a consequence of arsenic-induced oxidative stress and modifications to signal pathway activity which alter gene expression. Resveratrol (RVL) a food antioxidant found in grapes and other fruits, exhibits anti-carcinogenic properties by reducing oxidative stress and restoring signal pathway control. This study investigated the impact of RVL on arsenite [As(III)]-induced cell signalling in HaCaT keratinocytes by assaying phosphorylation status of epidermal growth factor receptor (EGFR) signalling intermediates and measuring changes in expression of Phase II and DNA repair biomarkers. As(III) exposure produced dose-dependent toxicity which was associated with increased activation of EGFR pathway intermediates, cSrc, Rac1 and extracellular signal-regulated kinases 1 and 2 (ERK1/2). Arsenic-mediated ERK1/2 activation negatively regulated DNA polymerase beta expression and up regulated heme-oxygenase-1 at toxic concentrations. RVL treatment modulated As(III)-mediated ERK1/2 activation by shifting the balance of cSrc regulatory domain phosphorylation. These effects significantly altered the response of the EGFR pathway to growth factor-induced stimulation. Our research provides evidence that treatment with pharmacologically relevant doses of RVL influences cellular responses to As(III), largely due to RVL-mediated changes to Src and ERK1/2 activation.
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Affiliation(s)
- Katharine J Herbert
- School of Human Life Sciences, University of Tasmania, Launceston TAS 7248, Australia
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Morrison CM, Thompson NW, Herbert KJ, Brennen MD. Missed injuries in the acutely traumatised hand. Ulster Med J 2003; 72:22-5. [PMID: 12868699 PMCID: PMC2475407] [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] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
A prospective study of 500 consecutive patients referred from accident and emergency departments in Northern Ireland with acute hand injuries was performed to assess the incidence of missed injuries. An injury was 'missed' if a patient was receiving inappropriate treatment or returned due to persistent symptoms despite being examined, treated and discharged. There were 16 (3.2%) missed injuries. Seven involved tendon only, four were isolated nerve injuries and four were mixed tendon and nerve injuries. The remaining case was a ruptured ulnar collateral ligament of the thumb metacarpophalangeal joint. Thirteen injuries were open, with a glass laceration being the most common mechanism of injury. The time to detection of a missed injury was on average 11 days (range 1-62 days). Missed hand injuries in Northern Ireland are uncommon but do occur. A thorough clinical examination and accurate injury documentation remain fundamental in their prevention.
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Affiliation(s)
- C M Morrison
- The Northern Ireland Plastic and Maxillofacial Service, The Ulster Hospital, Upper Newtownards Road, Dundonald, Belfast BT16 1RH
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Thompson NW, Mockford BJ, Rasheed T, Herbert KJ. Functional absence of flexor digitorum superficialis to the little finger and absence of palmaris longus--is there a link? J Hand Surg Br 2002; 27:433-4. [PMID: 12367540 DOI: 10.1054/jhsb.2002.0797] [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] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We examined 150 men and 150 women aged 18-40 years to assess flexor digitorum superficialis function to the little finger and the incidence of palmaris longus absence. All patients had flexor digitorum superficialis function to the little finger assessed by standard and modified tests. The presence or absence of palmaris longus was assessed by clinical inspection. Following modified testing, ten subjects (14 hands) displayed absolute superficialis deficiency to the little finger. Forty-nine subjects had unilateral absence of palmaris longus (16%). This tendon was absent bilaterally in 26 subjects (9%). On combining the clinical findings, one subject had unilateral absence of flexor digitorum superficialis function to the little finger with contralateral absence of palmaris longus, and one subject had bilateral absence of flexor digitorium superficialis function with unilateral absence of palmaris longus. We conclude that there is no link between an absent little finger flexor digitorium superficialis and an absent palmaris longus.
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Affiliation(s)
- N W Thompson
- Northern Ireland Plastic and Maxillo-facial Service, Ulster Hospital, Dundonald, 700 Upper Newtownards Road, Belfast, Northern Ireland, UK.
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Herbert KJ, Hickey MJ, Lepore DA, Knight KR, Morrison WA, Stewart AG. Effects of the endothelin receptor antagonist Bosentan on ischaemia/reperfusion injury in rat skeletal muscle. Eur J Pharmacol 2001; 424:59-67. [PMID: 11470261 DOI: 10.1016/s0014-2999(01)01133-5] [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: 11/25/2022]
Abstract
We examined the role of endothelin in ischaemia/reperfusion injury in skeletal muscle, using the endothelin receptor antagonist Bosentan. In the rat hindlimb tourniquet ischaemia model, one hindlimb was rendered ischaemic for 2 h at 36 degrees C, then blood flow was re-established for either 24 h to assess muscle survival or 1.5 h for a study of capillary perfusion. In the first set of rats, the gastrocnemius muscle was removed from the postischaemic limb and assessed for viability histochemically using the nitro blue tetrazolium stain. Tissue water content (a measure of oedema) and myeloperoxidase activity (a measure of neutrophil accumulation) were also assessed in the ischaemic muscle, the contralateral non-ischaemic muscle and the lungs. In the second set of rats, the hind limb was infused with India ink after 2-h ischaemia and 1.5-h reperfusion and the muscle was harvested, fixed and cleared. In control rats, muscle viability was 17+/-2% (S.E.M.). In rats treated with Bosentan (10 mg/kg, i.p.) 30 min before release of the tourniquet, muscle viability (48+/-7%) was significantly increased compared to the control group (P<0.01). Bosentan treatment had no significant effect on tissue water content or myeloperoxidase activity in the ischaemic muscle, the contralateral non-ischaemic muscle or the lung. Immunoreactive endothelin levels in serum increased to a peak at 90 min of reperfusion and returned to control levels by 24-h reperfusion. India ink studies demonstrated a significantly increased functional capillary density in postischaemic Bosentan-treated muscles compared with postischaemic control muscles (P<0.05). These results suggest that endothelin plays an important role in the necrosis which results from a period of ischaemia and reperfusion in skeletal muscle, by mediating a decrease in postischaemic microvascular perfusion.
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Affiliation(s)
- K J Herbert
- Bernard O'Brien Institute of Microsurgery, St Vincent's Hospital Melbourne, 42 Fitzroy Street, Fitzroy, Victoria 3065, Australia
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Abstract
A case of iatrogenic atlantoaxial subluxation after bilateral otoplasty is presented. Cineradiography was required for definitive diagnosis. Bed rest and Halter traction successfully resolved the condition. Great care is required while turning the head during skin preparation, draping, planning, and surgery, especially in young children. A high index of suspicion is necessary when a child develops torticollis after otoplasty.
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Affiliation(s)
- E J Kelly
- Department of Plastic Surgery, Cork University Hospital, Ireland
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Abstract
A retrospective study of 50 patients (25 male, 25 female) suffering from chondrodermatitis nodularis chronica is presented. There was equal distribution between male and female, with the nodule being situated on the helix in 36 cases (23 male, 13 female), and on the antihelix in 18 cases (4 male, 14 female). Four patients had bilateral lesions. All the patients complained of severe pain in the affected ear when they slept on it at night. Of the 54 ears in this study, 23 had undergone previous surgery for the complaint. These recurrences occurred when either skin alone, or a disproportionately large piece of skin relative to cartilage, was excised. A treatment technique is described involving minimal skin excision combined with extensive cartilage resection. There has been no recurrence following our technique and postoperative deformity has been minimal.
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Affiliation(s)
- D A Munnoch
- Department of Plastic Surgery, Dundee Royal Infirmary, UK
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Abstract
Anatomical studies of the deltoid muscle were performed on 16 cadaver shoulders. The anatomy of the axillary nerve, the vascular pedicles, and the musculocutaneous perforators was assessed. These studies confirmed that part of the deltoid muscle can be used as a vascularised flap to cover defects of the shoulder while leaving some viable functioning muscle intact. We report the use of hemideltoid flaps to treat chronic radionecrotic ulcers involving the shoulders of two patients. In the first, the posterior part of the muscle was used as a local muscle flap. In the second, the anterior part of the muscle was raised with overlying skin to form a musculocutaneous flap. The flaps remained healed at one year follow-up. These soft tissue radionecrotic defects over the shoulder are an uncommon late complication of radiotherapy for breast cancer. Pedicled or free flaps are now recognised as the preferred methods of treatment.
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Affiliation(s)
- D A Munnoch
- Department of Plastic Surgery, Dundee Royal Infirmary, UK
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Abstract
A method of continuously assessing peroperative blood loss is presented. A calibrated trap which collects all the blood loss is placed in the suction tubing. Bipolar diathermy and suction maintain a bloodless wound. A test using 20 ml of fresh venous blood showed that approximately 5 ml remained clotted in the tubing and 15 ml entered the trap. The method is particularly applicable to cleft lip and palate surgery.
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Affiliation(s)
- K J Herbert
- Department of Plastic Surgery, Leicester Royal Infirmary
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