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Witt BJ, Thomas RJ, Roger VL. Cardiac rehabilitation after myocardial infarction: a review to understand barriers to participation and potential solutions. EUROPA MEDICOPHYSICA 2005; 41:27-34. [PMID: 16175768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
As survival after myocardial infarction (MI) improves, secondary prevention is becoming increasingly important. Cardiac rehabilitation (CR) is one modality for delivery of secondary prevention, whose ultimate goal is to help patients receive appropriate preventive therapies that will help them optimize health and reduce the risk of future cardiac diseases. However, participation rates in CR are less than optimal: in the United States, only 29.5% of MI survivors participated, in Japan 21% of those with acute MI, and in Australia 29% of those eligible were referred, and only 1/3 of those referred acutally attended CR; moreover, there does not appear to be a trend towards increasing participation over time. After reviewing the components of CR and the benefits of participation, this paper will focus on the barriers to participation in CR: from a theoretical framework to consider barriers at patient, provider, health system, and societal levels. We then explore the possible solutions to overcome them and finally propose recommendation for future research.
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Thomas RJ, Rosen BR, Stern CE, Weiss JW, Kwong KK. Functional imaging of working memory in obstructive sleep-disordered breathing. J Appl Physiol (1985) 2005; 98:2226-34. [PMID: 15677733 DOI: 10.1152/japplphysiol.01225.2004] [Citation(s) in RCA: 167] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Functional magnetic resonance imaging was used to map cerebral activation in 16 patients with obstructive sleep-disordered breathing (OSDB) and 16 healthy subjects, during the performance of a 2-back verbal working memory task. Six patients with OSDB were reimaged after a minimum period of 8 wk of treatment with positive airway pressure. Working memory speed in OSDB was significantly slower than in healthy subjects, and a group average map showed absence of dorsolateral prefrontal activation, regardless of nocturnal hypoxia. After treatment, resolution of subjective sleepiness contrasted with no significant change in behavioral performance, persistent lack of prefrontal activation, and partial recovery of posterior parietal activation. These findings suggest that working memory may be impaired in OSDB and that this impairment is associated with disproportionate impairment of function in the dorsolateral prefrontal cortex. Nocturnal hypoxia may not be a necessary determinant of cognitive dysfunction, and sleep fragmentation may be sufficient. There may be dissociations between respiratory vs. cortical recovery and objective vs. subjective recovery. Hypofrontality may provide a plausible biological mechanism for a clinical overlap with disorders of mood and attention.
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Marples NM, Kelly DJ, Thomas RJ. PERSPECTIVE: THE EVOLUTION OF WARNING COLORATION IS NOT PARADOXICAL. Evolution 2005. [DOI: 10.1554/04-448] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Lopez-Jimenez F, Malinski M, Gutt M, Sierra-Johnson J, Wady Aude Y, Rimawi AA, Mego PA, Thomas RJ, Allison TG, Kirby B, Hughes-Borst B, Somers VK. Recognition, diagnosis and management of obesity after myocardial infarction. Int J Obes (Lond) 2004; 29:137-41. [PMID: 15520829 DOI: 10.1038/sj.ijo.0802831] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE We investigated the documentation of obesity as a medical problem, and subsequent management recommendations, in patients after myocardial infarction (MI). DESIGN We performed a cross-sectional analysis of a randomly selected sample of 627 patients discharged after an MI, from five US teaching hospitals between 1/1/01 and 12/31/02. Information was extracted from clinical notes using standardized definitions. RESULTS Mean body mass index (BMI) was 31+/-13 kg/m2, which was documented in only 14% of patients and had to be calculated post hoc in the rest. Waist circumference and waist/hip ratio were not documented at all; 83% of patients were overweight, 55% obese, and 8% morbidly obese. In only 20% of patients with BMI> or =30 kg/m2 was the diagnosis of obesity documented either as a current medical problem, as part of past medical history or as a final diagnosis. A dietary counseling was carried out in 61% of patients with BMI> or =25 kg/m2 and in 61% of patients with BMI<25 kg/m2, P=0.96. Weight loss was described as part of the goals/plan at discharge in 7% of overweight and 9% of obese patients. There was no change in either the level of recognition of obesity (22 vs 19%, P=0.3) or in the proportion of obese patients for whom weight loss was described as part of the goals/plan at discharge (8 vs 10%, P=0.7) before (n=301) compared to after (n=326) the Call to Action in Obesity by the Surgeon General in December 2001. CONCLUSION Obesity is underecognized, underdiagnosed and undertreated in persons with acute MI.
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Abstract
PURPOSE OF REVIEW In recent years, understanding of the mechanisms by which sleep is maintained and the consequences of abnormal arousal from sleep has improved rapidly. This review describes the recent insights into the nature of sleep and arousal and the particular insights gained in common disease states such as sleep-disordered breathing. RECENT FINDINGS Expansion of the definitions of the classic stages of non-REM and REM sleep to include consideration of the role of cyclic alternating pattern sleep as a gating mechanism for arousal and maintenance of stable sleep has led to a significant advancement in understanding the nature of normal and pathologic arousals from sleep. In addition, the effect of arousals from sleep on cerebral cortical electrophysiology and autonomic activation has been further defined, with a potential effect on clinical practice. SUMMARY Arousal from sleep is dependent on wake-promoting influences overwhelming forces promoting sleep. Autonomic activation and cortical arousal can significantly affect and destabilize sleep homeostasis. The understanding of sleep-respiration interactions continues to evolve. The definition of the minimal arousal event is an important research goal. It will be important in clinical practice and research to consider sleep stability domains as a complement to sleep depth staging to allow better understanding of the relative stability and instability of the system and to consider all components of the consequences of arousal.
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Chinivasagam HN, Thomas RJ, Casey K, McGahan E, Gardner EA, Rafiee M, Blackall PJ. Microbiological status of piggery effluent from 13 piggeries in the south east Queensland region of Australia. J Appl Microbiol 2004; 97:883-91. [PMID: 15479402 DOI: 10.1111/j.1365-2672.2004.02382.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIMS To assist in the development of safe piggery effluent re-use guidelines by determining the level of selected pathogens and indicator organisms in the effluent ponds of 13 south-east Queensland piggeries. METHODS AND RESULTS The numbers of thermotolerant coliforms, Campylobacter jejuni/coli, Erysipelothrix rhusiopathiae, Escherichia coli, Salmonella and rotavirus were determined in 29 samples derived from the 13 piggeries. The study demonstrated that the 13 final effluent ponds contained an average of 1.2 x 10(5) colony-forming units (CFU) 100 ml(-1) of thermotolerant coliforms and 1.03 x 10(5) CFU 100 ml(-1) of E. coli. The Campylobacter level varied from none detectable (two of 13 piggeries) to a maximum of 930 most probable number (MPN) 100 ml(-1) (two of 13 piggeries). Salmonella was detected in the final ponds of only four of the 13 piggeries and then only at a low level (highest level being 51 MPN 100 ml(-1)). No rotavirus and no Erysip. rhusiopathiae were detected. The average log10 reductions across the ponding systems to the final irrigation pond were 1.77 for thermotolerant coliforms, 1.71 for E. coli and 1.04 for Campylobacter. CONCLUSIONS This study has provided a baseline knowledge on the levels of indicator organisms and selected pathogens in piggery effluent. SIGNIFICANCE AND IMPACT OF THE STUDY The knowledge gained in this study will assist in the development of guidelines to ensure the safe and sustainable re-use of piggery effluent.
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Thomas RJ, Bartlett LA, Marples NM, Kelly DJ, Cuthill IC. Prey selection by wild birds can allow novel and conspicuous colour morphs to spread in prey populations. OIKOS 2004. [DOI: 10.1111/j.0030-1299.2004.13089.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Cain CP, Thomas RJ, Noojin GD, Stolarski DJ, Kennedy PK, Buffington GD, Rockwell BA. Sub-50-fs laser retinal damage thresholds in primate eyes with group velocity dispersion, self-focusing and low-density plasmas. Graefes Arch Clin Exp Ophthalmol 2004; 243:101-12. [PMID: 15241612 DOI: 10.1007/s00417-004-0924-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2003] [Revised: 02/12/2004] [Accepted: 03/02/2004] [Indexed: 10/26/2022] Open
Abstract
BACKGROUND In vivo retinal injury studies using sub-50-femtosecond laser pulses in the near-infrared must consider nonlinear effects such as group velocity dispersion (GVD), self-focusing, laser-induced breakdown (LIB) and low-density plasmas (LDPs). In this paper we present the results of our theoretical calculations of nonlinear effects and our experimental measurements for the visible lesion thresholds in live eyes. We compare these values with the measured LIB and LDP thresholds in an artificial eye. All three thresholds were measured with and without pre-chirping the input pulse to compensate for GVD effects. METHODS We recorded the minimum visible lesion (MVL) thresholds in vivo for sub-50-fs laser pulses, with and without pre-chirping the input pulses. In addition, we measured the LIB and LDP thresholds, with and without pre-chirping, within an artificial eye. Different degrees of pre-chirping were required to give optimal compensation for GVD in the live eye and the artificial eye. Probit analysis was used on all data, and comparisons among thresholds were made, to determine the effects on the three thresholds of chirp compensation for GVD. RESULTS Results of our nonlinear modeling and calculations for GVD compensation, self-focusing, LIB, and low-density plasmas were compared with our experimental results using live eyes and the artificial eye. The damage threshold in live eyes dropped in energy from 0.25 microJ, for the flat-phase input, to 0.17 microJ when optimally chirped pulses were used, while the LIB threshold was reduced from 0.29 microJ to 0.19 microJ with optimally chirped pulses. The LDP threshold dropped from 0.21 microJ to 0.14 microJ with the pre-chirped pulse. At 44 fs, these energies produced peak powers at least twice the calculated critical power that produces nonlinear self-focusing and beam collapse, for propagation of non-aberrated gaussian beams in a uniform medium. CONCLUSIONS Based on our measurements of the MVL thresholds, with and without GVD compensation, we conclude that the visible lesion thresholds produced by 44 fs pulses in rhesus eyes are increased in energy due to GVD. The MVL ED50 was reduced by one third when the pulse was pre-chirped to compensate for GVD in the eye. This reduction in amplitude also holds true in the artificial eye for the LIB ED50 bubble thresholds and the LDP ED50 plasma channels, when using pre-chirped pulses versus non-chirped pulses. We also conclude from the data presented that low-density plasmas, and not LIB cavitation bubbles, are the probable mediating factor at the visible lesion thresholds observed within live eyes, for pulse durations at and below 50 fs. Therefore, the plasma channel created by LDPs is the major damage mechanism, if not the only damage mechanism, at MVL threshold energies for these pulse durations.
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Thomas RJ, Goodbourne C, Goldie B. The transmission of MRSA via orthopaedic marking pens--fact or fiction. Ann R Coll Surg Engl 2004; 86:51-2. [PMID: 15032207 PMCID: PMC1964032 DOI: 10.1308/003588404772614731] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Rittig MG, Shaw B, Letley DP, Thomas RJ, Argent RH, Atherton JC. Helicobacter pylori-induced homotypic phagosome fusion in human monocytes is independent of the bacterial vacA and cag status. Cell Microbiol 2004; 5:887-99. [PMID: 14641174 DOI: 10.1046/j.1462-5822.2003.00328.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Following reports that a VacA+cag+ toxigenic but not a VacA-cag- non-toxigenic Helicobacter pylori strain induced homotypic phagosome fusion in murine macrophages, we addressed that phenomenon in human cells. Mononuclear phagocytes and epitheloid cells were challenged with H. pylori strains of different vacA and cag genotypes and with VacA- and Cag- isogenic mutants, and chased in the absence or presence of signal transduction modulators. Electron microscopy revealed that, in monocytes: (i) homotypic phagosome fusion was frequently induced by all live H. pylori strains investigated but not by exogenous VacA; (ii) phagosomes containing bacteria fused, but not those containing latex beads; (iii) fusion resulted in communal compartments resembling giant multivesicular bodies; and (iv) formation of these compartments was blocked by inhibiting the host cell regulators PI 3-kinase, phospholipase C and p42 MAP kinase. Whereas some internalized bacteria remained viable 1 h after uptake, none survived a 24 h period. In contrast to monocytes, infected epitheloid cells rarely developed communal compartments. In combination, these results demonstrate that, in human monocytes, the H. pylori-induced homotypic phagosome fusion depends on neither the vacuolating cytotoxin VacA nor the cag pathogenicity island of H. pylori and does not result in prolonged intracellular survival.
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Thomas RJ, Terzano MG, Parrino L, Weiss JW. Obstructive Sleep-disordered Breathing with a Dominant Cyclic Alternating Pattern—a Recognizable Polysomnographic Variant with Practical Clinical Implications. Sleep 2004; 27:229-34. [PMID: 15124715 DOI: 10.1093/sleep/27.2.229] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVES To define the clinical and polysomnographic features of a distinct variant of obstructive sleep-disordered breathing that is remarkably mild during rapid eye movement (REM) sleep. DESIGN Observational study and evaluation of polysomnographic and clinical records. SETTING American Academy of Sleep Medicine-accredited multidisciplinary sleep disorders center and laboratory. PATIENTS 35 medication-free subjects with clinical and polysomnographic severe obstructive sleep-disordered breathing selected for dominance of 1 of 2 disordered breathing patterns. INTERVENTIONS Positive airway pressure titration. MEASUREMENTS AND RESULTS Nasal pressure was used to score respiratory events. Sleep was scored by both the standard criteria and cyclic alternating pattern (CAP), and the distribution of respiratory events was tabulated and analyzed. A distinct clinical and polysomnographic syndrome emerged, CAP-dominant sleep-disordered breathing, characterized by severe relatively short cycle obstructive events during non-REM sleep that were mild in REM sleep. Characteristics include lower body mass index, fewer apneas, and a lower hypoxic burden as reflected by frequency and severity of nocturnal oxygen saturation. During positive pressure titration, a remarkable respiratory instability emerged selectively during CAP, in contrast to stability during REM sleep. This partial treatment failure was associated with persistent clinical symptoms. CONCLUSIONS This variant of sleep apnea may reflect a dominant component of respiratory instability and periodic breathing coupled with upper-airway obstruction. Its existence questions the conventional practice of calculating global respiratory indexes. Besides positive airway pressure, measures to treat periodic breathing may be required.
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Turner JW, Thomas RJ, Reinsch NL. Willingness to Try a New Communication Technology: Perceptual Factors and Task Situations in a Health Care Context. ACTA ACUST UNITED AC 2004. [DOI: 10.1177/0021943603259584] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Thomas RJ, Kwong K. Computational neuroanatomy in sleep-disordered breathing and related disorders. Sleep Med 2003; 4:379-80. [PMID: 14592277 DOI: 10.1016/s1389-9457(03)00163-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Bebb JR, Letley DP, Thomas RJ, Aviles F, Collins HM, Watson SA, Hand NM, Zaitoun A, Atherton JC. Helicobacter pylori upregulates matrilysin (MMP-7) in epithelial cells in vivo and in vitro in a Cag dependent manner. Gut 2003; 52:1408-13. [PMID: 12970131 PMCID: PMC1773843 DOI: 10.1136/gut.52.10.1408] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND AND AIMS Matrix metalloproteinase-7 (MMP-7) is important in normal and pathological remodelling of epithelial-matrix interactions, and is upregulated in gastric cancer. Helicobacter pylori infection is the first stage in gastric carcinogenesis, and therefore our aim was to determine if H pylori upregulated gastric MMP-7 expression and if this was affected by strain virulence. METHODS We took gastric biopsy specimens at endoscopy from H pylori infected (n = 17) and uninfected (n = 18) patients and assessed MMP-7 expression by ELISA, real time polymerase chain reaction (PCR), and immunohistochemistry (concentrating on epithelial cells in the proliferative zone). We PCR typed H pylori for cagE and vacA. We performed H pylori/cell line coculture studies with wild-type pathogenic and non-pathogenic H pylori strains and with CagE(-) and VacA(-) isogenic mutants. RESULTS Gastric biopsy specimens from H pylori+ patients expressed higher levels of MMP-7 at the protein and mRNA levels in the antrum and corpus (for example, by ELISA: H pylori+ 0.182 OD units vH pylori- 0.059; p = 0.009 antrum). Epithelial cells from H pylori+ patients stained more intensely for MMP-7 than those from uninfected patients, including in the proliferative zone containing pluripotent cells (p<0.03 antrum, p<0.04 body). Upregulation of MMP-7 in epithelial cells was confirmed at the protein and mRNA levels by H pylori/cell line coculture. These experiments also showed that MMP-7 upregulation was dependent on an intact H pyloricag pathogenicity island but not on the vacuolating cytotoxin. CONCLUSION We speculate that increased expression of MMP-7 in H pylori gastritis may contribute to gastric carcinogenesis.
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Thomas RJ, Williams M, Garcia-Vargas J. Lessons learned from raltitrexed--quality assurance, patient education and intensive supportive drugs to optimise tolerability. Clin Oncol (R Coll Radiol) 2003; 15:227-32. [PMID: 12924450 DOI: 10.1016/s0936-6555(03)00092-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Although recent trials have raised concerns about the toxicity of raltitrexed monotherapy in patients with advanced colorectal cancer (aCRC), similar concerns have also been raised with other chemotherapy regimens in aCRC. The lessons learnt form our previous experiences with raltitrexed are, therefore, still important as they offer practical guidances to optimise tolerability of chemotherapy for CRC in general. The aims of the study were to report the low-toxicity profile in 58 patients receiving raltitrexed when a rigorous patient information and education strategy was implemented together with an intensive supportive adjuvant drugs regimen from the start. After a discussion with the consultant, all patients received a further consultation with a specialist nurse, a series of bespoke information tools, including an information video and written guidelines on how to avoid, prevent and deal promptly with the side-effects of raltitrexed. They all received intravenous adjuvant ondansetron and dexamethasone, then oral domperidone, ranitidine and nystatin from cycle one. The dose intensity was 98% over 307 cycles. Toxicity associated with raltitrexed comprised grade 1/2 diarrhoea (31.6% of treatment cycles), nausea (12.4%) and vomiting (8.4%), with no grade 3/4 events; grade 1/2 alopecia (17.9%); grade 1 (only) stomatitis (2.3%) and grade 1/2/3 lethargy (70.3%, only 2.3% grade 3), anaemia (14.3%, only 0.3% grade 3) and neutropenia (3.3%, only 0.3% grade 3). There were no treatment-related deaths. The low toxicity, despite high-dose intensity, suggests that intensive supportive education and drugs should have a role in the future design of regimens containing raltitrexed and other chemotherapy regimens for colorectal carcinoma.
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Philp AJ, Phillips WA, Rockman SP, Vincan E, Baindur-Hudson S, Burns W, Valentine R, Thomas RJ. Microsatellite instability in gastrointestinal tract tumours. INTERNATIONAL JOURNAL OF SURGICAL INVESTIGATION 2003; 2:267-74. [PMID: 12678528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Abstract
Although a number of studies have documented microsatellite instability (MSI) in gastrointestinal tumours, the clinical significance is uncertain. In this study the MSI status and clinicopathological features were examined in gastric and colorectal tumours. Eighty-four gastrointestinal tumours were examined for MSI. Normal and tumour DNA isolated from the same patients were analysed at five different microsatellite loci. Clinical features of these patients were also collated and compared with MSI status. High level MSI (MSI-H) (as defined by instability in 2 or more microsatellites) was detected in 6 out of 47 (13%) colon tumours and 6 of 37 (16%) gastric tumours. The frequency of MSI-H between these groups was not statistically significant (P = 0.36). There was no significant correlation with patient age or gender, UICC stage, or degree of differentiation of the tumour. This was true both when analysed as a group, as well as when divided into colon and gastric sites. Our results confirm that a proportion of sporadic tumours from the colon and stomach exhibit an MSI-H phenotype. However, there was no significant relationship between the presence of MSI and any of the clinicopathological characteristics studied.
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Thomas RJ, Noojin GD, Stolarski DJ, Hall RT, Cain CP, Toth CA, Rockwell BA. A comparative study of retinal effects from continuous wave and femtosecond mode-locked lasers. Lasers Surg Med 2003; 31:9-17. [PMID: 12124709 DOI: 10.1002/lsm.10067] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND AND OBJECTIVES In order to provide a direct comparison of the effects of mode-locked systems to those with continuous-wave (CW) or nonpulsed output, we have performed an experiment with lasers possessing otherwise identical output characteristics. This in vivo minimum visible lesion study compares retinal effects of mode-locked and CW lasers complete with histopathology of the treated areas. STUDY DESIGN/MATERIALS AND METHODS Titanium:Sapphire lasers produced 800-nm output for either mode-locked (76 MHz repetition rate, 120 femtoseconds) or CW exposures. Alternating CW and mode-locked laser exposures were delivered to the paramacular retinal region of rhesus subjects. Laser exposure duration was set to one-quarter second for both types of exposures. Through ophthalmoscopic examination of the fundus, a minimal visible lesion (MVL) threshold for damage was established. RESULTS Approximately 75 test sites for each type of exposure were examined. The laser dosage thresholds and 95% confidence intervals for minimal visible damage at 24 hours postexposure were found to be 5.9 mJ (5.23-6.6 mJ) and 5.84 mJ (5.23-6.58 mJ) for mode-locked and CW exposures, respectively. CONCLUSIONS Results are compared with published studies conducted at similar exposures. These nearly identical damage thresholds indicate a primarily thermal tissue damage mechanism. Comparative histopathology of acute and chronic lesions of both exposure types is also presented.
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Bennis WG, Thomas RJ. Crucibles of leadership. HARVARD BUSINESS REVIEW 2002; 80:39-124. [PMID: 12227145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
What makes a great leader? Why do some people appear to know instinctively how to inspire employees--bringing out their confidence, loyalty, and dedication--while others flounder again and again? No simple formula can explain how great leaders come to be, but Bennis and Thomas believe it has something to do with the ways people handle adversity. The authors' recent research suggests that one of the most reliable indicators and predictors of true leadership is the ability to learn from even the most negative experiences. An extraordinary leader is a kind of phoenix rising from the ashes of adversity stronger and more committed than ever. In interviewing more than 40 leaders in business and the public sector over the past three years, the authors discovered that all of them--young and old alike--had endured intense, often traumatic, experiences that transformed them and became the source of their distinctive leadership abilities. Bennis and Thomas call these shaping experiences "crucibles," after the vessels medieval alchemists used in their attempts to turn base metals into gold. For the interviewees, their crucibles were the points at which they were forced to question who they were and what was important to them. These experiences made them stronger and more confident and changed their sense of purpose in some fundamental way. Through a variety of examples, the authors explore the idea of the crucible in detail. They also reveal that great leaders possess four essential skills, the most critical of which is "adaptive capacity"--an almost magical ability to transcend adversity and emerge stronger than before.
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Cain CP, Toth CA, Noojin GD, Stolarski DJ, Thomas RJ, Rockwell BA. Thresholds for retinal injury from multiple near-infrared ultrashort laser pulses. HEALTH PHYSICS 2002; 82:855-62. [PMID: 12046758 DOI: 10.1097/00004032-200206000-00014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Multiple-pulse lasers are routinely used in the laboratory for research, manufacturing, medical procedures, and in military applications. In order to provide a safe work environment for personnel using these lasers, safety standards have been established and have been in use for many years. These safety standards have addressed laser pulses of nanosecond duration and longer. Recently, safety standards have been updated to address laser pulses as short as 100 femtoseconds in duration. In order to tie these "ultrashort" laser pulses to hazard trends in currently established standards for multiple-pulse exposures with repetition rates less than several kilohertz, this experiment was conducted. Reported herein are minimum visible lesion thresholds in the paramacula of the primate retina using an 800-nm wavelength laser with 1,000 pulses per second, at 130 femtoseconds (fs) pulse duration. The minimum visible lesion (MVL) thresholds were determined at 1 h and 24 h post exposure for 1, 10, 100, 1,000, and 10,000 pulses and are compared with thresholds reported by other researchers. These new data are evaluated relative to the current safety standards for retinal exposure limits as a function of the number of pulses for femtosecond-pulse duration. Data from this study show that the retinal ED50 thresholds/pulse in the paramacula decrease by almost a factor of four as the number of pulses goes from one to ten and then decrease very little for an increase of three decades more in the number of pulses. The MVL-ED50 at the threshold decreased from 0.55 microJ for a single pulse to 0.15 microJ/pulse for 10 pulses and then only to 0.11 microJ/pulse for 10,000 pulses.
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Guise TA, Yin JJ, Thomas RJ, Dallas M, Cui Y, Gillespie MT. Parathyroid hormone-related protein (PTHrP)-(1-139) isoform is efficiently secreted in vitro and enhances breast cancer metastasis to bone in vivo. Bone 2002; 30:670-6. [PMID: 11996903 DOI: 10.1016/s8756-3282(02)00685-3] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Parathyroid hormone-related peptide (PTHrP) is a mediator of local osteolysis due to breast cancer. Three isoforms of PTHrP, (1-139), (1-141), and (1-173), are products of alternative splicing in humans, but the specific contribution of each of these isoforms to osteolytic metastasis caused by breast cancer has not been evaluated. To determine the role of PTHrP isoforms in breast cancer metastasis to bone, the human breast cancer cell line MDA-MB-231 (MDA-231) was stably transfected with cDNAs for human prepro PTHrP-(1-139), -(1-141), or -(1-173). Stable MDA/PTHrP-(1-139) clones expressed more PTHrP mRNA and secreted more PTHrP protein, compared with MDA/PTHrP-(1-141), -(1-173), or parental MDA-231. Parental MDA-231 cells and clones expressing each isoform had similar growth rates in vitro. In a mouse model of bone metastases, the osteolytic lesion area of radiographs was greatest in mice bearing MDA/PTHrP-(1-139) compared with those bearing MDA/PTHrP-(1-141), -(1-173), or parental MDA-231. Ca(++) and plasma PTHrP concentrations were significantly higher in the MDA/PTHrP-(1-139) compared with the MDA/PTHrP-(1-141), -(1-173), or parental MDA-231 groups. These data demonstrate that the PTHrP-(1-139) isoform was produced to a greater extent than PTHrP-(1-141) or -(1-173), and in vivo enhanced osteolysis with increased plasma PTHrP concentrations and hypercalcemia compared with overexpression of PTHrP-(1-141) or -(1-173).
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Leeaphon M, Rohl K, Thomas RJ, Fanwick PE, Walton RA. Reactions of the polyhydride complex ReH7(PPh3)2 with quinoline, 2-hydroxyquinoline, and 2-mercaptoquinoline. The preparation and characterization of hydrido complexes of rhenium(V) and chloro complexes of rhenium(III). Inorg Chem 2002. [DOI: 10.1021/ic00076a024] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Thomas RJ, Long FA. Hydrogen Exchange of Azulenes. IV. The Acid-Catalyzed Detritiation of Azulene-1-t and Guaiazulene-3-t. J Am Chem Soc 2002. [DOI: 10.1021/ja01076a009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Bender ML, Thomas RJ. The Concurrent Alkaline Hydrolysis and Isotopic Oxygen Exchange of a Series of p-Substituted Methyl Benzoates1,2. J Am Chem Soc 2002. [DOI: 10.1021/ja01481a022] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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