Carcinogenicity of ethylene oxide: key findings and scientific issues

In support of the Integrated Risk Information System (IRIS), the U.S. Environmental Protection Agency (EPA) completed an evaluation of the inhalation carcinogenicity of ethylene oxide (EtO) in December 2016. This article reviews key findings and scientific issues regarding the carcinogenicity of EtO in EPA's Carcinogenicity Assessment. EPA's assessment critically reviewed and characterized epidemiologic, laboratory animal, and mechanistic studies pertaining to the human carcinogenicity of EtO, and addressed some key scientific issues such as the analysis of mechanistic data as part of the cancer hazard evaluation and to inform the quantitative risk assessment. The weight of evidence from the epidemiologic, laboratory animal, and mechanistic studies supports a conclusion that EtO is carcinogenic in humans, with the strongest human evidence linking EtO exposure to lymphoid and breast cancers. Analyses of the mechanistic data establish a key role for genotoxicity and mutagenicity in EtO-induced carcinogenicity and reveal little evidence supporting other mode-of-action hypotheses. In conclusion, EtO was found to be carcinogenic to humans by inhalation, posing a potential human health hazard for lymphoid and breast cancers.

Muscle Quality Improves with Extended High-Intensity Resistance Training after Hip Fracture

BACKGROUND

Muscle mass deficits endure after hip fracture. Strategies to improve muscle quality may improve mobility and physical function. It is unknown whether training after usual care yields muscle quality gains after hip fracture.

OBJECTIVES

To determine whether muscle quality improves after hip fracture with high-intensity resistance training and protein supplementation.

DESIGN

Case series.

SETTING

University of Utah Skeletal Muscle Exercise Research Facility.

PARTICIPANTS

17 community-dwelling older adults, 3.6+/-1.1 months post-hip fracture, recently discharged from usual-care physical therapy (mean age 77.0+/-12.0 years, 12 female), enrolled.

INTERVENTION

Participants underwent 12 weeks (3x/week) of unilaterally-biased resistance training.

METHODS/MATERIALS

Participants were measured via a 3.0 Tesla whole-body MR imager for muscle lean and intramuscular adipose tissue (IMAT) of the quadriceps before and after resistance training. Peak isometric knee extension force output was measured with an isokinetic dynamometer. Muscle quality was calculated by dividing peak isometric knee extension force (N) by quadriceps lean muscle mass (cm2). In addition, common physical function variables were measured before and after training.

RESULTS

Surgical and nonsurgical lean quadriceps muscle mass improved among participants (mean change: 2.9 cm2+/-1.4 cm2, and 2.7 cm2+/-1.3 cm2, respectively), while IMAT remained unchanged. Peak force improved in the surgical limb by 43.1+/-23N, with no significant change in the nonsurgical limb. Significant gains in physical function were evident after training.

CONCLUSION

Participants recovering from hip fracture demonstrated improvements in muscle mass, muscle strength, and muscle quality in the surgical limb after hip fracture. These were in addition to gains made in the first months after fracture with traditional care. Future studies should determine the impact that muscle quality has on long-term functional recovery in this population.

High-Intensity Multimodal Resistance Training Improves Muscle Function, Symmetry during a Sit-to-Stand Task, and Physical Function Following Hip Fracture

OBJECTIVES

Post rehabilitation, older adults with hip fracture display low vertical ground reaction force (vGRF) on the involved lower extremity during a sit-to-stand task and low physical function. The purpose of this study was to test whether muscle performance, involved side vGRF during a sit-to-stand task, and physical function improved following multimodal high-intensity resistance training, when initiated after usual care (2 to 6 months after hip fracture).

DESIGN

Case series study, 12 weeks extended high-intensity strength training intervention following hip fracture.

SETTING

University hospital outpatient facility.

PARTICIPANTS

Twenty-four community-dwelling older adults (mean age 78.4 years (SD 10.4), 16 female/8 male), 3.6 (SD 1.2) months post-hip fracture and discharged from physical therapy participated. Intervention/Measurement: All participants performed sit-to-stand tasks, muscle performance tests, and modified physical performance test (mPPT) before and after 12 weeks (3x/wk) of training. Variables were compared using paired t-tests.

RESULTS

The vGRF rate of force development (RFD) and magnitude of discrepancy between limb loading during rising phase of sit-to-stand task (AREA) variables improved post-training (RFD ratio = Pre: 0.78 - Post: 0.82, AREA ratio = Pre: 0.79 - Post: 0.86). Surgical leg extension power gains were large (~65%) while strength gains were moderate (~34%); yielding improved symmetry in both strength (Pre: 0.74 - Post: 0.88) and power (Pre: 0.75 - Post: 0.82). Physical function improved pre-training 25 (SD 5.2) to post training 30 (SD 4.3), (p < 0.001).

CONCLUSION

Unique to this study, participants recovering from hip fracture demonstrated improved symmetry in sit-to-stand vGRFs, muscle function, and physical function after training. However, a high percentage of patients continued to experience persistently low vGRF of the involved side compared to previous studies of healthy elderly controls. Developing alternative strategies to improve involved side vGRF may be warranted.

Exercise, manual therapy, and use of booster sessions in physical therapy for knee osteoarthritis: a multi-center, factorial randomized clinical trial

OBJECTIVE

(1) Do treatment effects differ between participants receiving manual therapy (MT) with exercise compared to subjects who don't, (2) are treatment effects sustained better when participants receive booster sessions compared to those who don't over a one year period in subjects with knee osteoarthritis (KOA)?

DESIGN

Multi-center, 2 × 2 factorial randomized clinical trial. 300 participants with knee OA were randomized to four groups: exercise-no boosters (Ex), exercise-with boosters (Ex+B), manual therapy+exercise-no boosters (MT+Ex), manual therapy+exercise-with boosters (MT+Ex+B). The primary outcome was the Western Ontario and McMaster osteoarthritis index (WOMAC) at 1 year. Secondary outcomes included knee pain, physical performance tests, and proportions of participants meeting treatment responder criteria.

RESULTS

There were no differences between groups on the WOMAC at 1 year or on any performance-based measures. Secondary analyses indicated a) better scores on the WOMAC and greater odds of being a treatment responder at 9 weeks for participants receiving MT, b) greater odds of being a treatment responder at 1 year for participants receiving boosters. Exploratory interaction analysis suggested knee pain decreases for participants receiving boosters and increases for participants not receiving boosters from 9 weeks to 1 year.

CONCLUSIONS

MT or use of boosters with exercise did not result in additive improvement in the primary outcome at 1 year. Secondary outcomes suggest MT may have some short term benefit, and booster sessions may improve responder status and knee pain at 1 year. However, the role of booster sessions remains unclear in sustaining treatment effects and warrants further study.

CLINICAL TRIALS

gov (NCT01314183).

Key Characteristics of Carcinogens as a Basis for Organizing Data on Mechanisms of Carcinogenesis

BACKGROUND

A recent review by the International Agency for Research on Cancer (IARC) updated the assessments of the > 100 agents classified as Group 1, carcinogenic to humans (IARC Monographs Volume 100, parts A-F). This exercise was complicated by the absence of a broadly accepted, systematic method for evaluating mechanistic data to support conclusions regarding human hazard from exposure to carcinogens.

OBJECTIVES AND METHODS

IARC therefore convened two workshops in which an international Working Group of experts identified 10 key characteristics, one or more of which are commonly exhibited by established human carcinogens.

DISCUSSION

These characteristics provide the basis for an objective approach to identifying and organizing results from pertinent mechanistic studies. The 10 characteristics are the abilities of an agent to 1) act as an electrophile either directly or after metabolic activation; 2) be genotoxic; 3) alter DNA repair or cause genomic instability; 4) induce epigenetic alterations; 5) induce oxidative stress; 6) induce chronic inflammation; 7) be immunosuppressive; 8) modulate receptor-mediated effects; 9) cause immortalization; and 10) alter cell proliferation, cell death, or nutrient supply.

CONCLUSION

We describe the use of the 10 key characteristics to conduct a systematic literature search focused on relevant end points and construct a graphical representation of the identified mechanistic information. Next, we use benzene and polychlorinated biphenyls as examples to illustrate how this approach may work in practice. The approach described is similar in many respects to those currently being implemented by the U.S. EPA's Integrated Risk Information System Program and the U.S. National Toxicology Program.

CITATION

Smith MT, Guyton KZ, Gibbons CF, Fritz JM, Portier CJ, Rusyn I, DeMarini DM, Caldwell JC, Kavlock RJ, Lambert P, Hecht SS, Bucher JR, Stewart BW, Baan R, Cogliano VJ, Straif K. 2016. Key characteristics of carcinogens as a basis for organizing data on mechanisms of carcinogenesis. Environ Health Perspect 124:713-721; http://dx.doi.org/10.1289/ehp.1509912.

Depletion of tumor-associated macrophages slows the growth of chemically induced mouse lung adenocarcinomas

Chronic inflammation is a risk factor for lung cancer, and low-dose aspirin intake reduces lung cancer risk. However, the roles that specific inflammatory cells and their products play in lung carcinogenesis have yet to be fully elucidated. In mice, alveolar macrophage numbers increase as lung tumors progress, and pulmonary macrophage programing changes within 2 weeks of carcinogen exposure. To examine how macrophages specifically affect lung tumor progression, they were depleted in mice bearing urethane-induced lung tumors using clodronate-encapsulated liposomes. Alveolar macrophage populations decreased to ≤50% of control levels after 4–6 weeks of liposomal clodronate treatment. Tumor burden decreased by 50% compared to vehicle treated mice, and tumor cell proliferation, as measured by Ki67 staining, was also attenuated. Pulmonary fluid levels of insulin-like growth factor-I, CXCL1, IL-6, and CCL2 diminished with clodronate liposome treatment. Tumor-associated macrophages expressed markers of both M1 and M2 programing in vehicle and clodronate liposome-treated mice. Mice lacking CCR2 (the receptor for macrophage chemotactic factor CCL2) had comparable numbers of alveolar macrophages and showed no difference in tumor growth rates when compared to similarly treated wild-type mice suggesting that while CCL2 may recruit macrophages to lung tumor microenvironments, redundant pathways can compensate when CCL2/CCR2 signaling is inactivated. Depletion of pulmonary macrophages rather than inhibition of their recruitment may be an advantageous strategy for attenuating lung cancer progression.

Abstract 4792: Analysis of the relationship between experimentally induced rodent forestomach hyperplasia and tumorigenesis

Hyperplasia is an increase in cell number resulting from physiological processes such as irritation, or pathological processes like carcinogenesis. The difficulty in differentiating reactive versus preneoplastic (or dedicated) hyperplasia has been the subject of debate in the literature, especially in regard to prediction of human health risks following chronic chemical exposure. Squamous hyperplasia and neoplasia are frequently detected in the rodent forestomach (FS) following chronic oral administration of chemicals evaluated in rodent cancer bioassays. Molecular level mechanistic details related to FS hyperplasia progression are not available for a wide range of chemicals, despite the increasing need for this level of mechanistic understanding to support evaluations for human health risk. In order to facilitate further discussion on the use of rodent FS lesions in the estimation of cancer and noncancer reference values, a comparison of chemical hyperplasia versus tumor induction was performed. FS lesion classification and incidence data were obtained from rat and mouse gavage bioassays on over 50 chemicals from National Toxicology Program (NTP) 2-year bioassays that reported dose-related increases in FS hyperplastic or neoplastic lesions in one or more rodent sex/strain combinations tested. Chemical effects were tabulated and sorted by strain, sex, genotoxicity assay results and irritation effects, and the relationship between FS hyperplasia and FS tumor (e.g., squamous cell papilloma or carcinoma) induction was analyzed using grouped animal data. When considering chemicals with positive results in genotoxicity assays, FS tumors positively correlated with FS hyperplasia incidence in both rats and mice. Increased incidence of FS hyperplasia was not correlated with FS tumors in animals exposed to chemicals that were negative for genotoxicity and irritation. The potential results of this analysis may be useful in the evaluation of chemicals with limited chronic bioassay data by informing predictions of long-term tumor formation based on chemical properties observable during short-term animal or in vitro studies (e.g., genotoxicity, irritation).

The views expressed in this abstract are those of the authors and do not necessarily represent the views or policies of the U.S. Environmental Protection Agency.

Citation Format: Jason M. Fritz, Maureen R. Gwinn. Analysis of the relationship between experimentally induced rodent forestomach hyperplasia and tumorigenesis. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4792. doi:10.1158/1538-7445.AM2013-4792

Stimulation of neoplastic mouse lung cell proliferation by alveolar macrophage-derived, insulin-like growth factor-1 can be blocked by inhibiting MEK and PI3K activation

Background

Worldwide, lung cancer kills more people than breast, colon and prostate cancer combined. Alterations in macrophage number and function during lung tumorigenesis suggest that these immune effector cells stimulate lung cancer growth. Evidence from cancer models in other tissues suggests that cancer cells actively recruit growth factor-producing macrophages through a reciprocal signaling pathway. While the levels of lung macrophages increase during tumor progression in mouse models of lung cancer, and high pulmonary macrophage content correlates with a poor prognosis in human non-small cell lung cancer, the specific role of alveolar macrophages in lung tumorigenesis is not clear.

Methods

After culturing either an immortalized lung macrophage cell line or primary murine alveolar macrophages from naïve and lung-tumor bearing mice with primary tumor isolates and immortalized cell lines, the effects on epithelial proliferation and cellular kinase activation were determined. Insulin-like growth factor-1 (IGF-1) was quantified by ELISA, and macrophage conditioned media IGF-1 levels manipulated by IL-4 treatment, immuno-depletion and siRNA transfection.

Results

Primary macrophages from both naïve and lung-tumor bearing mice stimulated epithelial cell proliferation. The lungs of tumor-bearing mice contained 3.5-times more IGF-1 than naïve littermates, and media conditioned by freshly isolated tumor-educated macrophages contained more IGF-1 than media conditioned by naïve macrophages; IL-4 stimulated IGF-1 production by both macrophage subsets. The ability of macrophage conditioned media to stimulate neoplastic proliferation correlated with media IGF-1 levels, and recombinant IGF-1 alone was sufficient to induce epithelial proliferation in all cell lines evaluated. Macrophage-conditioned media and IGF-1 stimulated lung tumor cell growth in an additive manner, while EGF had no effect. Macrophage-derived factors increased p-Erk1/2, p-Akt and cyclin D1 levels in neoplastic cells, and the combined inhibition of both MEK and PI3K ablated macrophage-mediated increases in epithelial growth.

Conclusions

Macrophages produce IGF-1 which directly stimulates neoplastic proliferation through Erk and Akt activation. This observation suggests that combining macrophage ablation therapy with IGF-1R, MEK and/or PI3K inhibition could improve therapeutic response in human lung cancer. Exploring macrophage-based intervention could be a fruitful avenue for future research.

Regulation of cytokine-induced prostanoid and nitric oxide synthesis by extracellular signal&#x2013;regulated kinase 1/2 in lung epithelial cells

The inflammatory cytokines tumor necrosis factor alpha (TNFα) and interferon gamma (IFNγ) stimulate production of the inflammatory mediators prostaglandin E₂ (PGEγ), prostacyclin (PGIγ), and nitric oxide (NO) in cultured lung epithelial cells. Pretreatment of these cells with the selective MEK1/2 (mitogen-activated protein kinase/extracellular signal-regulated kinase [ERK] kinase 1/2) inhibitor U0126 blocked ERK1/2 activation and inhibited cytokine-induced production of these inflammatory mediators. Primary bronchiolar epithelial Clara cells treated with TNFα and IFNγ also produced increased PGE₂, PGI₂, and NO, and PG and NO production was decreased by MEK inhibition. U0126 differentially affected cyclooxygenase (COX)-1, COX-2, and inducible NO synthase (iNOS) expression in cell lines, however, suggesting that MEK1/2 regulates prostanoid and NO production by means other than inducing their biosynthetic enzymes. Functionally, inhibition of MEK1/2 caused G1 cell cycle arrest and decreased cyclin D1 expression, but these effects were not related to decreased prostanoid production. These results indicate separate proinflammatory and proliferative roles for ERK1/2 in lung epithelial cells. During lung tumor formation in vivo, ERK1/2 phosphorylation increased as lung tumors progressed. Since tumor-derived cells were more sensitive than nontumorigenic cells to the antiproliferative effects of U0126, MEK1/2 inhibition may serve as an attractive chemotherapeutic target.

Inhibition by erlotinib of primary lung adenocarcinoma at an early stage in male mice

PURPOSE

Erlotinib, a small molecule inhibitor of the tyrosine kinase (TK) domain of epidermal growth factor receptor (EGFR), increases survival of advanced non-small cell lung cancer patients who failed standard chemotherapy (Phase III study). We evaluated whether erlotinib is also effective at an early stage of primary lung tumorigenesis in a carcinogen-induced lung tumor model in mice.

METHODS

Sixteen weeks after carcinogen (urethane) injection, when small self-contained adenomas are evident, male and female A/J mice were treated IP with 10 mg/kg erlotinib or Captisol vehicle daily over 3.5 weeks (15 mice per group). The efficacy, metabolism and mechanism of action of erlotinib were evaluated.

RESULTS

Erlotinib reduced tumor burden in males by twofold compared to vehicle (12.7 +/- 1.2 vs 26.2 +/- 2.5 mg, respectively; p < 0.0001), while tumor burden in erlotinib-treated females slightly increased compared to vehicle by 21% (15.1 +/- 1.2 vs 11.9 +/- 0.9 mg, respectively; p < 0.05). Tumor multiplicity, in contrast, was unaffected by erlotinib. The levels of erlotinib that accumulated in plasma, lung tumor tissue and adjacent uninvolved (UI) lung were comparable in males and females. Males, however, accumulated more OSI-420, an active and pharmacologically equipotent metabolite of erlotinib, than females in plasma, lung tumors, and UI lung. In both genders, 80% of tumors contained Kras mutations at codon 61, but no EGFR mutations were detected. The cellular distribution and concentration of EGFR were also similar between genders. In control mice, however, phosphorylated EGFR (pEGFR) levels were nearly 2.5-fold higher in males compared to females in UI lungs and sevenfold higher in lung tumors. Further, erlotinib decreased the contents of pEGFR in UI lungs and lung tumors, particularly in males.

CONCLUSIONS

Adenomas from male mice in this early lung cancer model are responsive to erlotinib treatment, possibly because of a greater dependence of male tumor growth on the EGFR pathway compared to females. Importantly, these results indicate that small lung adenomas from male mice that utilize EGFR signaling but also harbor Kras mutations shrink in response to erlotinib, suggesting that erlotinib may be beneficial for some patients very early during lung cancer progression.

A comparison of fear-avoidance beliefs in patients with lumbar spine pain and cervical spine pain

STUDY DESIGN

A prospective consecutive cohort study of patients with cervical spine pain and patients with lumbar spine pain referred to an academic medical center.

OBJECTIVES

To investigate the presence of fear-avoidance beliefs in a sample of patients with cervical spine pain and to compare the association of pain intensity, disability, and fear-avoidance beliefs in patients with cervical spine pain with that in patients with lumbar spine pain.

SUMMARY OF BACKGROUND DATA

Fear-avoidance beliefs are a specific psychosocial variable involved in the development of disability from low back pain. Psychosocial variables are believed to play a role in cervical disability, but specific variables have not been investigated.

METHODS

Consecutive patients referred to a multidisciplinary center completed self-reports of disability, pain intensity, and fear-avoidance beliefs during an initial evaluation session. Gender, type of symptom onset, acuity, and payer source were also recorded. Associations between disability, pain intensity, and fear-avoidance beliefs were investigated in patients with cervical spine pain and patients with lumbar spine pain.

RESULTS

In all, 163 patients completed the self-reports and were included in this study. Weaker relations between fear-avoidance beliefs and disability were found in patients with cervical pain than in those with lumbar pain. Significant differences in fear-avoidance beliefs were found for gender, type of symptom onset, and payer source (workers' compensation, auto insurance, and traditional insurance).

CONCLUSION

The associations among fear-avoidance beliefs, pain intensity, and disability differed between patients with cervical spine pain and patients with lumbar spine pain. Fear-avoidance beliefs were significantly different in subgroups of patients.

Examining diagnostic tests: an evidence-based perspective

Diagnosis is an important aspect of physical therapist practice. Selecting tests that will provide the most accurate information and evaluating the results appropriately are important clinical skills. Most of the discussion in physical therapy to date has centered on defining diagnosis, with considerably less attention paid to elucidating the diagnostic process. Determining the best diagnostic tests for use in clinical situations requires an ability to appraise evidence in the literature that describes the accuracy and interpretation of the results of testing. Important issues for judging studies of diagnostic tests are not widely disseminated or adhered to in the literature. Lack of awareness of these issues may lead to misinterpretation of the results. The application of evidence to clinical practice also requires an understanding of evidence and its use in decision making. The purpose of this article is to present an evidence-based perspective on the diagnostic process in physical therapy. Issues relevant to the appraisal of evidence regarding diagnostic tests and integration of the evidence into patient management are presented.

A comparison of a modified Oswestry Low Back Pain Disability Questionnaire and the Quebec Back Pain Disability Scale

BACKGROUND AND PURPOSE

The quality of a disability scale should dictate when it is used. The purposes of this study were to examine the validity of a global rating of change as a reflection of meaningful change in patient status and to compare the measurement properties of a modified Oswestry Low Back Pain Disability Questionnaire (OSW) and the Quebec Back Pain Disability Scale (QUE).

SUBJECTS

Sixty-seven patients with acute, work-related low back pain referred for physical therapy participated in the study.

METHODS

The 2 scales were administered initially and after 4 weeks of physical therapy. The Physical Impairment Index, a measure of physical impairment due to low back pain, was measured initially and after 2 and 4 weeks. A global rating of change survey instrument was completed by each subject after 4 weeks.

RESULTS

An interaction existed between patients defined as improved or stable based on the global rating using a 2-way analysis of variance for repeated measures on the impairment index. The modified OSW showed higher levels of test-retest reliability and responsiveness compared with the QUE. The minimum clinically important difference, defined as the amount of change that best distinguishes between patients who have improved and those remaining stable, was approximately 6 points for the modified OSW and approximately 15 points for the QUE.

CONCLUSION AND DISCUSSION

The construct validity of the global rating of change was supported by the stability of the Physical Impairment Index across the study period in patients defined as stable by the global rating and by the decrease in physical impairment across the study period in patients defined as improved by the global rating. The modified OSW demonstrated superior measurement properties compared with the QUE.

The use of nonorganic signs and symptoms as a screening tool for return-to-work in patients with acute low back pain

STUDY DESIGN

A longitudinal cohort study of patients with acute, work-related low back pain undergoing physical therapy treatment.

OBJECTIVE

To determine cut-off values maximizing the predictive ability of the nonorganic signs and symptoms in patients with acute, work-related low back pain and to calculate the predictive validity of the signs and symptoms, alone and in combination, using an outcome of return to work within 4 weeks of initiating treatment.

SUMMARY OF BACKGROUND DATA

Waddell et al have proposed nonorganic signs and symptoms as screening tools in patients with chronic low back pain for detecting the presence of abnormal illness behavior and identifying patients in need of further evaluation to improve the likelihood of a successful treatment outcome.

METHODS

Consecutive patients referred to physical therapy with work-related low back pain of less than 2 weeks' duration were examined for the presence of nonorganic signs and symptoms before initiating physical therapy treatment. The outcome measure used was the ability to return to work without restrictions within 4 weeks of the initial evaluation.

RESULTS

Sensitivity, specificity, and likelihood ratios were calculated for all possible cut-off values for the nonorganic signs, symptoms, and the nonorganic index (signs and symptoms). The best cut-off values were two or more signs (negative likelihood ratio = 0.75), three or more symptoms (negative likelihood ratio = 0.62), and an index score of three or more (negative likelihood ratio = 0.59). Area under a receiver operator characteristic curve for the signs, symptoms, and index were 0.60, 0.63, and 0.63, respectively.

CONCLUSIONS

Because the nonorganic tests are purported to serve as screening tests, cut-off values were selected that minimized false-negative results. Even with optimal cut-off values, none of the nonorganic tests served as effective screening tools. Other screening tools may prove more effective for the early identification of patients at increased risk for delay in returning to work after an episode of acute low back pain.

Interrater reliability of judgments of the centralization phenomenon and status change during movement testing in patients with low back pain

OBJECTIVE

To determine the interrater reliability of judgments of status change, including the centralization phenomenon during examination of the lumbar spine, and to determine the effects of training and experience on reliability.

DESIGN

A videotape study of judgments by physical therapists and physical therapy students of the results of movement testing during the examination of patients with low back pain.

SETTING

Outpatient physical therapy clinic.

PATIENTS

Patients receiving physical therapy treatment for low back pain.

INTERVENTION

Patients with low back pain were videotaped while performing a variety of movement tests including single, repeated, and sustained movements. Forty licensed physical therapists and 40 physical therapy students were provided with operational definitions of the three potential judgments of status change with movement testing; centralization, peripheralization, status quo. All therapists and students viewed the videotape and made a judgment regarding the patient's status change in response to the test.

MAIN OUTCOME MEASURE

Percentage agreement and kappa coefficient values for agreement.

RESULTS

Interrater reliability was excellent for the total sample of examiners (kappa = .793), for the licensed physical therapists (kappa = .823), and for the students (kappa = .763).

CONCLUSIONS

Judgments of status change are reliable when operational definitions are provided. Clinical experience does not appear to substantially improve reliability.

The use of a classification approach to identify subgroups of patients with acute low back pain. Interrater reliability and short-term treatment outcomes

STUDY DESIGN

A prospective, consecutive, cohort study of patients with acute low back pain classified into subgroups based on examination data and treated with a specific treatment approach.

OBJECTIVE

To calculated the interrater reliability of a classification system, and to compare initial patient characteristics and outcomes of physical therapy treatment when a classification approach is used.

SUMMARY OF BACKGROUND DATA

Classification of patients with low back pain into homogeneous subgroups has been identified as a research priority. Identifying relevant subgroups of patients could improve clinical outcomes and research efficiency.

METHODS

Consecutive patients referred to physical therapy for treatment of acute low back pain were evaluated and classified into one of four subgroups (immobilization, mobilization, specific exercise, or traction) before treatment. Physical therapy treatment was based on the patient's classification. The classifications were compared for initial patient characteristics, frequency and duration of physical therapy, and improvement in Oswestry scores.

RESULTS

In this study, 120 patients were evaluated and classified. Analysis of interrater reliability showed a kappa value of 0.56. Differences were found among the classifications for age, initial Oswestry score, history of low back pain, symptom distribution, and average change in Oswestry score with treatment.

CONCLUSIONS

Reaching a consensus regarding relevant patient subgroups requires data on the reliability and validity of existing classification systems. Further work is required to validate improvement in treatment outcomes using a classification approach.

An examination of the selective tissue tension scheme, with evidence for the concept of a capsular pattern of the knee

BACKGROUND AND PURPOSE

The purpose of this study was to examine whether there is evidence to support 2 elements of the passive-range-of-motion (PROM) portion of Cyriax's selective tissue tension scheme for patients with knee dysfunction: a capsular pattern of motion restriction and the pain-resistance sequence.

SUBJECTS

One hundred fifty-two subjects with unilateral knee dysfunction participated. The subjects had a mean age of 40.0 years (SD=15.9, range=13-82).

METHODS

Passive range of motion of the knee and the relationship between the onset of pain and resistance to PROM (pain-resistance sequence) were measured, and 4 tests for inflammation were used. Interrater reliability was assessed on 35 subjects.

RESULTS

Kappa values for the individual inflammatory tests ranged from .21 to .66 for categorization of the joint as inflamed, based on at least 2 positive inflammatory tests (kappa=.76). Reliability of PROM measurements was indicated by intraclass correlation coefficients of .72 to .97. Reliability of measurements of the pain-resistance sequence was indicated by a weighted kappa of .28. A capsular pattern, defined as a ratio of loss of extension to loss of flexion during PROM of between 0.03 and 0.50, was more likely than a noncapsular pattern in patients with an inflamed knee or osteoarthrosis (likelihood ratio=3.2). An association was found between a capsular pattern and arthrosis or arthritis.

CONCLUSION AND DISCUSSION

These findings provide evidence to support the concept of a capsular pattern of motion restriction in persons with inflamed knees or evidence of osteoarthrosis.

Use of a classification approach to the treatment of 3 patients with low back syndrome

The purpose of this report is to present the use of a classification system based on signs and symptoms to guide treatment in 3 patients with low back syndrome. Each patient had signs and symptoms of compressive nerve root pathology with a similar anatomical distribution of pain. Each patient was treated with a different approach based on the assigned classification. One patient was classified as needing treatment for a lateral shift, one patient was classified as needing flexion-oriented treatment, and the other patient was classified as needing extension-oriented treatment. The approach used for each patient was successful in reducing patient-reported pain severity and level of functional disability (Modified Oswestry Low Back Pain Questionnaire score). The potential advantages of the use of signs and symptoms to guide treatment classifications and decisions versus decisions based on suspected pathology or symptom distribution are discussed.

Lumbar spinal stenosis: a review of current concepts in evaluation, management, and outcome measurements

The purpose of this review is to present current information from the literature regarding the pathoanatomy, clinical presentation, differential diagnosis, treatment, and outcome assessment methods for patients with lumbar spinal stenosis. Lumbar spinal stenosis is a frequently encountered condition, particularly in the elderly. Treatment requires an accurate diagnosis, but differential diagnosis of lumbar stenosis can be difficult. The literature to date has focused primarily on surgical treatment. The long-term efficacy of surgery has been questioned, and surgical procedures are associated with increased costs and risks of morbidity in an elderly population. A trial of conservative care is recommended in most cases, but there are presently no randomized controlled studies in the literature comparing surgical versus conservative management, or evaluating the effectiveness of any specific conservative treatment approach. The existing literature has further been criticized for having poorly defined outcome measures. The assessment of treatment outcomes should be multifactorial, including measures of pathoanatomy and impairments, as well as patient-centered measures such as level of disability, patient expectations, and satisfaction. The present level of understanding of lumbar spinal stenosis is deficient in many areas, including differential diagnosis, treatment, and outcome assessment. Future research should address these deficits to improve the management of patients with this condition.

Preliminary results of the use of a two-stage treadmill test as a clinical diagnostic tool in the differential diagnosis of lumbar spinal stenosis

This study assesses the ability of a two-stage treadmill test to distinguish stenotic from nonstenotic subjects by capitalizing on the postural dependency of stenotic symptoms. Forty-five subjects (26 stenotic, 19 nonstenotic) participated. An earlier onset of symptoms with level walking (p = 0.0009), increased total walking time on an inclined treadmill (p = 0.014), and prolonged recovery time after level walking (p = 0.001) were significantly associated with stenosis. Only one of four self-reported postural variables were significantly associated with stenosis. Linear discriminant analysis performed using the treadmill variables resulted in the correct classification of 76.9 and 94.7% of stenotic and nonstenotic subjects, respectively. Likelihood ratios for all treadmill variables were > 2.50, and < 2.00 for all self-report variables. A two-stage treadmill test may be useful in the differential diagnosis of lumbar stenosis, and clinical measurement of the postural nature of symptoms seems to be superior to subjects' self-reports.

A nonsurgical treatment approach for patients with lumbar spinal stenosis

The purpose of this case report is to describe a physical therapy approach to the evaluation, treatment, and outcome assessment of two patients diagnosed with lumbar spinal stenosis. Evaluation consisted of assessment of neurological status, spinal range of motion, and lower-extremity muscle force production and flexibility; administration of the Modified Oswestry Low Back Pain Questionnaire and the Roland-Morris Disability Questionnaire; assessment of pain using a visual analog scale; and performance of a two-stage treadmill test. The treatment program was designed to treat the impairments, and harness-supported treadmill ambulation (unloading) was used to address the limitation in ambulation identified by the treadmill test. Outcome assessment included measuring changes in the status of the impairments and assessing responses to the disability questionnaires and performance of the two-stage treadmill test. Improvements were noted on all outcome measures for both patients after 6 weeks of physical therapy and at the 4-week follow-up examination. Larger case series and randomized trials with long-term follow-ups are recommended.

Rehabilitation following allograft meniscal transplantation: a review of the literature and case study

Treatment of meniscal injuries in the knee has evolved over the past three decades. New research regarding the functional roles of the menisci has increased emphasis on the preservation of meniscal tissue. Meniscal transplantation has developed as a surgical technique for individuals whose menisci have been compromised through trauma or previous meniscectomy. The purpose of this article is to review the current literature regarding meniscal function, the deleterious effects of meniscectomy, and the development of transplantation of allograft menisci as a surgical technique. A case study of a 28-year-old male undergoing medial meniscus transplantation is presented, with emphasis on the development of postoperative rehabilitation guidelines.

Immunochemical detection of the multidrug resistance-associated protein MRP in human multidrug-resistant tumor cells by monoclonal antibodies

We have generated rat and murine monoclonal antibodies against multidrug resistance-associated protein (MRP), a M(r) 180,000-195,000 membrane glycoprotein involved in a non-P-glycoprotein multidrug resistance of human tumor cells. The antibodies were raised against two different segments of MRP and found to be suitable for protein blot analyses, immunohistochemical and cytochemical studies, as well as flow cytometry of permeabilized cells. The antibodies do not cross-react with the human P-glycoproteins. Immunocytochemistry using MRP-overexpressing tumor cells of different histogenetic origins showed that MRP is predominantly located in the plasma membrane. Immunoelectron microscopy confirmed the plasma membrane location of MRP. The MRP antibodies provide a sensitive and specific tool for studies on MRP-mediated multidrug resistance.

Preventing cigarette sales to minors: the need for contextual, sociocultural analysis

BACKGROUND. Interventions designed to stop retailers from selling cigarettes to minors have been based on the untested and implicit hypothesis that the sole purpose of these sales is to maximize profits. Interventions have proceeded in the absence of clear empirical evidence that this profit motive alone actually predicts sales; there is no theoretical model regarding when, where, how, and why some retailers decide to sell cigarettes to minors while others do not. We present the first theoretical model of the retailer's decision to sell cigarettes to minors and argue that a variety of contextual and sociocultural variables enter into that decision. We discuss the manner in which this model might be used to improve the effectiveness of future preventive interventions with retailers.

The problem and sociocultural context of single-cigarette sales

OBJECTIVE

To provide data on the sale of single cigarettes to adults and minors and to examine the sociocultural context in which these sales occur.

DESIGN

A naturalistic observation study using repeated measures. Two hundred six stores in a convenience sample were visited by one minor and one adult who each attempted to purchase a single cigarette.

MAIN OUTCOME MEASURES

Single-cigarette sales to an adult and/or minor. Data were obtained on type of store and, if a sale occurred, on the price, brand, and packaging of the cigarette. The ethnic composition of the neighborhood surrounding each store was determined.

RESULTS

One hundred one (49.1%) of the stores sold single cigarettes. Singles were sold significantly more often to minors than to adults, and when both could make a purchase, minors paid more for these singles than did adults. Singles were least likely to be sold in white neighborhoods, more likely to be sold in integrated neighborhoods, and most likely to be sold in minority neighborhoods. Minors were able to purchase single cigarettes during 34.4% of the visits to white neighborhoods but could do so during 71.2% of the visits to minority neighborhoods; adults were able to make similar purchases during 24% of the visits to white neighborhoods and 37.3% of the visits to minority neighborhoods.

CONCLUSIONS

The illegal sale of single cigarettes involves complex sociocultural factors heretofore unexamined. An understanding of such factors may be useful in planning merchant education programs and drafting policy to control illegal sales.

Evidence for a role of the monoclonal antibody E48 defined antigen in cell-cell adhesion in squamous epithelia and head and neck squamous cell carcinoma

Monoclonal antibody (MAb) E48 recognizes a 20- to 22-kDa antigen expressed by human squamous and transitional epithelia and their neoplastic counterparts. Histochemical examination of these tissues revealed distinct surface labeling with MAb E48. To investigate the subcellular localization of the E48 antigen we have performed electron microscopical analysis. In cells of normal oral mucosa, the E48 antigen was expressed on the plasmalemma, particularly associated with desmosomes, suggesting involvement of the E48 antigen in intercellular adhesion. Furthermore, the level of expression of the E48 antigen appeared to be influenced by the cellular organization. In squamous cell carcinoma (SCC) cell lines grown in vitro as subconfluent monolayer cultures, the E48 antigen expression was low. However, E48 antigen expression increased when SCC cells were grown to confluency. E48 antigen expression was similarly high when SCC cell lines were cultured under conditions promoting three-dimensional growth either as colonies within floating collagen gels or as xenograft in tumor-bearing nude mice. Further evidence for the involvement of the E48 antigen in cell-cell adhesion was found when SCC cells were grown within collagen gels in the presence of MAb E48: no spherical colonies were formed, but cells grew out to colonies composed of single cells. Moreover, in this culture system the percentage of SCC cells growing out to colonies was decreased by the presence of MAb E48. These findings indicate that the E48 antigen is involved in the structural organization of squamous tissue and might have a role in intercellular adhesion.

Acute dissection of the ascending aorta. Initial presentation as acute lower GI bleeding

We present the unusual case of a 56-year-old man with acute dissection of the ascending aorta (DeBakey type I) whose presenting symptoms were those of lower gastrointestinal (GI) bleeding. Surgical repair was successfully accomplished with resection of the aorta with a Dacron tubular graft combined with aortic valvular replacement after obtaining bowel viability.

Fontan operation: modification of the valve position in conduit with brief review of the literature

A Fontan operation was performed on a 10-year-old child for correction of tricuspid atresia. A xenograft, valved conduit was used to establish continuity between the right atrium and the small right ventricle. Atrial and ventricular septal defects were repaired with Dacron patches. Two hours postoperatively, the patient suffered a cardiac arrest secondary to hypoxia and was successfully resuscitated. Partial recurrence of a right-to-left shunt at the atrial level necessitated the patient's return to surgery. The insufficient conduit was replaced and the leaking patches were resutured. The conduit was shortened to one-third its length, and the conduit valve was repositioned directly at the proximal end, over the right atriotomy. Ten months postoperatively, the patient remains in stable condition.

Severe blood transfusion reaction from leukoagglutinin antibody with successful treatment by membrane oxygenation

In the intensive care unit immediately after a triple aortocoronary bypass procedure, a 62-year-old man presented with copious amounts of frothy secretions in the endotracheal tube, became severely hypotensive, and remained hypoxic in the presence of maximum respiratory support. Chest roentgenograms showed pronounced pulmonary edema. Prior to leaving the operating room, the patient had received 1 unit of whole blood. A leukoagglutinin reaction to this blood transfusion was determined to be the cause of the pulmonary edema. When the patient continued to deteriorate after administration of diuretics, vasopressors, corticosteroids, albumin, and maximum respiratory support, the Sci-Med membrane oxygenator was inserted by the right femoral vein-artery. Bypass was continued for approximately 8 hours, until the PaO2 increased and the patient's condition stabilized. We think this is the first reported case of membrane oxygenation for treatment of noncardiogenic pulmonary edema due to leukoagglutinin reaction. It indicates the need for early diagnosis and utilization of the membrane oxygenator when other methods of treatment fail.