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This case study examines factors affecting the use of equipment designed to prevent lower back strain in laborers who pour concrete on major highway construction sites. Qualitative methods of organizational analysis were used to characterize factors identified from interviews and participant observation. The major obstacles to the use of the control on site were1. Managers placing a low priority on ergonomics2. Safety officers' limited power in organizational hierarchies3. Rationalizing, rather than challenging, resistance to change4. Lack of a forum to share knowledge about interventionsSeveral organizational factors impeded the adoption of a technically effective, low-cost safety control on the site studied. The implementation of the control ultimately resulted from actions taken by the investigators, suggesting that safety programs present at the site are not alowys adequate to realize feasible interventions. [ABSTRACT FROM AUTHOR]

Describes the ergonomic analysis of New York apple harvest work using a posture-activities-tool-handling work sampling approach. Mean coefficients of variation; Most frequently observed activities; Weight bearing observed 78.5 percent of the time throughout a range of activities; Apple harvest work comparable with other ergonomically high-risk occupations.

The lobster-harvesting industry has a high occupational injury incidence compared to land-based industries. Participatory ergonomics methods were used to partner with lobstermen to develop and implement ergonomic improvements. The model included training in ergonomics principles, a forum for ergonomics discussions, and a sequence of meetings planned to focus on problem identification, intervention, evaluation, and dissemination of findings. One crew initiated 3 specific actions: the introduction of a conveyor belt to assist material handling at a local lobstering pier, the installation of a star block at the space for hauling traps onto the boat, and the initiation of a design process for improved mechanical assistance for hauling traps onto the boat. The other crew took action to reduce force and postural exposures by creating a short video intended to disseminate ergonomic ideas to other lobstermen. The influence of important cultural norms was observed for future research and development in the community.

The opioid epidemic has had disproportionate effects across various sectors of the population, differentially impacting various occupations. Commercial fishing has among the highest rates of occupational fatalities in the United States. This study used death certificate data from two Massachusetts fishing ports to calculate proportionate mortality ratios of fatal opioid overdose as a cause of death in commercial fishing. Statistically significant proportionate mortality ratios revealed that commercial fishermen were greater than four times more likely to die from opioid poisoning than nonfishermen living in the same fishing ports. These important quantitative findings suggest opioid overdoses, and deaths to diseases of despair in general, deserve further study in prevention, particularly among those employed in commercial fishing.

Background: Liposarcoma of the larynx is a rare entity. Well-differentiated spindle cell liposarcoma of the larynx has not been yet reported in the literature., Case Report: We report the first case of well-differentiated spindle cell liposarcoma of the larynx on a 59-year-old male who presented with change of voice and phlegmy cough for several months. Laryngoscopy revealed a mucosal covered pedunculated mass on the supraglottis. Computerized tomography (CT) scan showed a low-attenuation mass causing moderate narrowing of the airway. The lesion was excised. Grossly, a 4.2 cm ovoid, solid and soft mass with homogeneously white-gray and rubbery cut surface was identified. Microscopic examination revealed a well-demarcated neoplasm composed of predominantly atypical and pleomorphic spindle cells distributed in collagenous stroma, with admixed adipocytes showing variation in cell size and rare lipoblasts. Immunohistochemical stains showed that the spindle cells were positive for MDM2, CDK4, and CD34. Overall, the histology and immunoprofile are consistent with a well-differentiated liposarcoma, spindle cell type. Due to the positive resection margin, the patient subsequently received endoscopic local re-excision with a carbon dioxide laser. He did well at 4 months after primary excision., Conclusion: This case illustrates that while well-differentiated spindle cell liposarcoma rarely occurs in the larynx, it should be considered in the differential diagnosis of patients with laryngeal lesions. A panel of immunohistochemistry markers including MDM2, CDK4 and CD34 is helpful to render accurate diagnosis. Wide excision with long-term follow-up is necessary for this rare variant of liposarcoma., (Copyright © 2021 International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Rationale & Objective: Digital health system tools to support shared decision making and preparation for kidney replacement treatments for patients with chronic kidney disease (CKD) are needed., Study Design: Descriptive study of the implementation of digital infrastructure to support a patient-centered health system intervention., Setting & Participants: 4 CKD clinics within a large integrated health system., Exposure: We developed an integrated suite of digital engagement tools to support patients' shared decision making and preparation for kidney failure treatments. Tools included an automated CKD patient registry and risk prediction algorithm within the electronic health record (EHR) to identify and prioritize patients in need of nurse case management to facilitate shared decision making and preparation for kidney replacement treatments, an electronic patient-facing values clarification tool, a tracking application to document patients' preparation for treatments, and an EHR work flow to broadcast patients' treatment preferences to all health care providers., Outcomes: Uptake and acceptability., Analytic Approach: Mixed methods., Results: From July 1, 2017, through June 30, 2018, the CKD registry identified 1,032 patients in 4 nephrology clinics, of whom 243 (24%) were identified as high risk for progressing to kidney failure within 2 years. Kidney Transitions Specialists enrolled 117 (48%) high-risk patients by the end of year 1. The values tool was completed by 30/33 (91%) patients who attended kidney modality education. Nurse case managers used the tracking application for 100% of patients to document 287 planning steps for kidney replacement therapy. Most (87%) high-risk patients had their preferred kidney replacement modality documented and displayed in the EHR. Nurse case managers reported that the tools facilitated their identification of patients needing support and their navigation activities., Limitations: Single institution, short duration., Conclusions: Digital health system tools facilitated rapid identification of patients needing shared and informed decision making and their preparation for kidney replacement treatments., Funding: This work was supported through a Patient-Centered Outcomes Research Institute (PCORI) Project Program Award (IHS-1409-20967)., Trial Registration: ClinicalTrials.gov NCT02722382., (© 2021 The Authors.)

Objectives : The study objective was to estimate a denominator of exposure to inshore lobstering in Full-Time Equivalents (FTEs), to count incident injury data from a sample cohort of this population, to use this count to calculate rates for incident injuries, and to use official counts of fatalities to estimate a fatality rate. Methods : Captains were randomly selected from those licensed to fish in Maine and Massachusetts. Data on work exposure and injuries that occurred on the boat were collected using a survey that was administered once per season via phone or face-to-face interview with the captain. Data included self-reports of the number of weeks worked during the season, average crew size, number of trips per week, and average trip length in hours. In addition, this survey captured relevant information (body segment affected, type of injury, and whether treatment was received) on all acute injuries occurring during the season. Only data on acute injuries were collected, and defined as having newly occurred within the last 3 months. Counts of fatalities were obtained from an official surveillance database at the National Institute for Occupational Health and Safety. Results : The total occupational exposure reported for the cohort was over 2 million man-hours over 4 years, resulting in an average annual FTE of 5,847. The fatality rate averaged over 4 years was 21/100,000 FTE. The incidence rates for all injuries (51.0/100 FTE) and injuries receiving treatment (17.5/100 FTE) were much higher than those reported in other studies of fishing that used US Coast Guard data. Lobstermen presented with all categories of injuries, sprains being the most frequent (7.8/100 FTE) and amputations the least (0.2/100 FTE). Wrist/hand injuries on the right side occurred most frequently of all body locations (3.6/100 FTE). Conclusion : Non-fatal injuries occur at high rates in lobstering. The impact of interventions aimed at exposure to risk for sprains and cuts has potential to affect the most lobstermen. Fatality rate appears to have been unchanging since the year 2000.

Background: The objective of this study was to report on the prevalence of musculoskeletal pain in lobstermen in the northeast USA., Methods: Crews were randomly selected from those licensed to fish in Maine and Massachusetts and followed prospectively. The survey used a Nordic Musculoskeletal Questionnaire format to characterize musculoskeletal disorders., Results: A total of 395 individuals participated. One half of the respondents reported low back pain. Back pain was attributed to or exacerbated by lobstering. Low back pain was prevalent among both captains and sternmen, while sternmen reported more hand/wrist pain than captains. Multiple locations for pain were common in individual participants., Conclusion: Equipment or technology to assist material handling should be a priority, as the body segments with high prevalence of pain (back, hand/wrists, shoulders, knees) are all affected by the repetitive and forceful handling of the lobster traps.

The objective of this study was to inform efforts to reduce risk for musculoskeletal disorders among commercial lobstermen by characterizing and quantifying injuries that occur to people while harvesting lobsters commercially in the Northeast United States. This study aimed to estimate a denominator of exposure to lobstering in full-time equivalents (FTE), to estimate a fatality rate, and to calculate incidence rates for acute injuries within the sample population. Captains were randomly selected from those licensed to fish in Maine and Massachusetts. Data on work exposure and injuries with rapid onset that occurred on the boat ("acute injuries") were collected using a survey, which was administered quarterly via phone or face-to-face interview with the captain. The quarterly survey assessed the number of weeks worked during the quarter, average crew size, number of trips per week, and average trip length in hours. In addition, this survey captured relevant information (body segment affected, type of injury, and whether treatment was received) on all acute injuries occurring during the quarter. FTE were estimated using fishermen days and fishermen hours. The annual FTE estimated using days was 2,557 and using hours was 2,855. As expected, the summer months (3rd quarter) had the highest FTE and the winter (1st quarter) the lowest FTE. Fall (4th quarter) and spring (2nd quarter) ranked second and third, respectively. The incidence rates for all injuries (49.7/100 FTE) and injuries requiring treatment (15.0/100 FTE) were much higher than those reported in other studies of fishing that used Coast Guard data.

Purpose: Characterize barriers and facilitators to use treadmill workstations in real work sites., Design: For 6 months, workers tried a sit-stand-walk treadmill workstation at will with expert ergonomic support. Qualitative data were collected monthly., Setting: Administrative and academic departments at a higher education institution in Massachusetts, United States., Participants: Five female administrative office workers., Method: One monthly group interview and one personal interview per participant during 6 months. Emerging topics from previous interviews were used in successive data gatherings. Transcribed data were manually coded according to the predefined topics of usability, comfort, safety, and productivity., Results: The setup of the work station, communication difficulties while walking (disrespectful, noisy), and peer pressure to maximize use were the main usability barriers. There was no event of falls. Trips were minimized. About comfort, subjects reported it hard to get used to prolonged standing position during the first month. Treadmill speed affected productivity mostly while drawing and working in spreadsheets. Lack of job autonomy was revealed as a generic barrier., Conclusion: In this female group, treadmill workstations had serious design problems for workers with not enough control of their jobs. The early identification and removal of barriers likely needs to be considered when offering these workstations to workers with low job autonomy.

Objectives/hypothesis: To compare prehematopoietic stem cell transplantation (SCT) sinus computed tomography (CT) scans to post-SCT sinus CT scans and to evaluate the relationship between pre-SCT sinus CT scans and the incidence of otolaryngology consultation after SCT., Study Design: Retrospective chart review., Methods: Charts of 228 adult SCT patients from January 2003 to June 2009 with pre-SCT sinus CT scans were reviewed. Data gathered included diagnosis, type of SCT, otolaryngology referral requests, and rhinosinusitis management. Pre- and post-SCT sinus CT scans were scored using the staging system introduced by Lund and Mackay., Results: Two hundred thirty-nine SCTs were performed on the 228 patients included in this study. No disease was identified on 25.1% of pre-SCT CT scans, mild sinus inflammation was identified on 60.7% of scans, 11.3% had moderate inflammation, and 2.9% had severe inflammation. Pre-SCT scans were found to be predictive of post-SCT CT scans. A significant proportion of patients demonstrated worsening of their Lund-Mackay score post-SCT. Pre-SCT CT scores had no predictive ability for otolaryngology consultations., Conclusions: Pre-SCT CT scan scores are associated with post-SCT scan scores; disease severity on CT may worsen following SCT and may be useful for stratifying patients into surgical versus non-surgical candidates. Further study is needed to outline the benefit of sinus surgery in these patients., (Copyright © 2012 The American Laryngological, Rhinological, and Otological Society, Inc.)

We evaluated the effect of a nursing home safe resident handling intervention on the ergonomic exposures of nursing assistants. The healthcare version of the Postures, Activities, Tools and Handling (PATH) method was used by 12 observers to examine postures, manual handling, and resident handling pre-intervention and at three months, 12 months, 24 months, and 36 months post-intervention. There were marked downward trends in proportion of work time spent repositioning and transferring residents, and an increased use of handling equipment in transferring (Cochran-Armitage tests: all p -values <0.001). While resident handling, nursing assistants were also more likely post-intervention to be in neutral trunk postures, walking rather than standing still, working with both arms below 60°, and less likely to lift loads greater than 22.7 kg. Lateral transfer devices were infrequently observed in use for repositioning; additional training on the use of this equipment is recommended to increase the benefits from the intervention program., Relevance to Industry: The study describes reductions in postural and manual handling loads of nursing assistants in nursing homes resulting from increased use of resident handling equipment following equipment installation with training and administrative support.

Objective: The study was conducted to assess the physical/ergonomic exposures that may lead to musculoskeletal injuries of Pile Drivers., Participants: Pile Drivers in the Greater Boston area., Methods: A hierarchical taxonomy for pile driving work was developed with tasks and activities defined within each of seven main pile driving operations. Exposures were characterized for the pile driving work with the PATH (Posture, Activity, Tools, and Handling) method. Data on working posture were collected for three main body parts: legs, arm and trunk., Results: A total of 8,301 observations were made on 29 Pile Drivers, on a total of 6 work sites. The lagging operation had the highest percentage of observations with non-neutral trunk (46.8%), and leg (41.0%) postures, as well as one of the lowest percentages for working on stable ground (9.0%) as observed during the lagging operation. The bracing operation had the lowest percentage for working on stable ground (0.3%). The slurry wall operation also had a low percentage of work on stable ground (6.0%). Compared to the awkward trunk and leg postures, the arm postures were less frequently observed as being awkward or non-neutral., Conclusion: The results indicate of significant exposures that could lead to musculoskeletal injuries of the back and legs for the Pile Drivers. The unstable ground conditions seemed to be one of the main concerns for this job.

This report provides an overview of physical ergonomic exposures in highway construction work across trades and major operations. For each operation, the observational method "PATH" (Posture, Activity, Tools and Handling) was used to estimate the percentage of time that workers spent in specific tasks and with exposure to awkward postures and load handling. The observations were carried out on 73 different days, typically for about 4 h per day, covering 120 construction workers in 5 different trades: laborers, carpenters, ironworkers, plasterers, and tilers. Non-neutral trunk postures (forward or sideways flexion or twisting) were frequently observed, representing over 40% of observations for all trades except laborers (28%). Kneeling and squatting were common in all operations, especially tiling and underground utility relocation work. Handling loads was frequent, especially for plasterers and tilers, with a range of load weights but most often under 15 pounds. The results of this study provide quantitative evidence that workers in highway tunnel construction operations are exposed to ergonomic factors known to present significant health hazards. Numerous opportunities exist for the development and implementation of ergonomic interventions to protect the health and safety of construction workers., (Copyright © 2010 Elsevier Ltd and The Ergonomics Society. All rights reserved.)

Purpose: Velo-cardio-facial syndrome (VCFS), the most common genetic syndrome causing cleft palate, is associated with internal carotid and vertebral artery anomalies, as well as upper airway asymmetry. Medially displaced internal carotid arteries, often immediately submucosal, present a risk of vascular injury during pharyngeal flap surgery for velopharyngeal insufficiency (VPI). We evaluate the frequency and spectrum of cervical vascular anomalies in a large cohort of VCFS patients correlating MRA with nasopharyngolaryngoscopy in detecting at risk carotid arteries. Furthermore, we assess the relationship with respect to laterality between cervical vascular patterns and the asymmetric abnormalities of these subjects' upper airways., Methods: Cervical MRAs of 86 subjects with VCFS and 50 control subjects were independently reviewed by three neuroradiologists. The course of the internal carotid and vertebral arteries was identified within the pharyngeal soft tissues. Medial deviation, level of bifurcation, dominance, anomalous origin, and vessel tortuosity were recorded. Nasopharyngoscopy examinations were available for retrospective review in 43 patients and were assessed for palatal and posterior pharyngeal wall symmetry, true vocal cord motion and size, and for the presence or absence of carotid pulsations. The endoscopic findings were compared with MRA results., Results: Of the 86 subjects, 80 (93%) had one or more vascular anomalies. 42 subjects (49%) were found to have medial deviation of at least one internal carotid artery. In 24 subjects (28%) the anomalous internal carotid artery was directly submucosal; four of these were bilateral (5% of the total sample, 17% of those with a submucosal internal carotid). Other carotid anomalies included low carotid bifurcation (44 subjects or 51%), anomalous origin of the right common carotid (32 cases, or 37%), and two cases of internal carotid agenesis/hypoplasia. Vertebral artery anomalies included vessel tortuosity (34 cases, or 40%), hypoplasia (10 cases, or 12%), looping (4 cases, or 5%), and one case of a double left vertebral artery. Though patients in our study showed an asymmetric distribution of vascular anomalies, no association was found between the laterality of palatal motion, pharyngeal fullness, or laryngeal movement and structure with ipsilateral vertebral or carotid artery anomalies. Of the 33 pulsatile carotid arteries visualized at nasopharyngoscopy, only nine were found to be submucosal on MRA. In contrast, 11 submucosal carotid arteries confirmed at MRA demonstrated no visible pulsations. Positive and negative predictive values of pulsative arteries seen endoscopically for MRA confirmation of a submucosal carotid course was 27% and 79% respectively., Conclusions: Carotid and vertebral artery anomalies are common in VCFS including marked medial deviation of the internal carotid artery in close proximity to the donor site for pharyngeal flap surgery. Lack of correlation between laterality of vascular anomalies and upper airway structural asymmetry in VCFS does not support the hypothesis that palatal, pharyngeal, and laryngeal anomalies are due to secondary developmental sequences caused by in utero vascular insufficiency. The presence or absence of carotid pulsations seen by nasopharyngoscopy does not correlate with the carotid arterial depth identified on MRA. Furthermore, identification of the relative medial-lateral retropharyngeal position of a submucosal carotid affords the opportunity to modify the surgical approach. These findings further support the routine use of pre-operative neck MRA in VCFS patients in surgical planning., (Copyright (c) 2010 Elsevier Ireland Ltd. All rights reserved.)

Abrasive blasting with silica sand has long been associated with silicosis. Alternatives to sand are being used increasingly. While NIOSH has done extensive investigations of the respiratory effects of the substitutes for sand, the ergonomic effects of the substitutes have not been examined. Too often, hazards are shifted, and technologies that might save workers' lungs could do so at the expense of their musculoskeletal systems. Hence, the objective of this study was to examine the ergonomic effects of alternatives to sand. Multiple methods, both qualitative and quantitative, were used to yield numerous kinds of data for the analysis of exposures to abrasive blasters. PATH, a method for quantifying ergonomic exposure in non-routine work, was combined with interviews with workers, biomechanical modeling and noise level readings to assess the ergonomics of two abrasive blasting operations: high-pressure water and steel shot. Advantages and disadvantages of each medium are discussed. High-pressure water was slightly less ergonomically stressful, environmentally cleaner, much quieter and less dusty that steel shot, and it was reported to be slower on those tasks where both media could be used.

The impact of modifications to the apple picking bucket on common picking postures, self-reported comfort, ease of use, and speed of harvest were measured. Fourteen apple pickers wore an intervention hip belt, were interviewed and measured using posture-activities-tools-handling methodology. The use of hip belt did not significantly alter time spent in various postures. 78.6% of interviewed workers preferred the modified bag, 71.4% noted a difference in the back, neck, or shoulder, while 64.3% said regular use of modified bag would slow their work. Major themes in worker comments are discussed. The hip belt modification to apple harvest bag seems generally acceptable to workers, but needs further development to overcome unintended effects. Although work sampling demonstrates that the bag does not affect work practices, workers appear somewhat concerned that productivity will be negatively impacted. Further training of workers in the use and potential benefits of bag are needed.

Background: Musculoskeletal disorders may not have been studied as much as greater risks in the dangerous environment of commercial fishing. Primary prevention of risk for these kinds of injuries and illnesses begins by a detailed understanding of what risks are likely to be common in the different fisheries, and how those risks might be reduced., Methods: Ergonomic job analyses were conducted on three different types of fishing vessels in Massachusetts: gillnetting, otter trawling, and lobstering. Direct observation was used to link posture to task. Noise measurements, tool analysis, and cycle time measurements were also included., Results: Production speed, materials handling, and vessel movement contributed to musculoskeletal stress by affecting observable postural deviation, repetition, and forceful exertions., Conclusions: Interventions to reduce ergonomic risk factors might be possible through utilization of below deck space in certain boats, through better technology, or through simple tool adjustments., (Copyright 2002 Wiley-Liss, Inc.)

Background: Recent research on occupational injury to apple harvest workers in New York and Pennsylvania indicates that muscle strain is one of their leading problems. A descriptive study of ergonomic risks for strains of the shoulder and lower back among apple harvesters was carried out to identify opportunities for intervention., Methods: Based upon pilot observation in four orchards, a Posture-Activities-Tools-Handling (PATH) data collection template was designed and used to analyze the work of fifty-one workers in eight additional apple orchards., Results: Physical loading on the shoulder appears to result from three major factors: reaching to pick apples with elbows over shoulder height; downward pressure from the bucket's strap in contact with the collarbone; and strain from carrying the ladder. Strain to the back appeared to come from three circumstances: static, awkward picking postures; bending to empty the picking bucket into the bin; and supporting a full load of the apples with the lower back., Conclusion: Possible intervention strategies are suggested, with emphasis on direct communication and active involvement on the part of the growers and harvesters., (Copyright 2002 Wiley-Liss, Inc.)

Community-based organizations (CBOs) have been providing HIV prevention services to priority populations for many years. Recent research suggests that CBOs could benefit from capacity building to strengthen their public health prevention knowledge and skills, including ability to access and use behavioral science to guide prevention efforts. A cross-sectional survey of 316 CBOs was conducted to assess desire and preferences for training, support for training at the organizational level, motivation for training at the individual level, barriers to training, and factors associated with the perceived need for training. Results suggest the need for a national training initiative to increase CBO capacity.

Adeno-associated virus-2 (AAV) can integrate in a site-specific manner to human chromosome 19 and is currently in phase I clinical trials for cystic fibrosis (CF) at Johns Hopkins Hospital. The goal of this study was to determine the fate of recombinant AAV containing the CFTR cDNA (AAV-CFTR) in an immortalized pseudotetraploid CF bronchial epithelial cell line (IB3-1) established from a patient with CF. Fluorescence in situ hybridization (FISH) and Southern blotting of DNA from IB3-1 cells infected with wild-type (wt) or recombinant AAV-CFTR were performed. CFRH2, an IB3-1 cell line with an estimated 15-20 integrated copies of CFTR cDNA, was used to test FISH sensitivity. All metaphase spreads had integrated copies: a single site in 36 of 56 (64.3%) and two sites within the same metaphase spread in 20 of 56 (35.7%). 3-CF-8, an IB3-1 cell line with integration of a partial CFTR cDNA (3.9 kb) was also analyzed by FISH. Integration was observed in 56 of 157 (35.7%) metaphase spreads examined. IB3-1 cells infected with wild-type AAV showed integration in 51 of 86 (59%) metaphase spreads examined. Of 51 integrations, 48 (94%) were to chromosome 19. Examination of 67 metaphase chromosome spreads of IB3-1 cells infected with AAV-CFTR vector (Azero) identified four integrations (6%) to different chromosomes. No integration was to chromosome 19 which differs significantly (P < 0.0001) from wild-type AAV. We then analyzed the A35 cell line, a clone of Azero selected for stable CFTR expression. Genomic DNA from A35 cells did not show a single site of integration; however episomal AAV-CFTR sequences were abundant in the low molecular weight DNA fraction. Examination of 68 metaphase chromosome preparations identified eight distinct integrations, none to chromosome 19. These studies show that FISH is sensitive for the detection of a partial CFTR cDNA integration. Wild-type AAV integrates in a predominantly site-specific fashion. Recombinant AAV-CFTR integrates at low frequency in a nonspecific manner and persists in episomal form in this epithelial cell line.

The cystic fibrosis transmembrane conductance regulator (CFTR) functions to regulate both Cl- and Na+ conductive pathways; however, the cellular mechanisms whereby CFTR acts as a conductance regulator are unknown. CFTR and outwardly rectifying Cl- channels (ORCCs) are distinct channels but are linked functionally via an unknown regulatory mechanism. We present results from whole-cell and single-channel patch-clamp recordings, short-circuit current recordings, and [gamma-32P]ATP release assays of normal, CF, and wild-type or mutant CFTR-transfected CF airway cultured epithelial cells wherein CFTR regulates ORCCs by triggering the transport of the potent agonist, ATP, out of the cell. Once released, ATP stimulates ORCCs through a P2U purinergic receptor-dependent signaling mechanism. Our results suggest that CFTR functions to regulate other Cl- secretory pathways in addition to itself conducting Cl-.

Bone marrow from each of 8 untreated patients with myeloproliferative disorders was grown in diffusion chambers in 760 rad total body irradiated rats. Rats were then exposed to 11.5, 57.5, or 108.5 rad daily for 14-2l d and cell growth compared to that detected in unirradiated chambers. Cells from acute myelogenous leukaemia patients exposed to 11.5 rad per d grew for 11-21 d and there was no consistent stimulation of differentiation of immature granulocytic cells to mature granulocytes that was attributable to irradiation. Cells from a chronic myeloid leukaemia patient in chronic phase or blast crisis, and a polycythaemia vera patient with myeloid metaplasia showed significant morphologic differentiation from immature to mature granulocytes in control chambers with no additional effect of daily irradiation. Marrow specimens from 2 AML patients exposed to each of 3 daily dose fractions over 14 d revealed a dose-dependent decrease in immature granulocytes with no persistent increase in mature granulocytes. In both irradiated and control chambers, macrophages increased over 21 d. Thus, cells from patients with myeloproliferative disorders may not necessarily differentiate to mature granulocytes following in vivo exposure to ionizing irradiation.