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At least 55 records · Page 3Linked to original sources
PubMed1998

Predicting return to work. A long-term follow-up study of railroad workers after low back injuries.

STUDY DESIGN: Evaluation of the long-term outcomes of 178 railroad employees with low back injury who had completed a multidisciplinary rehabilitation program. OBJECTIVES: To study two major areas: 1) outcomes of the rehabilitation program in terms of the patient's improvement in function and rate of return to work and 2) factors that predict long-term retention at work, both at the railroad and elsewhere. SUMMARY OF BACKGROUND DATA: Several studies have been published examining rehabilitation outcomes of individuals covered under workers' compensation law, but few exist that have examined railroad workers covered by the Federal Employers Liability Act, and few studies exist with follow-up periods longer than 3 years. METHODS: Physical/medical, self-reported, and employment/financial data were collected on each patient from medical and employment records. Follow-up data regarding employment status were obtained either from the employer or from the patient by telephone interview. RESULTS: On average, the patients improved in all objective and subjective measures after rehabilitation. Improvements in these measures were not predictive of return to work. At follow-up examination, 89% of the contacted patients were employed--61% still at the rail-road. The employment factors of lost work days and length of employment and the financial factor of wage rate were the most predictive of long-term work status. CONCLUSIONS: The multidisciplinary program in the current study was found to improve patient physical functioning and reduce pain. However, success in these measures was not predictive of long-term work status, suggesting that other factors have an impact on work status. Clinicians must be aware that employment and financial factors may have a strong influence on return-to-work outcomes.

Accidents, Occupational↗
PubMed2006

Chronic obstructive pulmonary disease mortality in diesel-exposed railroad workers.

Diesel exhaust is a mixture of combustion gases and ultrafine particles coated with organic compounds. There is concern whether exposure can result in or worsen obstructive airway diseases, but there is only limited information to assess this risk. U.S. railroad workers have been exposed to diesel exhaust since diesel locomotives were introduced after World War II, and by 1959, 95% of the locomotives were diesel. We conducted a case-control study of railroad worker deaths between 1981 and 1982 using U.S. Railroad Retirement Board job records and next-of-kin smoking, residential, and vitamin use histories. There were 536 cases with chronic obstructive pulmonary disease (COPD) and 1,525 controls with causes of death not related to diesel exhaust or fine particle exposure. After adjustment for age, race, smoking, U.S. Census region of death, vitamin use, and total years off work, engineers and conductors with diesel-exhaust exposure from operating trains had an increased risk of COPD mortality. The odds of COPD mortality increased with years of work in these jobs, and those who had worked >/= 16 years as an engineer or conductor after 1959 had an odds ratio of 1.61 (95% confidence interval, 1.12-2.30) . These results suggest that diesel-exhaust exposure contributed to COPD mortality in these workers. Further study is needed to assess whether this risk is observed after exposure to exhaust from later-generation diesel engines with modern emission controls.

Aged↗
PubMed1980

Herbicide exposure and tumor mortality. An updated epidemiologic investigation on Swedish railroad workers.

An earlier cohort study of Swedish railroad workers indicated a possible relationship between exposure to herbicides and an increased overall tumor morbidity and mortality. The cohort of 348 individuals has now been followed through October 1978. In this updated analysis of the causes of death among railroad workers, the observed number of tumor deaths was higher than expected, especially among individuals exposed in the earlier years of the study to both amitrol and phenoxy acids. However, the excess tumor mortality among persons exposed to amitrol became more moderate, and the earlier, slightly increased tumor mortality among people exposed to phenoxy acids more pronounced. No specific type of tumor predominated although there were three stomach cancers and three lung cancers. The result of the previous analysis of deaths among these railroad workers has been confirmed as to an excess of tumors, but the aspects of causal relationships to specific agents remain rather unclear, especially since workers exposed to a combination of amitrol and phenoxy acids seem to be the most seriously affected. However, the result, being in agreement with animal data and other epidemiologic studies, suggests a need for the careful handling of amitrol and phenoxy acids as increasingly suspicious carcinogens.

2,4,5-Trichlorophenoxyacetic Acid↗
PubMed1999

Cloning, sequence analysis, and expression of active Phrixothrix railroad-worms luciferases: relationship between bioluminescence spectra and primary structures.

Phrixothrix railroad-worms emit yellow-green light through 11 pairs of lateral lanterns along the body and red light through two cephalic lanterns. The cDNAs for the lateral lanterns luciferase of Phrixothrix vivianii, which emit green light (lambda max= 542 nm), and for the head lanterns of P. hirtus, which emit the most red-shifted bioluminescence (lambda max= 628 nm) among luminescent beetles, were cloned. Positive clones which emitted green (PvGR: lambda max= 549 nm) and red (PhRE: lambda max= 622 nm) bioluminescence were isolated. The lucifereases coded by PvGR (545 amino acid residues) and PhRE (546 amino acid residues) cDNAs share 71% identity. PvGR and PhRE luciferases showed 50-55% and 46-49% identity with firefly luciferases, respectively, and 47-49% with click-beetle luciferases. PhRE luciferase has some unique residues which replace invariant residues in other beetle luciferases. The additional residue Arg 352 in PhRE, which is deleted in PvGR polypeptide, seems to be another important structural feature associated with red light production. As in the case of other railroad-worms and click-beetle luciferases studied, Phrixothrix luciferases do not undergo the typical red shift suffered by firefly luciferases upon decreasing pH, a property which might be related to the many amino acid residues shared in common between railroad-worm and click-beetle luciferase.

Amino Acid Sequence↗
PubMedDate not supplied

Zigzags, railroads, and knots in fullerenes.

Two connections between fullerene structures and alternating knots are established. Knots may appear in two ways: from zigzags, i.e., circuits (possibly self-intersecting) of edges running alternately left and right at successive vertices, and from railroads, i.e., circuits (possibly self-intersecting) of edge-sharing hexagonal faces, such that the shared edges occur in opposite pairs. A z-knot fullerene has only a single zigzag, doubly covering all edges: in the range investigated (n </= 74) examples are found for C(34) and all C(n)() with n >/= 38, all chiral, belonging to groups C(1), C(2), C(3), D(3), or D(5). An r-knot fullerene has a railroad corresponding to the projection of a nontrivial knot: examples are found for C(52) (trefoil), C(54) (figure-of-eight or Flemish knot), and, with isolated pentagons, at C(96), C(104), C(108), C(112), C(114). Statistics on the occurrence of z-knots and of z-vectors of various kinds, z-uniform, z-transitive, and z-balanced, are presented for trivalent polyhedra, general fullerenes, and isolated-pentagon fullerenes, along with examples with self-intersecting railroads and r-knots. In a subset of z-knot fullerenes, so-called minimal knots, the unique zigzag defines a specific Kekulé structure in which double bonds lie on lines of longitude and single bonds on lines of latitude of the approximate sphere defined by the polyhedron vertices.

Journal Article↗
PubMed2002

The influence of Ala243 (Gly247), Arg215 and Thr226 (Asn230) on the bioluminescence spectra and pH-sensitivity of railroad worm, click beetle and firefly luciferases.

Among beetle luciferases, the pH-sensitive firefly luciferases have been studied extensively. Much less is known about pH-insensitive luciferases, which include click beetle and railroad worm luciferases. Previously, we found that the residues R215 and T226 (N230) are important for green light emission. Here we show that the conserved residue A243 in pH-insensitive luciferases and the corresponding G247 in pH-sensitive luciferases affect the emission spectrum and influence pH-sensitivity. In contrast to railroad worm green light-emitting (PxvGR) and firefly luciferases, the substitution of R215 in Pyrearinus termitilluminans click beetle luciferase (Pte) had no effect on the spectrum, showing that R215 is not essential for green light emission in all beetle luciferases. A homology-based model of Pte luciferase shows that R215 and T226 are close enough to interact. To investigate if there was an interaction between these conserved residues, double mutants were constructed. The double substitution R215S/T226N in Pte luciferase abolished the activity. In PxvGR luciferase the same double mutant resulted in a redshift (lambda(max) = 595 nm), whose magnitude was lower than the value expected for an additive effect. These results suggest that the effects of R215S and T226N are partially interdependent. The double substitution T226N/A243G had an additive redshift effect on the spectrum of PxvGR luciferase, whereas it had a smaller effect on the spectrum of Pte luciferase. Altogether, these results suggest that the above substitutions have different effects on the active site of click beetle and railroad worm luciferases.

Alanine↗
PubMed1985

Respiratory symptoms and pulmonary function among welders working with aluminum, stainless steel and railroad tracks.

Sixty-four aluminum welders, 46 stainless steel welders, and 149 railroad track welders were investigated regarding respiratory symptoms and pulmonary function (forced vital capacity and forced expiratory volume in 1 s). Referents consisted of nonwelding industrial workers and railroad workers. All groups of welders showed a higher frequency of chronic bronchitis symptoms than their respective referents. Respiratory symptoms were related to ozone concentrations in welders working with aluminum. In stainless steel and railroad track welders respiratory symptoms were related to chromium exposure rather than to total particle exposure. The pulmonary function was not affected in any of the welding groups studied.

Adult↗
PubMed1979

Immunofluorescence studies of dense deposit disease. The presence of railroad tracks and mesangial rings.

Immunopathologic analysis was carried out on renal tissue from patients with membranoproliferative glomerulonephritis, nine with type I and nine with type II (dense deposit disease). A specific finding in all patients with type II, but not type I, was the presence of C3 along the margin but not within the central portion of dense deposit material in the glomerular basement membrane giving a double linear appearance (railroad tracks); C3 was also present within the mesangium, outlining numerous circular structures (mesangial rings). By phase contrast, electron microscopy, and dual label fluorescence studies, the railroad tracks and mesangial rings were shown to outline dense deposit material. Mesangial rings contained properdin (four of nine patients); railroad tracks contained properdin (five of nine patients) and C4 (four of nine patients); no other complement components or immunoglobulins were present. Studies using rhodamine-conjugated rabbit antibody to human glomerular basement membrane demonstrated no reactivity with the dense deposit material itself. In type I and to a lesser extent in type II, granular deposits of C3, C4, properdin, IgM, and IgG were present along the glomerular basement membrane, suggesting that immune complexes play a role in both diseases. Dense deposit transformation of the glomerular basement membrane may be a consequence of a highly specific injury.

Autoantibodies↗
PubMed1983

Roentgenographic evidence of asbestos exposure in a select population of railroad workers.

A volunteer population of 266 current and former railroad workers was examined with posteroanterior and oblique chest roentgenograms, and a comprehensive occupational smoking history. Seventy-five percent of participants were over the age of 60, and 80% had fewer than 10 years of railroad-related asbestos exposure. Roentgenographic evidence of asbestosis was found in only six workers (2%), whereas 20% had one or more pleural changes. Radiological abnormalities were related to latency period, age, and occupation, but not to smoking habit. While selection factors qualify the results of this study, the findings support the exposure and suggest a past and future history of asbestos mortality and morbidity among steam era railway workers.

Aged↗
PubMed1990

Car driver behavior at flashing light railroad grade crossings.

The behavior of car drivers at two Dutch railroad grade crossings with automatic flashing warning lights was analyzed. Car drivers were videotaped while approaching either the red flashing lights or the white flashing "safe"-signal. Approach speeds, positions, and time intervals were semiautomatically measured from videos of more than 900 drivers: 660 while confronted with the red lights and 272 while passing the white light. Of the latter group, head movements during the approach to the crossing were also registered. Red light compliance was relatively good, as no driver was observed to cross later than 6 seconds after the onset of the red lights, despite train-arrival times of well over 60 seconds. The level of red light compliance was further quantified in terms of both the deceleration and time-to-stopping-line as accepted by drivers. From a comparison with earlier research on red light compliance at signalized road intersections it appeared that red light compliance was better at railroad crossings than at road crossings. It is concluded that faulty red light compliance is not a major cause for car-train accidents and that emphasis should be placed on the ability of the present device to attract attention and to signal unambiguously. The high degree of compliance also causes unexpected driver actions, such as emergency braking and hesitations. A yellow phase may reduce these problems. Some drivers tended to proceed immediately after a train had cleared the road instead of waiting for the end of the red signal (typically some 3 to 5 seconds after the train had passed). This tendency might reveal a major cause of dramatic errors when a second train is approaching. Immediate extinction of the red signal is suggested, or even better, a separate signal to announce the arrival of the second train. Behavior during the white signal phase also showed indications of uncertainty. In some 10% of cases drivers tended to decelerate more strongly than necessary and to make extra head movements. It is recommended that the present white flashing signal be reconsidered.

Accidents, Traffic↗
PubMed2005

Bayesian methodology incorporating expert judgment for ranking countermeasure effectiveness under uncertainty: example applied to at grade railroad crossings in Korea.

Transportation professionals are sometimes required to make difficult transportation safety investment decisions in the face of uncertainty. In particular, an engineer may be expected to choose among an array of technologies and/or countermeasures to remediate perceived safety problems when: (1) little information is known about the countermeasure effects on safety; (2) information is known but from different regions, states, or countries where a direct generalization may not be appropriate; (3) where the technologies and/or countermeasures are relatively untested, or (4) where costs prohibit the full and careful testing of each of the candidate countermeasures via before-after studies. The importance of an informed and well-considered decision based on the best possible engineering knowledge and information is imperative due to the potential impact on the numbers of human injuries and deaths that may result from these investments. This paper describes the formalization and application of a methodology to evaluate the safety benefit of countermeasures in the face of uncertainty. To illustrate the methodology, 18 countermeasures for improving safety of at grade railroad crossings (AGRXs) in the Republic of Korea are considered. Akin to "stated preference" methods in travel survey research, the methodology applies random selection and laws of large numbers to derive accident modification factor (AMF) densities from expert opinions. In a full Bayesian analysis framework, the collective opinions in the form of AMF densities (data likelihood) are combined with prior knowledge (AMF density priors) for the 18 countermeasures to obtain 'best' estimates of AMFs (AMF posterior credible intervals). The countermeasures are then compared and recommended based on the largest safety returns with minimum risk (uncertainty). To the author's knowledge the complete methodology is new and has not previously been applied or reported in the literature. The results demonstrate that the methodology is able to discern anticipated safety benefit differences across candidate countermeasures. For the 18 at grade railroad crossings considered in this analysis, it was found that the top three performing countermeasures for reducing crashes are in-vehicle warning systems, obstacle detection systems, and constant warning time systems.

Accidents, Traffic↗
PubMed2005

Suicides and other fatalities from train-person collisions on Swedish railroads: a descriptive epidemiologic analysis as a basis for systems-oriented prevention.

PROBLEM: Suicide is a dominating, although hidden, safety problem on Swedish railroads. The aim of this paper is to describe the epidemiology of fatal train-person collisions as a basis for systems-oriented prevention. METHOD: Data on collision circumstances were collected from narrative reports at the Swedish National Rail Administration. RESULTS: The events were evenly distributed by months and weekdays, however, most suicides occur during the day while unintentional events usually occur at night. Most train-person collisions happened in densely populated areas, and 75% of the suicide victims were waiting on the track before the collision. Significance test between types of injury event (suicide, accident, or unknown intent) showed small or no differences. CONCLUSION: Traditional approaches to accident prevention by systems modification seem largely applicable to combat railroad suicide as well. IMPACT ON INDUSTRY: Our findings show promising preventive potentials.

Accidents↗
PubMed1987

Lower leg replantation in children: railroad amputation.

Replantation in the lower leg, although technically feasible, still remains a complicated clinical issue in terms of the decision-making process. In children, a limb salvage or replant procedure would seem preferable; however, in crush amputations from railroad injury, a very severe trauma, difficulties in treatment should be thoroughly weighed against prosthetic possibilities: for example, only a fair or good functional outcome would justify an attempt to replant a severed shin. Unfortunately, the outcome in most cases is unpredictable at the time of initial evaluation, and even during the replantation procedure itself. To facilitate prognosis, the authors determine four typical variants of replantation course and outcome, based on local patient conditions, although they stress that no clear indications for replantation vs. prosthesis can be derived from the variants listed. Rather, general guidelines for the surgeon's decision at a very early stage of treatment are presented. Choice of procedure and tactics cannot be determined once and for all, because the prognosis for functional outcome can change during the course of treatment. Among a few well-defined situations are clean amputations (replantation is indicated) and traumas with very extensive crushing of the whole lower leg (replantation is contraindicated). In the majority of cases, replantation is a worthwhile attempt, but this does not imply that a replanted extremity must be preserved at any cost. The surgeon must consider the possibility of re-amputation, in case of an unfavorable variant in the postoperative course. A successful case of replantation, involving two lower leg railroad amputations in a child, is presented.

Adolescent↗
PubMedDate not supplied

Increased frequency of chromosomal aberrations in railroad car painters.

The purpose of this study was to determine if exposure to paints and solvents contributes to chromosomal alterations in occupationally exposed individuals. A total of 25 male railroad and underground railroad car painters were studied. This group had a mean age of 32.7 y and a mean exposure time of 5.2 y. The results were compared with those obtained for 25 healthy (unexposed) males. The scoring of structural chromosome aberrations clearly revealed an increase in the number of all types of aberrations considered in the population of painters. This suggests that exposure to a combination of chemicals may increase genotoxicity in industrial workers.

Adult↗
PubMed1999

A comparison of sampling and analytical methods for assessing occupational exposure to diesel exhaust in a railroad work environment.

Methods of assessing occupational exposure to diesel exhaust were evaluated in a railroad work environment. The American Conference of Governmental Industrial Hygienists (ACGIH)-recommended elemental carbon and respirable combustible dust methods of sampling and analysis for assessing diesel exhaust were included in the study. A total of 215 personal and area samples were collected using both size-selective (nylon cyclone and Marple) and non-size-selective samplers. The results demonstrate that the elemental carbon method is suitable for the railroad environment and the respirable combustible dust method is not. All elemental carbon concentrations measured were below the proposed ACGIH Threshold Limit Value (TLV) of 0.15 mg/m3. The concentrations of oxides of nitrogen (nitric oxide and nitrogen dioxide) were also found to be below their respective TLVs. There is no correlation between elemental carbon or respirable combustible dust and the oxides of nitrogen. The elemental carbon as fraction of total carbon is about 13 percent, except for onboard locomotives where it is about 24 percent. Comparison of elemental carbon and respirable combustible dust measurements showed consistent relationships for most sampling locations, with respirable combustible dust concentrations 12 to 53 times higher than the elemental carbon levels.

Data Interpretation, Statistical↗
PubMed2003

Assessment of the scientific basis for genetic testing of railroad workers with carpal tunnel syndrome.

In 2000, approximately 20 railroad track workers who filed injury reports or compensation claims for carpal tunnel syndrome were tested by their employer for two genetic traits to determine the work relatedness of the condition. The testing involved deletions, variants, or mutations in the genetic coding for peripheral myelin protein (PMP22) and transthyretin (TTR). This article is an assessment of whether there is a scientific basis for such testing. A review of the scientific literature indicated that neither the scientific basis nor the population validity of the PMP22 or TTR tests for carpal tunnel syndrome were adequately established before use on railroad track workers in 2000. Although ethical and legal issues may predominate in this case, the absence of a compelling scientific basis undermines the decision to conduct the tests.

Carpal Tunnel Syndrome↗
PubMed1985

Asbestos-related disease in railroad workers. A cross-sectional study.

A cross-sectional prevalence study of 377 railroad workers was carried out. The purpose was to investigate the prevalence of asbestos-related disease. We compared conventional with more recently adopted criteria for defining abnormal lung function. We compared the test results of those who performed reproducibly on spirometry with those who did not. Medical and occupational histories, flow-volume loops, and posteroanterior and lateral chest radiographs were obtained. Single-breath carbon monoxide diffusing capacity (DLCO) was measured, and chest auscultation was performed. Related to time since onset of exposure, pleural plaques occurred in 22.9%. There was radiographic evidence of interstitial disease in 1.6%. Reduced single-breath DLCO (12.4%), crackles (18.4%), and dyspnea (49.6%) were significantly associated with asbestos exposure. The prevalence of restriction and obstruction was 5.1 and 12.4%, respectively, but differed (p = 0.0001) with the definition criteria selected. The proportion with each of these abnormalities was higher in the nonreproducible group. That group was older, with more pleural plaques and chronic bronchitis. Railroad workers are a group at risk for asbestos-related disease. Extent of disease and assumptions about causality are likely to vary with definitions of normalcy and the use of reproducibility criteria.

Adult↗
PubMed1987

A case-control study of lung cancer and diesel exhaust exposure in railroad workers.

A case-control study of deaths among U.S. railroad workers was conducted to test the hypothesis that lung cancer is associated with exposure to diesel exhaust. Employed and retired male workers with greater than or equal to 10 yr of service who were born on or after January 1, 1900 and who died between March 1, 1981 and February 28, 1982 were eligible. We collected 87% of the death certificates from 15,059 deaths reported to the U.S. Railroad Retirement Board (RRB). Cases of lung cancer (1,256) were matched to controls by age (+/- 2.5 yr) and date of death (+/- 31 days). Potential exposure to diesel exhaust was assigned based on an industrial hygiene evaluation of jobs and work areas. Each subject's work history was determined from a yearly job report filed by his employer with the RRB from 1959 until death or retirement. Asbestos exposure prior to 1959 was categorized by the job held in 1959, the end of the steam locomotive era, or by the last job held if retirement occurred before 1959. Smoking histories were obtained by questionnaire from next of kin. Using multiple conditional logistic regression analysis to adjust for smoking and asbestos exposure, workers 64 yr of age or younger at the time of death with work in a diesel exhaust exposed job for 20 yr had a significantly increased relative odds (odds ratio = 1.41, 95% Cl = 1.06, 1.88) of lung cancer. No effect of diesel exhaust exposure was seen in workers 65 yr of age or older because many of these men retired shortly after the transition to diesel-powered locomotives.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗