Myoglobin production in emperor penguins.

Increased oxygen storage is essential to the diving capacities of marine mammals and seabirds. However, the molecular mechanisms underlying this adaptation are unknown. Myoglobin (Mb) and Mb mRNA concentrations were analyzed in emperor penguin (Aptenodytes forsteri) adults and chicks with spectrophotometric and RNase protection assays to evaluate production of their large Mb-bound O(2) stores. Mean pectoral Mb concentration and Mb mRNA content increased throughout the pre-fledging period and were 15-fold and 3-fold greater, respectively, in adults than in 3.5 month old chicks. Mean Mb concentration in 5.9 month old juveniles was 2.7+/-0.4 g 100 g(-1) muscle (44% that of wild adults), and in adults that had been captive all their lives it was 3.7+/-0.1 g 100 g(-1) muscle. The Mb and Mb mRNA data are consistent with regulation of Mb production at the level of transcription as in other animals. Significant Mb and Mb mRNA production occurred in chicks and young juveniles even without any diving activity. The further increase in adult Mb concentrations appears to require the exercise/hypoxia of diving because Mb concentration in captive, non-diving adults only reached 60% of that of wild adults. The much greater relative increase in Mb concentration than in Mb mRNA content between young chicks and adults suggests that there is not a simple 1:1 relationship between Mb mRNA content and Mb concentration. Nutritional limitation in young chicks and post-transcriptional regulation of Mb concentration may also be involved.

Severity of health effects associated with building-related illness.

Building-related illness ranges from mild rhinitis to potentially life-threatening hypersensitivity pneumonitis and legionellosis. Sick-building syndrome, consisting of headache, mucous membrane irritation, and fatigue, may be present in 30% of all office workers. Hypersensitivity pneumonitis, asthma, and legionellosis are less common, and it is difficult from existing studies to estimate the incidence of these more severe illnesses. There are even fewer data on an illness now being called multiple chemical sensitivity and its relationship to indoor environments. New studies are needed to estimate the frequency of all building-associated illnesses, and case definitions for these disorders must be delineated.

Variability in the classification of radiographs using the 1980 International Labor Organization Classification for Pneumoconioses.

This study describes the extent of agreement in classification of chest radiographs using the International Labor Organization (ILO) classification among six readers from the United States and Canada. A set of 119 radiographs was created and read by three Canadian and three US readers. The two ratings of interest were profusion (scored from 0/- to 3/+) and pleural abnormalities consistent with pneumoconiosis (scored with the ILO system, then collapsed into a yes/no). We used a number of approaches to evaluate interreader agreement on profusion and pleural changes, determining concordance, observed agreement, kappa statistic, and a new measure to approximate sensitivity and specificity. This study found that five of six readers had good fair to good agreement for pleural findings and for profusion as a dichotomous variable (> or = 1/0 vs < or = 0/1) using the kappa statistic, while a sixth reader had poor agreement. We found that concordance, expressed as percent agreement, was higher for normal radiographs than for ones that showed disease, and describe the use of the kappa statistic to control for this finding. This analysis adds to the existing literature with the use of the kappa statistic, and by presenting a new measure for "underreading" and "overreading" tendencies.

Fatal and non-fatal injuries from vessels under air pressure in construction.

Using a surveillance system that captures data on construction workers treated in an urban emergency department, we identified a series of injuries caused by vessels and tools under air pressure. We describe those six cases, as well as similar cases found in the Census of Fatal Occupational Injuries; we also review data from the National Surveillance for Traumatic Occupational Fatalities database and data from the Bureau of Labor Statistics. Among the injuries and deaths for which we had good case descriptions, the majority would have been prevented by adherence to existing Occupational Safety and Health Administration standards in the construction industry.

Injury surveillance in construction: injuries to laborers.

Construction is one of the largest industries in the United States, employing over 7.5 million people. It accounts for 3 times as many accidents as might be expected on a per capita basis. Laborers represent one of 15 job classifications participating in this industry. They have a higher risk of death or injury from a number of causes than do other construction workers.

Injury and employment patterns among Hispanic construction workers.

This article describes non-fatal injuries among Hispanic construction workers treated at an emergency department from 1990 to 1998. Medical and interview data were analyzed to evaluate and explain the workers' apparently inflated risk of injury. The majority of the injured Hispanic workers were employed in the less-skilled trades. Compared with other injured workers, Hispanics had a higher proportion of serious injuries and were disadvantaged in terms of training and union status. With the exception of union status, these differences largely disappeared after controlling for trade. The physical, financial, and emotional consequences were more apparent 1 year later for injured Hispanics, even after controlling for trade. These observations suggest that minority status is a predictor of trade and that trade is a predictor of injury risk. In addition to reducing injury hazards, interventions should address the limited employment and union membership options that are available to minority workers in the construction industry.

Bone marrow injury in lithographers exposed to glycol ethers and organic solvents used in multicolor offset and ultraviolet curing printng processes.

Prompted by referral of a printer with aplastic anemia, a study of possible marrow toxicity of workplace substances was undertaken. Dermal and respiratory exposures to dipropylene glycol monomethyl ether, ethylene glycol monoethyl ether, and a range of aliphatic, aromatic and halogenated hydrocarbons used for offset and ultraviolet cured multicolor printing were documented. Evaluation of seven co-workers revealed normal peripheral blood pictures, but bone marrow specimens demonstrated clear patterns of injury in three while the others had nonspecific signs of marrow effect. These changes could not be explained by known risk factors. The authors conclude that further evaluation of possible bone marrow toxicity resulting from exposure to glycol ethers and ultraviolet curing printing processes is warranted. More generally, we have provided data demonstrating that peripheral blood counts may be an insensitive tool for the study of hematologic toxins acting at the bone marrow level.

Effect of exposure to ethylene glycol ethers on shipyard painters: III. Hematologic effects.

Hemoglobin, hematocrit, red cell indices, total and differential white blood cell counts, and platelet count were measured in shipyard painters and control subjects as part of a cross-sectional, observational study of the effects of ethylene glycol ethers. Although the means of all variables were comparable between the groups, a significant proportion of painters were anemic (10%) and granulocytopenic (5%); none of the controls were affected. Review of company records documented that most of these abnormalities were acquired during employment; preexisting disease and other exposure could not explain the findings. These findings are consistent with prior animal studies and human case reports. Potential biases and confounding of the data are discussed.