Is carbon monoxide a workplace teratogen? A review and evaluation of the literature.

Sixty case reports of carbon monoxide exposures involving pregnant women are reviewed. The circumstances under which carbon monoxide exposures adversely affected pregnancy and the types of effects seen are summarized. Severe acute exposures to carbon monoxide caused foetal death or toxic effects, including anatomical malformations and functional alterations. Foetal outcome was related to two major indices of carbon monoxide exposure: maternal blood carboxyhaemoglobin levels and maternal toxicity.

A comparison of the concepts used to develop and apply occupational exposure limits for ionizing radiation and hazardous chemical substances.

The rationales used by the American Conference of Governmental Industrial Hygienists (AC-GIH) to recommend exposure limits for 10 chemicals were reviewed. The 10 chemicals chosen were known to produce chronic disease after prolonged overexposure in the workplace. The chemicals were toluene diisocyanate, hydrogen fluoride, n-hexane, carbon disulfide, cadmium, inorganic mercury, cobalt, nitroglycerol, silica, and vinyl chloride. The rationales used by the International Commission on Radiological Protection (ICRP) to recommend limits for workplace exposure to ionizing radiation were reviewed. The rationales used in occupational health by ACGIH were then compared with those used by ICRP in health physics. The comparison revealed a significant divergence in the underlying concepts and philosophies of the two approaches. This divergence cannot be solely attributed to differences in scientific knowledge about toxicological and radiological effects. In areas of scientific uncertainty, exposure limits for ionizing radiation are based on worst case or conservative assumptions. This approach favors human safety. Parallel approaches could not be found for any of the 10 chemicals reviewed. Other factors such as the costs incurred by industry in meeting the proposed standards played a more significant role in establishing limits for workplace chemicals than for ionizing radiation.

A strategy for responding to information demands in occupational health.

The explosion in scientific information has created serious difficulties for data retrieval and utilization in occupational health. Ready access to pertinent, intelligible and useful information represents one of the most pressing problems in the field, not only for professionals but also for the clientele they serve. Effective information management is required for professionals to respond speedily and appropriately to requests for data and advice in occupational health. This paper describes a response strategy involving the collection, evaluation, presentation and dissemination of occupational health information and outlines the contribution and importance of information technology and information science to the area of occupational health.

Computerized information resources in toxicology and industrial health--a review.

The explosion in scientific information presents problems for toxicologists and industrial health specialists who need to respond rapidly and comprehensively to the information needs of the public, government and industry. The application of information technology enables large volumes of toxicology and industrial health information to be stored and retrieved through a variety of data-base resources. Three different categories of databases are described: dictionary, bibliographic and informational types. Examples of specific toxicology and industrial health databases within each category are given; their origin, style and content are reviewed. Specialists in the industrial health field are encouraged to improve their knowledge and literacy in the new disciplines of information technology and information science.

Cell characterization by use of multiple genetic markers.

The extensive use of cell cultures for diverse research purposes is one of the truly great international growth industries. With the proliferation of cells comes a responsibility for monitoring them for inter- and intraspecies characteristics. We use multiple genetic markers for cell identification, i.e. species specific antigens, isozymic phenotypes, chromosomal complement, and HL-A haplotypes. The methodologies employed are briefly described, and various examples cited to show how these markers can be utilized for cell line monitoring. Data are summarized from 275 cultures sent to our laboratory for analysis during the past eighteen months. The data show that, overall, 35% of the cultures received were contaminated. The majority of cell cultures submitted were human cell lines. We found that 36% of these cultures were cross contaminated; 25% by cells of another species and 11% by another human cell line. This high incidence of inter- and intraspecies contamination underscores the importance of frequent monitoring of cell cultures.

Essential thrombocythemia: a clonal disorder of hematopoietic stem cell.

We studied 5 patients with essential thrombocythemia utilizing glucose-6-phosphate dehydrogenase (G-6-PD) enzyme as a cell marker for determining clonality. One of the patients was found to be heterozygous for isoenzymes B and A in the nonhaemopoietic tissues such as fibroblasts, but manifested only isoenzyme type B in the erythrocytes, neutrophils, and platelets. Our studies support the concept that essential thrombocythemia is a clonal disorder arising in a multipotent stem cell.

Cell culture quality control by rapid isoenzymatic characterization.

Procedures that involve cell cultures require careful quality control to avoid inter- and intraspecies contamination. We have developed an electrophoresis technique that can be used routinely in cell culture laboratories to monitor cell line integrity. The method involves the isoenzymatic separation of nine polymorphic enzymes, three of which can be used for cell line species determinations and seven of which can be used for human cell line characterizations. Examples of how the system has been applied to both inter- and intraspecies identifications are described. The routine application of this protocol would be a valuable asset for laboratories concerned with establishing effective cell culture quality control.

Studies of glycine metabolism and transport in fibroblasts from patients with nonketotic hyperglycinemia.

Glycine transport in both normal and nonketotic hyperglycinemia fibroblasts was shown to occur by a sodium-dependent system. No significant difference could be detected in either the Km's (1.4 to 2.0 mM) or the Vmax's (6.2 to 16 nmole per mg protein per min) of the three control and three patient cell lines. Valine was a weak competitive inhibitor of glycine uptake. Ki's from both groups fell into the 5.6 to 5.8 mM range. Plasma levels of valine of one patient reached a maximum of 0.6 mM following a valine load. Glycine cleavage activity could not be detected in either control or nonketotic hyperglycinemia fibroblast lines. Serine utilization was the same in both nonketotic hyperglycinemia and control lines.

The uptake of 3-deoxy-3-fluoro-D-glucose by synaptosomes from rat brain cortex.

D-[3-3H]-3-deoxy-3-fluoroglucose was synthesized chemically and shown to be transported into rat brain synaptosomes by a saturable process with a Km 6.2 x 10(-4) M and a Vmax 2.8 nmole x mg protein-1. After an initial, rapid period of transport, further uptake of the fluorosugar is restricted by the rate of its phosphorylation. Both D-glucose and cytochalasin B are competitive inhibitors of 3-deoxy-3-fluoro-D-glucose transport with Ki values of 93 micron and 6.0 x 10(-7) M, respectively. Phloretin, N-ethylmaleimide and p-chloromercuribenzoate also inhibit the fluorosugar uptake, whereas ouabain and changes in K+, Na+, Mg2+ and Ca2+ ions have only a small effect. The recorded 3-deoxy-3-fluoro-D-glucose influx is slightly reduced by potassium cyanide, antimycin A, 2,4-dinitrophenol, and rotenone. The uptake reduction caused by these four reagents is relieved by the addition of exogenous ATP. The possible influence of hexokinse activity on the uptake process is discussed.