Uses of workers' compensation data in epidemiology research

Contrary to general opinion, workers' compensation data can be helpful in epidemiologic research. Dr. Goldsmith assesses several studies based on data culled from workers' compensation or disability programs and explains how valuable information was derived.     

Race, ethnicity, and minority status

The paper discusses the problem about the ergonomic assessment of the abilities of the auditory analyzer for processing of speech information, depending on the zoning of the masking effect of noise and the degree of speech communication. A significant increase of the loss of speech information with rise of the intensities of the masking effect of noise (from 21.33% at L eq. 40 dB up to 96% at L eq. 90 and less than 90 dB/A/) is found. The speech communication is graded into 4 bands, depending on the qualitative-quantitative criteria of the processed speech communication. The regularity of the standard for masking noise (L eq. 65 dB/A), which guarantees good comprehensibility is proved from the aspect of ensuring the necessary conditions for speech information perception. Equivalent levels of masking noise near or equal to L eq. 85 dB/A/ ensure satisfactory comprehensibility at the control boards. The abnormal intensities of the masking noise effect are of particular importance as they belong to the inadmissible (bad) zone of auditory perception of speech information.     

The motor unit potential distribution over the skin surface and its use in estimating the motor unit location

Dextransucrase (DSRS) from Leuconostoc mesenteroides NRRL B-512F is a glucosyltransferase that catalyzes the synthesis of soluble dextran from sucrose or oligosaccharides when acceptor molecules, like maltose, are present. The L. mesenteroides NRRL B-512F dextransucrase-encoding gene (dsrS) was amplified by the polymerase chain reaction and cloned in an overexpression plasmid. The characteristics of DSRS were found to be similar to the characteristics of the extracellular dextransucrase produced by L. mesenteroides NRRL B-512F. The enzyme also exhibited a high homology with other glucosyltransferases. In order to identify critical amino acid residues, the DSRS sequence was aligned with glucosyltransferase sequences and four amino acid residues were selected for site-directed mutagenesis experiments: aspartic acid 511, aspartic acid 513, aspartic acid 551 and histidine 661. Asp-511, Asp-513 and Asp-551 were independently replaced with asparagine and His-661 with arginine. Mutation at Asp-511 and Asp-551 completely suppressed dextran and oligosaccharide synthesis activities, showing that at least two carboxyl groups (Asp-511 and Asp-551) are essential for the catalysis process. However, glucan-binding properties were retained, showing that DSRS has a two-domain structure like other glucosyltransferases. Mutations at Asp-513 and His-661 resulted in greatly reduced dextransucrase activity. According to amino acid sequence alignments of glucosyltransferases, alpha-amylases or cyclodextrin glucanotransferases, His-661 may have a hydrogen-bonding function.     

Clomiphene citrate in the management of male hypofertility: predictors for treatment selection

All males treated with long-term, low-dose clomiphene citrate retrospectively were categorized as having pregerminal, primary germinal, or postgerminal hypofertility and their response to treatment was observed. Among couples in which no female factor could be identified and the husband was categorized as demonstrating pregerminal hypofertility, a pregnancy rate of 42% was established after treatment.     

Isolated perfused lung--substrate utilization

Lung metabolism has been extremely difficult to determine in vivo primarily because the lung is overwhelmed by a great blood flow that generally makes the Fick principle inadequate. Largely for reasons such as this, investigators have had to rely on in vitro preparations. The isolated perfused lung has the apparent advantage of being similar to the lung in vivo when compared with other preparations. For instance, there is evidence that the capillary bed of the lung may alter substrates and influence their subsequent metabolism. Substrates have contact with the capillary endothelium in isolated perfused lungs but not to tissue slices, homogenates, or isolated cells. Our studies indicate that precursors of saturated phosphatidylcholine may include lipids, which are hydrolyzed in the capillary of the isolated perfused lung and thus become substrates such as free fatty acids, etc. However, tissue slices do not use the esterified lipids to the same extent, presumably because in this preparation the enzymes in the capillary endothelium do not have contact with the esterified lipids. Substrate utilization of the isolated perfused lung may be considerably altered by inflation of the lung or by pulmonary edema. Although glucose utilization and palmitate oxidation by the isolated perfused lung and by tissue slices of the rat lung are very similar, if the isolated perfused lung develops pulmonary edema, glucose utilization increases by nearly 100%. This phenomenon is apparently not due solely to fluid in the airspaces because in control studies with fluid added into the airways the glucose utilization did not increase to the degree observed with edematous lungs. Lung distention is associated with increased glucose consumption but marked distention is also associated with pulmonary edema. The effect of lung distension may be a direct effect or it may be secondary to the pulmonary edema.     

Subcutaneous fat necrosis following traumatic pancreatitis

Agranulocytosis and septicaemia developing in a patient with rheumatoid arthritis after 3 years' intermittent treatment with diclofenac, cimetidine and flucloxacillin for staphylococcal osteomyelitis is described. Treatment with recombinant granulocyte-colony-stimulating factor and high-dose methylprednisolone had no effect on the neutropenia which resolved on stopping all drug therapy. Relapse of agranulocytosis followed reintroduction of flucloxacillin and cimetidine 3 months later.     

Isolation and characterization of dendritic cells from mouse heart and kidney

Dendritic cells (DC) are thought to be distributed throughout lymphoid and most nonlymphoid tissues. Single cell suspensions were prepared from mouse hearts and kidneys. Subsets of MHC class II-positive (Ia+) leukocytes from both sources expressed markers such as CDw32 Fc receptors, F4/80, and complement receptor type 3 (CD11b/CD18). The capacity of these cells to initiate primary in vitro immune responses was assessed using oxidative mitogenesis and allogeneic mixed leukocyte responses. After fractionation by density centrifugation, cell sorting, immunomagnetic bead separation, or cell panning, the stimulatory activity of kidney cell suspensions was found to reside in the low density, Ia+ leukocyte fractions after overnight culture (day 1). In contrast, freshly isolated (day 0) cells had considerably less or no activity in these assays. However, depletion of Ia+ or CD45+ cells on day 0 followed by overnight culture removed the stimulatory activity on day 1. Therefore, day 0 kidney cells contain Ia+ leukocytes that can acquire or up-regulate their stimulatory activity during overnight culture. Similar observations were made for cells isolated from hearts, except that a population of uncharacterized nonleukocytes with stimulatory activity was detected on day 0 but not day 1. The phagocytic capacity of the leukocytes was then examined. Subsets of Ia+ cells phagocytosed zymosan, as shown by two-color flow cytometry and other immunofluorescence studies, and the zymosan-positive cells from kidney were able to initiate primary responses. Overall, these data demonstrate the existence of DC in kidneys and hearts, and suggest that in situ these cells resemble immature rather than mature DC.