Biological hazards

This article outlines the biological hazards that nurses may face in their workplace. It hopes to inform nurses how they can reduce such hazards at work and contribute to a safer working environment.     

The radiological hazards of plutonium

About 1,500 tonnes of plutonium, 1,200 tonnes civilian, are now in world stockpiles, of which 200 tonnes have been separated from spent fuel in reprocessing plants. This will rise to 300 tonnes by the year 2000. Such reactor-grade plutonium contains a higher proportion of isotopes other than Pu-239, which progressively increases with longer burn-up. These isotopes have an increased risk of causing cancer, particularly if inhaled. Possible cancer rates from scattering of such plutonium in a city centre (e.g. by terrorist activity) are considered, and the implications of these calculations for the wisdom of continued reprocessing of spent nuclear reactor fuel are discussed.     

Anthropogenic sources of radiation hazards

0-/-B-hydroxyethyl/rutoside has been investigated for its effect on laser-induced thrombus formation in rat mesenteric venules and arterioles. The in vitro effect of this agent on platelet adhesion to bovine subendothelial extracellular matrix (ECM) and glass, on spreading and on platelet aggregation induced by ADP, collagen and epinephrine have also been studied. The animal investigations of 0-/-B-hydroxyethyl/rutoside showed an antithrombotic effect in doses between 5 and 50 mg/kg after i.v. injection. This effect was similar for both arterioles and venules damaged. After i.v. injection of minimum effective doses of 0-/-B-hydroxyethyl/rutoside, the antithrombotic effect lasted longer than 6 hrs but less than 12 hrs. In vitro, 0-/-B-hydroxyethyl/rutoside significantly inhibited platelet adhesion to bovine ECM in concentrations of 20 micrograms/ml PRP, and with 30 micrograms/ml the PRP adhesion to glass and spreading were inhibited. Epinephrine and ADP induced aggregation was inhibited in concentrations higher than 30 micrograms/ml PRP.     

Cutaneous hazards of the coast

Through recreational and commercial pursuits, more people than ever before are coming in contact with coastal waters containing a variety of bacteria, aquatic flora, and sea creatures potentially harmful to the skin. It is important for dermatology nurses to be aware of some of the more common cutaneous hazards related to the coastal environment as well as the basic treatment of these problems.     

Optical radiation hazards of welding arcs

Welding, a widely used industrial process, is one of the most intense artificial sources of optical radiation. Each type of welding process emits a different spectrum and intensity of optical radiation. For most processes, ultraviolet and visible radiation are the main components of the emission. Such factors as arc current, shielding gas, and base metal influence the emission spectrum. Adverse effects are confined to the skin and eyes, with welders suffering from a higher proportion of optical radiation associated eye conditions than do non-welders. Erythema is a common skin condition among welders, but conditions like skin cancer are rare. An evaluation of optical radiation from welding consists of determining an effective irradiance and a maximum permissible exposure duration, which can be very short (from seconds to minutes). Control measures include the use of screens to localize the hazards, and the use of personal protective equipment, such as protective clothing, safety spectacles, and welding helmets. Recent studies indicate that optical radiation can infiltrate into helmets and workers may be exposed to excessive levels. Overall, further investigation into adverse health effects and safety equipment design is warranted.     

Refractive hazards of intraoperative retinal photocoagulation

Coaggregations between bacterial species have been widely studied in vitro but not in the mouth. A new in vivo assay was used to measure the rate and composition of indigenous plaque formation onto bovine enamel chips covered with a continuous layer of bacteria. Chips were covered with Streptococcus oralis ATCC 10557, which coaggregated with many oral species, or Streptococcus gordonii S7, which did not coaggregate with these oral species, and placed in the mouth for 4 and 24 h. There were no differences in the number of most indigenous bacterial species isolated from the two streptococcal surfaces. However, the number of Actinomyces viscosus as a proportion of total Actinomyces spp. was significantly different on the two surfaces at 24 h. With the exception of Actinomyces naeslundii and A. viscosus removed from the S7 surface, all indigenous species increased significantly in number from 4 to 24 h, irrespective of the streptococcal surface. This study demonstrated that interbacterial coaggregation had only a limited effect on in vivo plaque development. Thus suggesting that environmental factors, growth or other adherence phenomena are dominant in in vivo plaque formation.     

Health hazards when using snuff

Snuff taking produces a white to yellowish, wrinkled lesion of the oral mucosa at the site where the quid is placed. The lesion is reversible, and only rarely exhibits dysplasia. Gingival recession and loss of attachment may occur in conjunction with the mucosal lesion. The risk of oral cancer varies greatly among the different published studies, from a relative risk of 48 to no increase in risk at all. Case control studies have found no association between oral tobacco and bladder cancer, whereas cigarette smoking carries a relative risk of about two. There appears to be no evidence for an association between oral snuff and cancer in general when the analysis takes into account confounders such as occupation, smoking and alcohol. The epidemiological evidence for an association with cardiovascular disease is contradictory. Snuff may probably cause hypertension, and one large study has reported a relative risk of 2 for dying of ischaemic heart disease. Biochemical evidence disfavors the hypothesis that snuff is atherogenic. In conclusion, the health hazards of oral moist snuff seem modest, and very much smaller than those of cigarette smoking.     

Egg substitutes: chemical and biologic evaluations

Cercariae of Diplostomum spathaceum dropped onto the eyes of small unanaesthetized rabbits penetrated through the cornea, crossed the anterior chamber, and entered the lens. After 2-3 weeks they died and became semi-permanent amorphous cataracts. Cercariae remaining in the cornea became the centres of stromal nebulae 0.1-0.2 mm across which remained visible for at least 3 months. Re-exposure produced marked conjunctival inflammation. Parasites applied to the eyes of large adult rabbits or cold-stored enucleated eyes of man entered the cornea but failed to penetrate as far as the anterior chamber. It is suggested that cercariae are unlikely to reach the lens of bathers because of the thickness of the human cornea. However, exposure to infection may result in temporary conjunctival inflammation and more persistant stromal nebulae. Cercariae of the closely related D. adamsi, did not penetrate or develop in the eyes of mammals.     

Molecular biologic markers and cancer risk assessment

BACKGROUND: Malignant melanoma is the second most common vulvar malignancy. The superficial inguinal lymph nodes are the main site of metastases. Endometrial metastasis of vulvar malignant melanoma has not been previously reported. CASE: Vulvar malignant melanoma was diagnosed in a 60-year-old, postmenopausal woman. Immunohistochemical stains were positive for vimentin and S-100 protein and negative for HMB-45. Six months following vulvectomy, right inguinal lymphadenectomy and immunotherapy, curettage was performed due to postmenopausal bleeding. Histologic and immunohistochemical examinations revealed metastatic malignant melanoma with the same staining reactivity as the primary vulvar neoplasm had. Hysterectomy and bilateral salpingo-oophorectomy was performed, disclosing invasion of the endometrium and the inner two thirds of the myometrium. CONCLUSION: Only 10 other cases of endometrial metastases from malignant melanoma have been previously reported. All those cases involved a primary tumor occurring in the trunk and extremities. This is presumably the first report on endometrial and myometrial metastases from vulvar malignant melanoma.