Development and evaluation of methods to detect coliphages in large volumes of water

New and improved methods have been developed to detect somatic and male-specific coliphages in large volumes of water by single agar layer (SAL), enrichment and membrane filter methods. Somatic coliphages were detected efficiently on E. coli hosts C and CN13, male-specific coliphages were detected more efficiently on E. coli Famp than on Salmonella typhimurium WG49 and both types of coliphages were detected simultaneously on E. coli C3000. For water volumes of up to 100 ml, the SAL method was efficient and reliable. For water volumes of <1 L and as many as 10 multiple 1 L volumes, the enrichment method was efficient in detecting very low numbers of coliphages. Membrane filter methods, in which coliphages were adsorbed to and eluted from filters, also were relatively efficient, but they were less efficient than SAL and enrichment methods and were considered to be more cumbersome. For filter adsorption-elution methods, coliphage recoveries were most efficient for cellulose ester filters, less efficient for electropositive 1 MDS filters and least efficient for a direct membrane filter method. Overall, the enrichment method was preferred because of its ability to easily and rapidly detect low levels of coliphages in large sample volumes by either presence-absence or most probable number quantification.

[Clinico-statistical evaluation of the effects of cigarette smoke on the blood vessels of the lower extremities]

The relation between cigarette smoke and cardiovascular disease is well known. Several studies have shown that the adverse effect of carbon monoxide on the vascular endothelium is the most serious of the many factors associated with the damage caused by cigarette smoke. Two groups of patients were examined, one admitted for serious lower-extremity arteriosclerosis, the other composed of out-patients with symptoms referable to possible peripheral pathology. Invasive and non-invasive examinations were used to determine such pathology and relate it with cigarette smoking, in the absence of other greater vascular risk factors. The importance of cigarette smoke as a single vascular risk factor was further substantiated.