Computed tomography of peripancreatic fat planes.

Obliteration of peripancreatic fat planes usually is considered an indicator of peripancreatic tumour infiltration in the presence of a malignant mass, or of inflammation of peripancreatic tissues in patients with pancreatitis. However, absence of peripancreatic fat planes also may be found in patients without evidence of pancreatic disease. Hence, CT scans of 125 patients without clinical or computed tomographic evidence of pancreatic disease were evaluated to assess normal variations in the anatomy of the pancreas and its relation to surrounding vessels and bowel loops. The fat plane separating the superior mesenteric artery from the pancreas was preserved in 100% of patients. Conversely, fat planes between the pancreas and the superior mesenteric vein, inferior vena cava, and adjacent bowel loops were partially or totally obliterated in 13% to 50% of patients. It is concluded that the absence of fat around the superior mesenteric artery is highly suggestive of pathologic changes of the pancreas, while the lack of fat planes between the pancreas and other splanchnic vessels or bowel loops frequently is normal, and therefore, is an unreliable sign of pancreatic disease. The applications of these findings to the assessment of tumour resectability by CT, and to CT scanning techniques, are discussed.

Incidence of Legionella organisms in selected Ontario (Canada) cities.

The distribution of Legionella pneumophila in water inside buildings was examined by means of culture methods. Cooling tower sumps and condenser valves harboured the organism at the highest frequency and in the highest concentrations. The bacterium was also frequently isolated from potable water systems, including hot and cold mixed taps, drinking water fountains and showers. When water quality parameters were examined, only elevated pH, total particulate nitrogen and alkalinity were correlated with the occurrence of L. pneumophila. Survival of the organism in water was increased at slightly basic pH and lower temperatures. The proliferation of the organism in water within buildings is probably due to a number of interrelated environmental factors that influence its survival and growth.

Characterization of chromatin-bound erythrocyte histone V (f2c). Synthesis, acetylation, and phosphorylation.

Synthesis and enzymatic modification of histone V was 1 order of magnitude lower in mature gander erythrocytes as compared with immature enriched cells hwich were capable of DNA synthesis. Application of shallow, linear gradient chromatography was used to demonstrate qualitative changes as well. This technique permitted the separation of newly synthesized and phosphorylated histone V from older, less phosphorylated molecules but did not discriminate between acetylated species. The most easily eluted fractions were those most recently synthesized, acetylated, and phosphorylated. While lysine chased into the other subfractions of histone V, phosphate did not, indicating a dephosphorylation step in the immature cells. Acetylation of histone V which occurs at a very low level was closely related to its synthesis. No differences in molecular weights or amino acid compositions were apparent, and behavior on polyacrylamide gels was similar to whole histone V. It is proposed that phosphorylation of histone V may play an important role in the modulation of the effect of histone V in immature cells on condensation and template restriction of chromatin which occurs in the terminal stages of differentiation of the avian erythroid cells.

Comparison of the surface structure, metal binding, and fecal coliform recoveries of nine membrane filters.

A comparative study was made of nine commonly used membrane filters from five manufacturers, all recommended for enumeration of coliform bacteria. Bacterial recoveries and flow rates were examined from three types of water and were found to correlate with the surface pore structure determined by scanning electron microscopy. The sorption of metals was also determined. The results of these studies indicate that the five best membranes for fecal coliform recovery could be placed in two groups: Millipore HC and Gelman, followed by Johns-Manville SG and AG and Sartorius 13806.

The relationship between three potential pathogens and pollution indicator organisms in Nova Scotian coastal waters.

Fifteen stations, in two estuaries, along the Northumberland Strait of Nova Scotia were examined between June and September 1981 for a relationship between the concentrations of commonly monitored fecal indicator bacteria and the potential pathogens Candida albicans, Pseudomonas aeruginosa, and Vibrio parahaemolyticus. Increased densities of these three organisms were usually associated with high densities of indicator bacteria. Whereas C. albicans and P. aeruginosa occur in human fecal wastes, V. parahaemolyticus is indigenous to the marine environment and positively responds to elevated nutrient levels in sewage. There is also some evidence that these bacteria survive as long or longer in marine waters than the common indicator bacteria. While membrane-filtration techniques for the enumeration of C. albicans and P. aeruginosa proved satisfactory, a V. parahaemolyticus membrane-filtration method lacked specificity and was supplemented by a most-probable-number method. In marine recreational and shellfish waters, these three organisms could complement fecal coliforms and fecal streptococci as indicators of human fecal contamination.

Skin testing with extracts of fungal species derived from the homes of allergy clinic patients in Toronto, Canada.

Airborne fungi in the homes of patients with allergic rhinitis or asthma, from a Toronto Allergy Clinic population, were isolated, quantified and identified to species. Allergen extracts were prepared from sixteen of these isolated species and used for skin-prick testing of twenty-six patients. Fourteen of the total patients reacted to one or more of these extracts at 1:10 (w/v) concentrations. The most common positive skin responses (8/14 to 6/14) were found for Cladosporium cladosporioides, Alternaria tenuis, C. sphaerospermum, and Fusarium sp. The two Cladosporium species were also most commonly isolated in homes, but A. tenuis and Fusarium sp. were found only in 4% and less than 1% of the air samples, respectively. Epicoccum purpurascens and C. herbarum, which were isolated on approximately 10% of the plates, showed fewer skin reactions compared with the above. Positive skin-test response to the other ten study extracts ranged from 5/14 for two species of Aspergillus and Phoma glomerata, to 1/14 for Penicillium viridicatum; of these species, Aspergillus fumigatus was isolated in 3% of the home samples, the others were less than 1%. The findings suggest that fungal antigens from species found in homes are commonly associated with skin sensitization in an allergy clinic population with upper or lower respiratory allergy. No specific relationships were found, however, between the prevalence of fungal species in the home environment and their prevalence as skin-test allergens.

Effects of activated carbon and bacteriostatic filters on microbiological quality of drinking water.

Three activated carbon filters for point-of-use water treatment were tested in laboratory and field studies for chemical removal and microbiological effects on water. All removed free available chlorine in municipally treated water to below the limit of detection, but removed only about 50 to 70% of the total available chlorine and 4 to 33% of the total organic carbon. Standard plate count bacteria in the effluent increased steadily with time for 3 weeks and remained elevated over the 8-week period of the study. Total coliform bacteria were found to persist and proliferate on the filters for several days after transient contamination of the influent water. Silver-containing activated carbon filters suppressed total coliform but not total bacterial growth. Pseudomonas aeruginosa was recovered from the effluents of all filters at some time during the tests.

Comparison of nine brands of membrane filter and the most-probable-number methods for total coliform enumeration in sewage-contaminated drinking water.

Nine different brands of membrane filter were compared in the membrane filtration (MF) method, and those with the highest yields were compared against the most-probable-number (MPN) multiple-tube method for total coliform enumeration in simulated sewage-contaminated tap water. The water was chlorinated for 30 min to subject the organisms to stresses similar to those encountered during treatment and distribution of drinking water. Significant differences were observed among membranes in four of the six experiments, with two- to four-times-higher recoveries between the membranes at each extreme of recovery. When results from the membranes with the highest total coliform recovery rate were compared with the MPN results, the MF results were found significantly higher in one experiment and equivalent to the MPN results in the other five experiments. A comparison was made of the species enumerated by these methods; in general the two methods enumerated a similar spectrum of organisms, with some indication that the MF method was subject to greater interference by Aeromonas.

A prospective study of swimming-related illness. I. Swimming-associated health risk.

During the summer of 1980, both swimmers and nonswimmers were enlisted in a prospective epidemiological study to determine the relationship between swimming, water quality, and the incidence of illness. Results of 4,537 telephone follow-up interviews showed that crude morbidity rates were 69.6 per 1,000 swimmers versus 29.5 per 1,000 nonswimmers. Swimmers experienced respiratory ailments most frequently, followed by gastrointestinal, eye, ear, skin, and allergenic symptoms, respectively.

A prospective study of swimming-related illness. II. Morbidity and the microbiological quality of water.

A prospective cohort epidemiological-microbiological study was carried out at 10 beaches in Ontario, Canada. Lake water and sediment samples collected at the beaches were analyzed for fecal coliforms, fecal streptococci, heterotrophic bacteria, Pseudomonas aeruginosa, and total staphylococci. Mean fecal coliform levels in the surface water of the lakes were within accepted guidelines. Bacterial densities were found to be approximately 10 times higher in the sediment than in the corresponding surface water samples. Morbidity among swimmers was shown to be related to staphylococcal counts, to fecal coliform levels, and, somewhat less strongly, to fecal streptococcal counts. Total staphylococci appeared to be more consistent indicators for predicting total morbidity rates among swimmers.

A comparative study of computed tomography and ERCP in pancreaticobiliary disease.

Fifty-seven patients with suspected pancreaticobiliary pathology constituting a clinical subset in whom the diagnosis was problematic or nonspecific were evaluated with computed tomography and ERCP. The relative sensitivities, specificities, and accuracies of the two tests were compared. Computed tomography was successful in obtaining a diagnostic examination in 100% and ERCP was technically successful in 75%. Both tests were equally accurate in detecting an abnormality (computed tomography 95.7%; ERCP 95.3%) and offering a correct diagnosis (computed tomography 72%; ERCP 70%). Sensitivity and specificity of the two tests for detection of an abnormality was computed tomography 100% and 91.3%; ERCP 91.7% and 100%. Sensitivity and specificity for the correct diagnosis was computed tomography 59% and 91.3%; ERCP 46% and 100%. Computed tomography was also superior to ERCP in making a correct diagnosis in pancreatic carcinoma (80% versus 63%) and pancreatitis (75% versus 50%). Based on these results we conclude that computed tomography utilizing high doses of intravenous contrast material and thin collimation is the preferred screening examination for pancreaticobiliary disease. ERCP should be reserved for those cases where the pancreaticobiliary disease. ERCP should be reserved for those cases where the diagnosis on computed tomography is obscure or uncertain and/or the pancreatic or biliary ductal anatomy requires direct contrast imaging.

Effect of chlorination on antibiotic resistance profiles of sewage-related bacteria.

A total of 1,900 lactose-fermenting bacteria were isolated from raw sewage influent and chlorinated sewage effluent from a sewage treatment plant, as well as from chlorinated and neutralized dilute sewage, before and after a 24-h regrowth period in the laboratory. Of these isolates, 84% were resistant to one or more antibiotics. Chlorination of influent resulted in an increase in the proportion of bacteria resistant to ampicillin and cephalothin, the increase being most marked after regrowth occurred following chlorination. Of the other nine antibiotics tested, chlorination resulted in an increased proportion of bacteria resistant to some, but a decrease in the proportion resistant to the remainder. Multiple resistance was found for up to nine antibiotics, especially in regrowth populations. Identification of about 5% of the isolates showed that the highest proportion of Escherichia coli fell in untreated sewage. Some rare and potentially pathogenic species were isolated from chlorinated and regrowth samples, including Yersinia enterocolitica, Yersinia pestis, Pasteurella multocida, and Hafnia alvei. Our results indicate that chlorination, while initially lowering the total number of bacteria in sewage, may substantially increase the proportions of antibiotic-resistant, potentially pathogenic organisms.