A new semi-automated instrument to improve the fine needle aspiration procedure during breast lesion cell sampling

A large and increasing number of women in the western world will at some point during their life be investigated morphologically for some type of breast lesion. Fine Needle Aspiration (FNA) is one morphological method which is considered to be the fastest, cheapest and the most patient-friendly approach. However, the frequency of conclusive samples using this method varies and is often too low, especially when performed by unexperienced operators. In this study we have developed and tested a new semi-automated instrument (“CytoTest”) designed for FNA which is intended to improve the efficacy of the technique by increasing the percentage of conclusive samples. A total of 443 consecutive aspiration procedures on palpable breast lesions were performed to compare this new “CytoTest” equipment with the standard protocol using the same type of needles. We conclude that by increasing the extent and frequency of the reciprocatory motions used by an experienced sampling operator as well as enhancing the ejection pressure, the cellular yield can be increased almost three folded compared to the standard protocol. For cases with high amounts of non-diagnostic material (such as blood or cystic fluid) which were discarded, up to four times more sample could be obtained. Furthermore, the frequency of sparse samples under 1 mg was halved with use of the “CytoTest”.     

Surface properties of lactobacilli isolated from the small intestine of pigs

One hundred wild-type strains of the genus Lactobacillus were isolated from the small intestine of newly-slaughtered pigs up to 6 months of age. Cell surface hydrophobicity and capsule formation were studied on a number of strains. Strains showing high surface hydrophobicity as measured by the salt-aggregation test and hydrophobic interaction chromatography on Octyl Sepharose were commonly found to adhere in high numbers to isolated pig intestinal epithelial cells. Heat and protease treatment of bacteria of high surface hydrophobicity, including autoaggregating strains in phosphate-buffered saline, showed a drastic decline in this surface property. Three hydrophilic strains (LBp 1044, 1068 and 1073) also showed binding to intestinal cells but at a lower level (approx. 5 bacteria/cell) as compared with the best binding hydrophobic strain (LBp 1063, approx. 11 bacteria/cell). These findings suggest that different or multiple adhesion mechanisms may be involved in the colonization of the small intestinal mucosa of pigs. Cultures of selected strains grown in liquid media rich in carbohydrates did not affect their hydrophobic cell surface character. Therefore it seems less likely that carbohydrate capsule polymers are the major determinants of intestinal colonization of lactobacilli in pigs.     

Carbohydrate receptor specificity of K99 fimbriae of enterotoxigenicEscherichia coli

K99 Fimbriae from enterotoxigenicEscherichia coli (ETEC) were found to bind specifically to sialic acid, as measured in a haemagglutination inhibition assay using the intact bacteria and human erythrocytes. The affinity forN-glycolylneuraminic acid was about twice that ofN-acetylneuraminic acid (NeuAc), and other monosaccharides were found to be at least ten-fold less effective as inhibitors. The specificity was found to depend on electrostatic interaction where the carboxyl group and its orientation plays an important role. 2--Benzyl-NeuAc was a better inhibitor than 2--methyl-NeuAc suggesting a hydrophobic patch near the binding site on the protein. Axially oriented hydroxyl groups as in 4-epi-NeuAc and 3-hydroxy-NeuAc seemed to participate in binding since these derivatives were better inhibitors thanN-acetylneuraminic acid. K99 was found to have a higher affinity for 4-O-acetyl-NeuAc and lower affinity forN-acetylneuraminic acid withO-substituents at C7-C9 as compared toN-acetylneuraminic acid. Hence, the degree ofO-acetylation of sialic acid in the mucosa of the small intestine may influence colonization and determine susceptibility to infection.     

Autoaggregating Yersinia enterocolitica express surface fimbriae with high surface hydrophobicity

For 13 strains of Yersinia enterocolitica, there was a good correlation between the production of the broad-spectrum, mannose-resistant Yersinia haemagglutinin (MR/Y HA), the presence of fimbriae and high surface hydrophobicity. Each of these characters was expressed in cultures grown at low (less than 32 degrees C) but not at high (Greater than 35 degrees C) temperatures.     

Trophodynamics of the plankton community at Dogger Bank: predatory impact by larval fish

The trophodynamics of a coastal plankton community were studied,focusing on fish larvae and their copepod prey. The major objectiveswere to describe distributional overlap and evaluate the predatoryimpact by larval fish. The study was carried out across DoggerBank in the North Sea, August-September 1991. Sampling transectscrossed tidal fronts off the Bank and plankton at all trophiclevels showed peak abundance within frontal zones. Also Verticallythere was a significant overlap in distributional patterns ofthe plankton. Seven species of fish larvae were abundant, ofthese sprat (Sprattus sprattus) dominated. The abundance ofone group of fish larvae peaked in the shallow water close tothe Bank, whereas other species, including sprat, were foundin deeper water. Prey preference and predation pressure of fishlarvae were assessed using information on prey sizes and growthrates of larvae and the copepod prey. We estimated larval removalof preferred prey sizes to 3–4% day^–1, counterbalancedby a 3–7% day^–1' replenishment from copepod productionand growth. Additional predation pressure on copepods by aninvertebrate predator was estimated to 1–3%day^–1.In conclusion, the dynamics of fish larvae and other zooplankterswere closely linked. At peak abundances of fish larvae (>35mg dry weight m^–2), the accumulated predation on specificsize ranges of copepods, exerted by larvae and other predators,could exceed the ability of copepod replenishment and intra-/interspecificcompetition among predators might take place.     

High surface hydrophobicity ofStaphylococcus aureus as revealed by hydrophobic interaction chromatography

Hydrophobic interaction chromatography (HIC) on Octyl Sepharose^R in a column procedure was used to compare the relative surface hydrophobicity ofStaphylococcus aureus reference strains, protein A-negative mutants, and strains isolated from bovine mastitis. High protein A-producing strains (Cowan 1 and clinical isolate SA 17970) showed a higher relative surface hydrophobicity than did strains producing a low amount of protein A. One encapsulatedS. aureus strain (Smith diffuse) did not bind to the gel, while an unencapsulated variant showed binding properties similar to weak protein A-producing strains. Studies onS. aureus strains isolated from bovine mastitis revealed a good correlation between adsorption to Octyl Sepharose and the production of protein A. Results indicate that protein A and probably other surface proteins such as fibronectin-binding protein contribute to the high relative surface hydrophobicity ofS. aureus.     

Glycoconjugates as possible receptors forStreptococcus pyogenes

The adherence capacities of M-protein-positive (M+) and M-protein-negative (M-) strains ofStreptococcus pyogenes were compared in human epithelial cells obtained from the pharynx (PEC) or from the buccal mucosa (BEC). Adherence to PEC was related to the presence of M protein (40.5±1.1 M+ and 17.8±0.6 M–S. pyogenes per PEC), whereas BEC showed adherence equally for M+ and M– strains. Different receptor sites may thus be involved on the two cell types. Preincubation of the bacteria with disialogangliosides (1 mg/ml), orN-acetylgalactosamine, ord-galactose (10 g/ml) resulted in diminished adherence of M+ strains to PEC but not to BEC. Chromatography ond-galactose-Sepharose 6B showed specific binding only of M+ group A streptococcal strains to gel beads. M– group A, and groups C and G streptococci did not bind. These observations suggest that the receptors on PEC for group A streptococci are distinct from those on BEC, and that most probably the attachment ofS. pyogenes to human pharyngeal cells occurs by specific, lectin-like binding to galactose residues on epithelial cells.     

Enterotoxigenic Bacteria in Food and Water from an Ethiopian Community

Food and water samples from an Ethiopian community were screened for the presence of enterotoxin-producing bacteria. Using the Chinese hamster ovary cell assay, 40 of 213 isolates (18.8%) produced heat-labile (LT) enterotoxin. These LT-producing isolates comprised 33 of 177 (18.6%) strains from 24 of 68 food samples (35.3%) and 7 of 36 (19.4%) isolates of 4 of 17 water samples (23.5%). One LT-producing strain each of Salmonella emek and of Shigella dysenteriae was found. Three pseudomonads, all LT producers, produced heat-stable enterotoxin as gauged by the suckling mouse test. Two strains of LT-enterotoxigenic Escherichia coli O68 were found in water samples. No enterotoxigenic E. coli were isolated from food samples, but 13 of the LT-producing strains were Enterobacter, Klebsiella, Serratia, and Proteus species, and 7 food samples yielded more than one species of enterotoxigenic bacterium. Of the enterotoxigenic isolates from food, 15 were oxidase-positive strains of the genera Aeromonas, Pseudomonas, Achromobacter, Flavobacterium, and Vibrio. LT-enterotoxigenic Enterobacter, Acinetobacter, Klebsiella, Proteus, Providencia, and Serratia species represented 20 of the food and water isolates. Culture supernatant fluids of representative strains of oxidase-positive and oxidase-negative species giving positive reactions in Chinese hamster ovary cell tests induced fluid accumulation in rabbit ileal loops. Eight of the food samples and two of the water samples contained more than one isolate or species of enterotoxigenic bacterium. The stability of the LT production by oxidase-positive bacteria and non-E. coli strains was assessed by the rabbit skin and adrenal cell tests after 9 months and 1 year of storage, respectively, in Trypticase soy broth with glycerol at −70°C. Only 33% of the oxidase-positive strains were still LT enterotoxigenic. Of the oxidase-negative strains, 50 and 33% were LT producing at 9 months and 1 year, respectively. None of the E. coli isolates, both enterotoxigenic and nonenterotoxigenic, possessed K88, K99, or colonization factor antigen. The survey demonstrates the presence in food and water of enterotoxigenic bacteria of the same species as those isolated from cases of infantile diarrhea in the same community, although a correlation between these sources and infantile diarrhea remains to be established.     

Movement patterns of temperate wrasses (Labridae) within a small marine protected area

The movement patterns of three commercially important wrasse (Labridae) species inside a small marine protected area (~ 0.15 km²) on the west coast of Norway were analysed over a period of 21 months. The mean distance between capture and recapture locations varied between 10 and 187 m, and was species and season specific. The extent of movement was not related to body size or sex. These results imply that a network of small strategically located marine protected areas can be used as management tools to protect wrasses from size- and sex-selective fishing mortality.