Standardized method for evaluation of hand disinfection by surgical scrub formulations

A standardized protocol for the evaluation of hand disinfection by surgical scrub formulations was applied to volunteers in a multicenter trial. Povidone iodine (PVI), chlorhexidine (CHX), and a nonmedicated soap (NMS) were tested. The scrubbing procedure involved three daily hand washings for five consecutive days; surviving bacteria were counted daily after being collected in a suitable neutralizing solution. Immediate efficacy (IE), cumulative efficacy (CE), and remanent effect (RE) were calculated by reference to the control hand. Statistical analyses of IE, CE, and RE showed significant differences among the three scrub formulations. IEs of PVI and CHX were equivalent and different from IE of NMS; CE and RE of CHX were higher than those of PVI and NMS. On the basis of the statistical analysis, the population size required for further studies aimed at detecting significant differences between surgical scrub formulations could be estimated.     

Sugars fermented byBifidobacterium infantis ATCC 27920 in relation to growth and α-galactosidase activity

Summary The ability of Bifidobacterium infantis ATCC 27 920 to ferment glucose, galactose, lactose, melibiose and raffinose was investigated with respect to -galactosidase (-d-galactoside galactohydrolase, E.C. 3.2.1.22). The sugars were tested at three concentrations: 0.5, 1.0 and 2.0%. The growth of B. infantis was slower on glucose compared with the other sugars. The highest specific growth rate was observed on melibiose followed by lactose. High cell numbers could be rapidly obtained on galactose-containing sugars. For each carbohydrate, enzyme activity was maximal at the end of the exponential phase and the highest specific -galactosidase activities were recorded on the two -1,6 galactosaccharides (melibiose and raffinose: 3.0 and 4.5 nkat · 10⁹ colony-forming units, respectively).Contribution no. 186 from the Food Research and Development Centre Offprint requests to: D. Roy     

Absence of genotoxic effects of nonasbestos mineral fibers

The biological activity of natural and synthetic mineral fibers has been examined. Natural attapulgite [(Mg, Al)₂Si₄O₁₀(OH).4H₂0], synthetic xonotlite [Ca₃Si₃O₈(OH)₂] and natural sepiolite [Mg₂Si₃O₈.2H₂O] were selected. Genotoxic effects were investigated by means of a well established cellular model based upon the measurement of unscheduled DNA synthesis (UDS) in rat hepatocytes in primary culture. The intrinsic capacity of the fibers (1 and 10 µ/ml) to induce UDS was first tested. None of the fiber types showed detectable UDS-eliciting activity. Also, the possible modulation of the cellular response to genotoxic agents by the materials was examined by exposing the cells to mixtures of 2-acetylaminofluorene (AAF) (0.05 and 0.25 µg/ml) and fibers (1 and 10 µg/ml). In these experiments, the UDS response was significantly diminished in the presence of xonotlite. This phenomenon may reflect changes in the uptake and/or metabolism of AAF or may result from an inhibition of DNA repair processes, the latter suggesting a possible cocarcinogenic potential for this synthetic silicate. These results point to the immediate necessity of studying more extensively the biological effects of fibrous materials that can be used as substitutes for asbestos.Abbreviations AAF 2-acetylaminofluorene - DMSO dimethyl-sulfoxide - FBS fetal bovine serum - IRDA Institut de Recherche et de Développement sur l'Amiante - LDH lactate dehydrogenase - UDS unscheduled - DNA synthesis - WME Williams' Medium E This work was supported by the Institut de Recherche et de Développement sur l'Amiante (IRDA), Sherbrooke, Canada.     

Immunophenotyping of mitotic cells from long-term cultures of chorionic villi

Chromosomal mosaicism in chorionic villus samples (CVS) may arise from different sources, such as clonal diversity within the chorionic tissue or contamination with maternal cells. To determine the origin of karyotyped cells, we compared the immunocytochemical features of mitotic cells in CVS long-term cultures with histological sections of their tissue of origin, i.e. chorionic villi. Immunolabelling of intermediate filaments specific for epithelial cells (cytokeratin) and mesenchymal cells (vimentin) established that mitoses yielded from CVS long-term cultures indeed stem from independently growing clones derived from both the epithelial and mesenchymal parts of the chorionic villi. Thus, mosaicism in CVS cultures may reflect true genetic heterogeneity within the biopsy. However, epithelial chorionic cells undergo in vitro metaplasia leading to co-expression of cytokeratins and vimentin. Fetal-specific immune markers (-HCG and SP1-glycoprotein) are not reliably expressed in CVS cell culture.     

Contribution of the different planktonic microbial assemblages to ETS activity in the Ligurian frontal area: north-west Mediterranean Sea

Spatial and size distribution of micro-organisms and their ETSactivity has been investigated in Ligurian Sea surface watersalong the Nice-Calvi transect across frontal areas from 18 to37 km offshore (TOMOFRONT 1 and 2 cruises, April 1988 and April-May1989 respectively). Aplastidic and plastidic nanoflagellatesand aplastidic picoflagellates were present in numbers closeto 0.25 x 10⁴ cells ml^–1, whereas plastidic picoflagellatesaccounted for about half this number. Correlations have beenevidenced between plastidic and aplastidic micro-organisms withinthe same size group, suggesting that they belong to a well-definedecosystem. The highest correlation between total ETS activityand abundance of the considered size groups was observed fornanoflagellates (r = 0.94, n = 22, and r = 0.90, n = 22 foraplastidic and plastidic cells respectively). The importanceof the role of nanoflagellates in surface waters, with respectto the overall ETS activity, was supported by results from sizefractionation which assigned to the 3–10 µm sizerange a 73.3% contribution to overall ETS activity. Resultsemphasize analysing global ETS activity of natural samples inorder to derive relationships between the different populationspresent in the sampled water. It is suggested that couplingflow cytometry to the ETS approach should be very helpful inthat respect.     

Propionate-induced synthesis of odd-chain-length fatty acids by Escherichia coli.

Exogenous propionate is incorporated in vivo by Escherichia coli as a primer to produce lipids with fatty acids of odd chain lengths. This provides a method for the specific labeling of the three terminal carbons in the fatty acyl chains of phospholipids.     

Peptide receptors in human lung tumor cells in culture: vasoactive intestinal peptide (VIP) and secretin interaction with the Calu-1 and SW-900 cell lines

We have investigated the interaction of VIP and secretin with two human lung carcinoma cell lines in cultures, SW-900 and Calu-1. ¹²⁵I-labeled VIP binds to and is inactivated by SW-900 and Calu-1 cells in a time- and temperature-dependent manner. The rates of binding and of inactivation were higher at 30°C than at 15°C. At equilibrium, native VIP competitively inhibited the binding of ¹²⁵I-VIP in the 10^?10?10^?7M range, half-maximal inhibition being observed at 1.2 nM in SW-900 cells and at 1.1 nM VIP in Calu-1 cells. Scatchard analysis indicated two classes of binding sites with similar characteristics in both cell lines. SW-900 cells have 27 600 sites with a high affinity ($\text{K}{}_{\mathrm{<mtext>d</mtext>}}\text{= 0.34}\text{nM}$) and 1062 000 sites with a low affinity ($\text{K}{}_{\mathrm{<mtext>d</mtext>}}\text{= 61.4}\text{nM}$). Calu-1 cells have 36 300 sites with a high affinity ($\text{K}{}_{\mathrm{<mtext>d</mtext>}}\text{= 0.33}\text{nM}$) and 1148 000 sites with a low affinity ($\text{K}{}_{\mathrm{<mtext>d</mtext>}}\text{= 78.6}\text{nM}$). Secretin inhibited tracer binding but with a 5000 times lower potency than native VIP in both cell lines.     

The zona pellucida binds the mature form of an oviductal glycoprotein (oviductin).

The use of a monoclonal antibody (MAb) specific for the oviductal zona pellucida (ZP) of the hamster has demonstrated that a new antigen (oviductin) is acquired by the ZP during transit of the oocyte in the oviduct. The epitope that is recognized by the MAb bears a terminal N-acetyl-D-galactosamine residue. We conducted a study in order to determine whether this immunoreactivity of the oviductal ZP results from the addition of the terminal sugar residue to a preformed ZP protein or from the transfer of the mature glycoprotein produced by oviductal secretory cells. We measured the incorporation of [35S]methionine into proteins using four different incubation systems: cumulus oophorus (CO) alone, CO in the presence of oviductal fluid, CO co-incubated with empty oviducts, and CO within intact oviducts. At the end of the incubation period, the ZP, vitelli, dispersed cumulus without oocyte, oviducts, and culture medium were isolated and analyzed for their protein content by sodiumdodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE), autoradiography, and immunodetection. The cumulus cells synthesized several proteins, independently of the oviductal environment; however, none of these proteins corresponded to oviductin. The ZP and the vitelli of cumulus oophorus that were incubated either alone or in the presence of oviductal fluid did not contain radioactive oviductin. When the oviduct (empty or intact) was present in the incubation system, radiolabeled oviductin was synthesized and secreted into the incubation medium. The ZP picked up a detectable amount of radioactive antigen only in the system in which intact oviducts were incubated.(ABSTRACT TRUNCATED AT 250 WORDS)     

Detection of Bifidobacterium species by enzymatic methods

The properties of Bifidobacterium strains of human origin were examined by three enzymic tests and the amounts of acetic and lactic acids produced were also quantified. It was evident that two strains of the American Type Culture Collection (ATCC) did not belong to the genus. Moreover, at least one strain of Bifidobacterium added to some milk preparations did not show distinctive characteristics of the genus. It was also shown that most of bifidobacteria studied produced alpha-galactosidase (EC 3.2.1.22) and alpha-glucosidase (EC 3.2.1.20). The presence of alpha-galactosidase could afford a rapid differentiation of bifidobacteria used in some dairy products since this enzyme was not detected in Lactobacillus strains studied.