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E Bain

Publications and source records attributed to E Bain.

18 recordsLinked to original sources
PubMed2001

Analysis of peptides synthesized in the presence of SAz-1 montmorillonite and Cu(2+) exchanged hectorite.

We have investigated the synthesis of oligopeptides containing glycine and tyrosine in the presence of the clay minerals montmorillonite (non-exchanged, SAz-1) and Cu(2+) exchanged hectorite. In both cases, homopolymers of the two amino acids are formed, as are mixed peptides. In the case of Cu(2+) hectorite, mixed oligopeptides up to trimers are detected in small amounts. For montmorillonite, heterogeneous oligopeptides up to hexamers are detected. Our experiments indicate montmorillonite is more effective in promoting oligopeptide formation than Cu(2+) hectorite. Analysis of the oligopeptide sequences formed on the montmorillonite surfaces indicates preferential synthesis of certain Gly-Tyr sequences over others.

Bentonite↗
PubMed1999

Preventing neural tube defects. Survey of preconceptional use of folic acid.

OBJECTIVE: To determine the proportion of women who take daily folic acid supplements in the month before conception and to identify factors associated with supplement use. DESIGN: Cross-sectional survey by self-administered questionnaire. SETTING: Tertiary care teaching hospital in Hamilton, Ont. PARTICIPANTS: Four hundred eighty-four (43%) of 1132 women who delivered normal babies between November 1997 and March 1998. MAIN OUTCOME MEASURES: Reports of daily vitamin supplement use in the month before pregnancy and after pregnancy, and having heard or read about the need to take folic acid before pregnancy; sources of information about folic acid; factors associated with preconceptional vitamin use. RESULTS: Thirty-four percent of respondents reported taking vitamins before conception (use ranged from 21% for those with unplanned pregnancies to 40% for those with planned pregnancies); 80% after conception. Of all respondents, 63% were aware of the need for preconceptional folic acid. Key information sources were family doctors and the mass media: the media were more important before conception, doctors after. Being older (30 years or more), having post-secondary education, and having a planned pregnancy were associated with knowing about the benefits of folic acid; knowledge, regular exercise, perceived good health, and planned pregnancy were associated with preconceptional use of vitamins. CONCLUSIONS: Even in this sample of well educated, English-speaking women, only one third took vitamin supplements before conception, which indicates that current educational efforts do not reach most women early enough. A coordinated, multi-pronged strategy that targets and involves physicians and capitalizes on opportunities to work with schools, public health outlets, and the media is needed.

Adolescent↗
PubMed1998

Evaluation of use of a new chromogenic agar in detection of urinary tract pathogens.

CHROMagar Orientation, a new chromogenic medium, was evaluated for the detection and differentiation of gram-positive and gram-negative pathogenic microorganisms in 900 urine samples from hospitalized patients. Performance characteristics of the medium were evaluated in comparison to those of 5% sheep blood and MacConkey agars by direct inoculation of the urine samples on the three media. Four gram-negative and two gram-positive strains as well as one yeast control strain from the American Type Culture Collection were used to ensure quality control. CHROMagar Orientation succeeded in detecting all the urine pathogens that were detected by the reference media, including gram-negative bacilli, staphylococci, streptococci, and yeasts. Colony color and morphology on CHROMagar Orientation accurately differentiated Escherichia coli, Proteus mirabilis, Proteus vulgaris, Pseudomonas aeruginosa, and Acinetobacter spp. Owing to the similarity in the pigmentation produced by Klebsiella, Enterobacter, and Citrobacter isolates, the medium failed to distinguish among them; however, these isolates were easily recognized as coliforms because of their metallic blue coloration. Staphylococci were clearly perceptible: S. aureus and S. epidermidis grow in regular-size colonies that range from opaque white to yellowish, and S. saprophyticus produces opaque pink colonies. All streptococcus strains, including those from groups B and C, were detected. They grow as undifferentiated flat dry diffused colonies, and additional tests were required for identification. Enterococci were easily discriminated by their strong turquoise pigmentation and their typical growth on the agar's surface. Yeast grow in typical creamy wet convex colonies. The accuracy of antibiotic susceptibility determinations according to standard methods was also tested by picking isolates directly from CHROMagar Orientation. The results showed excellent correlation with those obtained with microorganisms picked from reference media. Owing to the ease in differentiating mixed flora on CHROMagar Orientation, antimicrobic susceptibility tests were performed directly from primary isolates in all cases without the need for subcultures.

Agar↗
PubMed1980

Correlation of the growth of Chinese hamster V279-17lb multicellular spheroids with cytokinetic parameters.

The volumes of Chinese hamster V279-17lb multicellular spheroids grown in spinner culture were measured and correlated to DNA distribution and cell volume distribution information. Spheroid growth curves were obtained over a 21-day period using both electronic cell volume measurements and microscope micrometer sizing. The spheroids were collected from the aperture tube after electronic sizing, and single cell suspensions were prepared via trypsinization. Saline-washed cells were then stained with mithramycin and analyzed as unfixed or ethanol-fixed cells for both cell volume and DNA fluorescence measurements. Spheroid growth was determined to have an initial 8- to 9-day rapid growth phase, and a slow phase from 10 to 21 days. The single cell volume distributions of cells obtained from spheroids were dependent on spheroid volume and the relative proportions of small volume noncycling cells to large volume cycling cells comprising the spheroids were also dependent on spheroid volume. DNA distribution data and dual parameter DNA distribution cell volume contour patterns obtained for single cells dissociated from spheroids were closely related to the measured spheroid volume and revealed that the fraction of small, hypoxic G0-like cells was greatest in old, large spheroids.

Animals↗
PubMed1979

OER and RBE for negative pion beams of different peak widths.

Experimental data on survival curves for pion because of different peak widths under aerobic and hypoxic conditions are reported. Metabolic depletion of oxygen by the Chinese hamster cells (line V79) was used to obtain hypoxia. The results indicate that the RBE at the beam entrance (plateau) is approximately 1.0. When the Bragg peaks were broadened to widths of 1.3, 7.8, and 10.5 cm (at the 80% dose level), the RBE (50% cell survival) at the peak centres was 1.7, 1.6, and 1.2, respectively. The OER at the entrance was 2.4 compared with about 2.9 for X rays. The OER was independent of the survival level at which it was measured. The OER at the peak centres at widths of 1.3, 7.8, and 10.5 cm was 2.1, 2.4, and 2.2, respectively. These results indicate that, although the RBE at the centre of the 10.5 cm wide peak was significantly lower than at the centres of the 1.3 and 7.8 cm peaks, the OER values are similar for all peak widths used in this study.

Animals↗
PubMed1978

A heavy particle comparative study. Part II: cell survival versus depth.

Cell-survival measurements with depth of penetration were made for a series of incident doses of proton, helium, carbon, neon, argon, negative pion, neutron, and 60Co photon beams. Cultured human cells (T1) suspended in a gel-containing medium were used, and the measurements were found to be very useful in facilitating the design of ridge filters to produce iso-effects in the region of interest. Heavy charged particle beams (proton, helium, carbon, neon, and negative pion) were found to produce similar cell killing with depth of penetration. Because of saturation effects at higher LET, argon ions were less effective in killing aerated cells at depth, compared with other heavy charged-particle beams. Cell killing at depth in the region of interest, compared with that at the entrance, was not significantly different for single-field exposures when the Bragg peaks were broadened to cover a width of 10 cm. However, when two opposed fields with overlapping peaks were used, a large enhancement in killing was obtained in the peak region.

Argon↗
PubMed1978

A heavy particle comparative study. Part III: OER and RBE.

The results of a comparative study of heavy particles of interest in radiotherapy are reported in four parts. In this Part III, cell-survival measurements under aerobic and hypoxic conditions were made for various heavy particle beams. For heavy charged-particle beams, the measurements were made at the beam entrance (plateau), peak centre (10 cm wide peaks), and distal peak (1 cm from dose fall-off). Chinese hamster cells (V79) were used. Metabolic depletion was used to obtain hypoxia. The results indicate that the differences in RBE between the entrance region and peak are not very large when the Bragg peaks are broadened to 10 cm. The RBE for argon ions remains the same at the entrance and peak centre, and the RBE at the distal side of the Bragg peak is significantly reduced compared to the peak centre and entrance region because of saturation effects at high LET. The OER for protons is not significantly different from that for X rays. The OER for helium ions, carbon ions, and negative pions is larger, for neon ions is similar, and for argon ions is smaller when compared with fast neutrons. The OER values for heavy ions are higher than expected and could be due to a large delta-ray penumbra associated with the energy deposited by energetic heavy ions. The oxygen effect may depend upon energy deposition over distances of the order of nanometers.

Argon↗
PubMedDate not supplied

The interaction of biological molecules with clay minerals: a scanning force microscopy study.

We have used the technique of scanning force microscopy (SFM) to investigate the reaction of both amino acids and activated nucleotides in the presence of the clay mineral Cu(II)-exchanged hectorite. Using simulated prebiotic heating and wetting cycles, we have shown that the clay mineral acts to adsorb, concentrate, and subsequently catalyze the polymerization of these biological monomers into short peptides and oligonucleotides. The presence of the Cu(II) cations within the clay intergallery regions, and at surface step edges and cracks, is crucial for the observed reactions to occur. Clay minerals such as hectorite may have thus played an important role in the evolution of biologically viable molecules on the prebiotic earth.

Aluminum Silicates↗