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Biomedical subjects

M Lalonde

Publications and source records attributed to M Lalonde.

At least 19 recordsLinked to original sources
PubMed2003

Comparative analysis of nutrition data from national, household, and individual levels: results from a WHO-CINDI collaborative project in Canada, Finland, Poland, and Spain.

STUDY OBJECTIVE: This project determined to what extent data on diet and nutrition, which were collected in a non-uniform manner, could be harmonised and pooled for international and national comparison. DESIGN: Direct comparisons of dietary data between studies were made using food balance sheets (FBS), household budget surveys (HBS), and individual dietary data (IDS); comparisons were also made within countries. Differences in study design and methodological approaches were taken into consideration. Data from research projects from the following four World Health Organisation (WHO) Countrywide Integrated Noncommunicable Disease Intervention (CINDI) countries were included-Canada, Finland, Poland, and Spain. MAIN RESULTS: FBS overestimated food consumption and nutrient intake compared to IDS. Results between HBS and IDS were quite similar, except for fish, meat, pulses and vegetables, which were underestimated by HBS, and sugar and honey and cereals, which were overestimated. Percentages of energy from fat, carbohydrates and proteins were higher when estimated from FBS, HBS, and IDS respectively. CONCLUSIONS: Results suggest that estimations from these three sources of dietary data are difficult to compare because they are measuring different levels of dietary information. The understanding of their relations may be important in formulating and evaluating a nutrition policy.

Adolescent↗
PubMed2001

Modulation of L-type Ca2+ channels in UMR 106 cells by parathyroid hormone-related protein.

The effects of rat parathyroid hormone-related protein (rPTHrP) and bovine and rat parathyroid hormone (bPTH and rPTH) on L-type Ca2+ channels in UMR 106 cells were investigated using the patch clamp technique. rPTHrP increased the whole cell L-type Ca2+ channel currents and the increase was concentration dependent. rPTHrP, at a concentration of 62.5 nM, increased the L-type Ca2+ channel current by 122+/-25%. bPTH was less potent. A concentration of 7.5 microM bPTH increased the current by 99+/-24%. Results obtained with rPTH were similar to those obtained using bPTH. Single channel measurements, using the cell-attached version of the patch clamp technique, showed an increase in both the number of channel openings and the mean open time when the cells were exposed to rPTHrP. This suggested that rPTHrP affected the gating of L-type Ca2+ channels in UMR 106 cells. This study demonstrates that the actions of bPTH and rPTHrP in UMR cells are mediated in part by extracellular Ca2+ entry. PTHrP, a paracrine agent important in development, is more potent in regulating Ca2+ entry than PTH.

Animals↗
PubMed2001

Fast and robust optic disc detection using pyramidal decomposition and Hausdorff-based template matching.

We report about the design and test of an image processing algorithm for the localization of the optic disk (OD) in low-resolution (about 20 micro/pixel) color fundus images. The design relies on the combination of two procedures: 1) a Hausdorff-based template matching technique on edge map, guided by 2) a pyramidal decomposition for large scale object tracking. The two approaches are tested against a database of 40 images of various visual quality and retinal pigmentation, as well as of normal and small pupils. An average error of 7% on OD center positioning is reached with no false detection. In addition, a confidence level is associated to the final detection that indicates the "level of difficulty" the detector has to identify the OD position and shape.

Algorithms↗
PubMed1993

Identification of endomycorrhizal fungi colonizing roots by fluorescent single-strand conformation polymorphism-polymerase chain reaction.

A method to identify arbuscular endomycorrhizal fungi based on the amplification of portions of the nuclear gene coding for the small subunit rRNA is presented. By coupling the sensitivity of the polymerase chain reaction and the specificity afforded by taxon-specific primers, a variety of samples can be analyzed, including small amounts of colonized roots. Family-specific primers as well as generic primers are described and can be used to amplify small subunit rRNA fragments from endomycorrhizal fungi by polymerase chain reaction. The amplified products are then subjected to single-strand conformation polymorphism analysis to detect sequence differences. Among the advantages of this approach is the possibility of directly identifying the fungi inside field-collected roots, without having to rely on the fortuitous presence of spores. This technique should have obvious applications in the study of arbuscular endomycorrhizal fungi populations and allow closer examination of their host specificity.

Base Sequence↗
PubMed1992

Effect of ABA on freezing resistance of Betula papyrifera and Alnus incana woody plant cell suspensions.

Treatment of birch (Betula papyrifera Marsh) and alder (Alnus incana (L.) Moench) cell suspension cultures with ABA increased the freezing resistance of the cells. After 7 days of treatment with 10(-5) M ABA, birch cells grown at 23 and 4 degrees C attained an LT(50) of -16.9 and -14.1 degrees C, respectively, whereas control cells had an LT(50) of -9.1 degrees C. In alder cell suspensions, treatment with 10(-5) M ABA at 23 degrees C induced a small increase in freezing resistance from -7.3 to -10.8 degrees C. Exposure to 4 degrees C alone did not induce a significant increase in hardiness in birch cell suspensions. Addition of 10(-5) M ABA to the medium inhibited fresh weight increase over 10 days of 3-g inocula of birch and alder by 70 and 52%, respectively. With the same concentration of ABA in the medium we found different intracellular ABA concentrations in 3- and 6-g inocula. We conclude that the concentration of ABA in the medium does not reflect the intracellular concentration of tissue cultures, and that cultural conditions may influence ABA accumulation by cell cultures.

Journal Article↗
PubMed1992

Rapid quantitation by PCR of endomycorrhizal fungi colonizing roots.

The VANS1/NS21 primer pair is useful for specifically amplifying a 550-bp ribosomal (r) DNA fragment from arbuscular endomycorrhizal fungi, directly from colonized root extracts. A procedure to quantitate these obligatory biotrophs rapidly, based on competitive PCR, was developed by constructing a suitable internal standard to be used with these primers. A 130-bp deletion in the Glomus mossae VANS1/NS21 amplified rDNA fragment was produced by amplifying separately external portions of that fragment, followed by ligation and amplification using the original external primers. When this deleted fragment was added to G. mossae rDNA, amplification using VANS1/NS21 primers yielded the two expected products of 430 bp and 550 bp, respectively, resolved by agarose electrophoresis. This fragment was cloned into the pCL1920 plasmid, a low-copy-number vector (five copies per cell), and mixed with the roots to be analyzed. This provides for a rapid quantitative assay because both steps--extraction of DNA from colonized roots and PCR amplification--are taken into account by the same internal standard. Using this procedure, a sample of colonized leek roots (Allium porum x Glomus vesiculiferum) was shown to contain 5 x 10(4) copies of arbuscular endomycorrhizal fungi rDNA genes per milligram of fresh weight.

Allium↗
PubMed1992

Specific amplification of 18S fungal ribosomal genes from vesicular-arbuscular endomycorrhizal fungi colonizing roots.

The first DNA sequences obtained from arbuscular endomycorrhizal fungi are reported. They were obtained by directly sequencing overlapping amplified fragments of the nuclear genes coding for the small subunit rRNA. These sequences were used to develop a polymerase chain reaction primer (VANS1) that enables the specific amplification of a portion of the vesicular-arbuscular endomycorrhizal fungus small subunit rRNA directly from a mixture of plant and fungal tissues. The specificity of this primer for arbuscular endomycorrhizal fungi was demonstrated by testing it on a number of organisms and by sequencing the fragment amplified from colonized leek (Allium porum) roots. This approach, coupled with other molecular techniques, will facilitate rapid detection, identification, and possibly quantitation of arbuscular endomycorrhizal fungi.

Allium↗
PubMed1991

Sequence of 18S rDNA of actinorhizal Alnus glutinosa (Betulaceae).

The small subunit ribosomal DNA for a woody actinorhizal, Alnus glutinosa, was isolated by the PCR method. Amplification products were cloned into the Bluescript SK- vector. Full sequence, 1698 bp, was obtained with NS1 to NS8 primers. Sequence alignments were made by UWGCG sequence data analysis computer programs. 18S rDNA sequence of A. glutinosa was compared to analogous segments of four other angiosperms, tomato, rice, maize and soybean. Sequence homologies are discussed and application for the technique is suggested.

Base Sequence↗
PubMed1987

Isozyme Variation among 40 Frankia Strains.

Forty Frankia strains belonging to the Alnus and Elaeagnus host specificity groups and isolated from various plant species from different geographical areas were characterized by the electrophoretic separation of isozymes of eight enzymes. All the enzyme systems that were investigated showed large variation. Diaphorases and esterases gave multiple band patterns and confirmed the identification of specific Frankia strains. Less variability was observed with enzymes such as phosphoglucose isomerase, leucine aminopeptidase, and malate dehydrogenase, which allowed for the delineation of larger groups of Frankia strains. Cluster analysis, based on the pair-wise similarity coefficients calculated between strains, delineated three large, dissimilar groups of Frankia strains, although each of these groups contained a large amount of heterogeneity. However, numerous Frankia strains, mainly from the Alnus host specificity group, demonstrated a perfect homology for all the enzymes tested.

Journal Article↗
PubMed1987

Psychosocial disadvantages associated with occupational hearing loss as experienced in the family.

A questionnaire has been developed to investigate the psychosocial disadvantages resulting from occupational hearing loss (OHL). It was designed to measure the awareness of the hearing disability, the coping strategies and the family response to the consequences of OHL. Answers to the questionnaire were obtained from 54 workers with various degrees of presumed OHL and from 44 normal-hearing workers employed in the same noisy plant. The results show that the family bears several consequences of the noise exposure and of the hearing loss of the worker and that its spontaneous reaction to OHL appears as one source of the psychosocial disadvantages experienced by the worker. The implications of these results for rehabilitative intervention are discussed.

Family↗
PubMed1985

Cloning of a multicopy plasmid from the actinorhizad nitrogen-fixing bacterium Frankia sp. and determination of its restriction map.

An 8.3-kb multicopy plasmid, pFQ31, from the nitrogen-fixing Frankia sp. strain ArI3, was cloned into Escherichia coli plasmid vectors and analysed physically. pFQ31 has no detectable sequence homology with another Frankia plasmid, pFQ32, which is present in the same host. Derivatives of pFQ31 with an antibotic resistance marker were introduced into Streptomyces lividans, which is taxonomically related to Frankia, but no stable replication could be achieved.

Actinomycetales↗
PubMed1983

Plasmids in Frankia sp.

A method to achieve cell lysis and isolate Frankia sp. plasmid DNA was developed. A screening of Frankia sp. strains belonging to different host compatibility groups (Alnus sp., Elaeagnus sp., Ceanothus sp.) showed that, of 39 strains tested, 4 (strains Cp11, ARgN22d, ArI3, and EUN1f) possessed plasmids ranging in size from 7.1 to 32.2 kilobase pairs as estimated from agarose gel electrophoresis and electron microscopy. A total of 11 plasmids were detected.

Actinomycetales↗
PubMed1978

Role of lectins in plant--microorganism interactions. IV. Ultrastructural localization of soybean lectin binding sites of Rhizobium japonicum.

The binding of purified, ferritin-labeled soybean seed lectin to the cell surfaces of Rhizobium japonicum 31 lb 138 has been examined by whole mount, thin section, and freeze-etch electron microscopy. The ferritin-labeled lectin binds in a biochemically specific manner to the capsular material of this bacterium. The lectin does not bind to the outer membranes of the cells or to flagella. Labeled lectin binds to sites throughout the capsular structure, although the density of labeling is somewhat greater on the outer surface of the capsule. Some cells appear to be partially encapsulated. Preservation of the capsular material proved difficult, and methods for retaining most of the capsular material were developed.

Binding Sites↗