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J Landry

Publications and source records attributed to J Landry.

105 records · Page 6Linked to original sources
PubMed1979

[Zein of maize grain. Preparation and characterization].

A laboratory procedure for isolation and purification of zein from grains of 4 varieties of Maize was described. The preparations were characterized by their physicochemical properties. Upon polyacrylamide gel electrophoresis in sodium dodecyl sulphate (SDS), native zein (from INRA 260 hybrid) was resolved into 2 major classes with average molecular weights of 45,000 and 22,000. After reduction with mercaptoethanol zein contained only two subunits of 22,000 and 24,000 daltons. Upon starch gel electrophoresis in 6 M urea at pH 3.5, native zein exhibited five major or medium intensity bands and several minor ones. The latter, under reducing conditions, disappeared to reinforce the major bands or to yield some new minor bands. Amino acid analysis revealed a very low content of lysine. The NH2-terminal amino acids were determined to be threonine and phenylalanine with a preponderance of the former. Zeins isolated from the varieties studied appeared tohave the same NH2-terminal residues and similar amino acid compositions with an arginine/histidine ratio ranging from 1.1 to 1.2. They differed in relative importance of components, detected by electrophoresis in the presence of SDS or urea. Changes in zein characteristics with the grain genotype allow one to conclude that the components of molecular weights of 22,000 and 24,000 consist of several subunits differing in charge and amino acid content.

Amino Acid Sequence↗
PubMed1979

Cell growth recovery after treatments at various supraoptimal temperatures.

The growth recovery kinetics of HeLa cells was investigated after treatments at intermediate (43-45 degrees) or high (49-55 degrees) supraoptimal temperatures for various periods of time (2 to 300 min) or after irradiations with nanosecond infrared CO2-laser pulses at energy densities equivalent to very high temperatures rises. After treatments at intermediate temperatures, single cells developed into colonies smaller than those obtained from nonheated control cells. Daily incorporations of pulsed [3H]thymidine in whole populations and microscopic observations of individual cell proliferation revealed a complex growth recovery for both survivors and dying cells. In contrast, colonies arising from cells treated at temperatures above 49 degrees do not differ in size from those developed from controls, and growth evaluations by [3H]thymidine and microscopy demonstrated that survivors resume normal proliferation immediately after treatments. The results which are supported by other studies on the effects of dose fractionation and metabolism status on cell survival are further discussed in relation to the "multistep" kinetic model for the cell response to hyperthermia.

Cell Division↗
PubMed1975

The relative rates of degradation of the plasma membrane glycoproteins from normal rat liver.

Rat liver plasma membranes, as fractionated by sodium dodecylsulfate/polyacrylamide gel electrophoresis, have been examined for the incorporation in their subunits of radioactive leucine, glucosamine and fucose. Specific spectra were obtained. In contrast to leucine, where the activity is distributed in many peaks all over the fractions, the glucosamine and fucose activities are found principally in the high molecular weight region. The relative rates of degradation of the glycoprotein components of the plasma membrane have been measured in normal liver using the double isotope technique. A marked heterogeneity of degradation was observed among the different subunits and a correlation between the rate of degradation and the size of the labelled subunits was found with glucosamine and fucose as well with leucine. This suggests a similar mode for the degradation of these membrane components.

Animals↗
PubMedDate not supplied

Albumins and globulins in developing maize grains.

Quantitative and qualitative (amino acid composition) changes of albumins and globulins in developing grain of normal and opaque-2 (o2) maizes were examined in proteins extracted sequentially with water and 0.5 M NaCl, and isolated by salting out with trichloroacetic acid. The amount of albumins per grain reached a maximum at mid-development the declined. Globulins, virtually absent in very young grain, increased in level until maturity. The variations were more marked for o2 than normal maize. Amino acid compositions changed little with development. The selectivity and exhaustiveness of sequential extraction, and the physiological role of albumins and globulins in grain are discussed.

Albumins↗
PubMedDate not supplied

Modulation of actin dynamics during stress and physiological stimulation by a signaling pathway involving p38 MAP kinase and heat-shock protein 27.

HSP27, like other proteins of the heat-shock protein family, accumulates to high levels after exposure of cells to a short period of hyperthermia and contributes to the development of a transient state of thermoresistance. In vitro, HSP27 behaves as an actin cap-binding protein and can inhibit actin polymerization. In vivo, the protective function of HSP27 is exerted mainly at the level of the microfilaments and appears as an extension of a normal function of the protein. This function is regulated by phosphorylation in a mitogen- and stress-sensitive signaling pathway involving the newly characterized p38 MAP kinase. The phosphorylation-modulated function of HSP27 can contribute to agonist-induced reorganization of the actin cytoskeleton and, in the case of stress activation, provides an actin-based adaptive response of cells to the new environmental conditions.

Actins↗
PubMedDate not supplied

Mammalian cells adapted to growth at pH 6.7 have elevated HSP27 levels and are resistant to cisplatin.

HSP27 levels are elevated in two Chinese hamster cell lines and in a human melanoma cell line adapted to growth at pH 6.7. The level of HSP72 is elevated in the melanoma cell line but not in the hamster cell lines adapted to growth at pH 6.7. HSC73 levels are not elevated in any of the adapted cell lines. Low pH adapted cells from all cell lines are resistant to cisplatin. It is proposed that elevated HSP27 levels in low pH-adapted cells may play a role in resistance to hyperthermia and resistance to cisplatin.

Adaptation, Physiological↗
PubMedDate not supplied

[Idiopathic hypereosinophilic syndrome: toward a new molecular-targeted therapy and a new cytomorphological and molecular definition].

Idiopathic hypereosinophilic syndrome is characterised by chronic hypereosinophilia leading to tissue damage, and after exclusion of reactive eosinophilia. Until recently no specific or efficient therapeutic was available. In 2003, a recurrent interstitial deletion 4q12 leading to the fusion of the FIP1L1 and PDGFRA genes was detected in hypereosinophilic syndromes. The resulting protein has constitutive tyrosine kinase activity which explains clinical and cytological remission of hypereosinophilic syndrome after treatment by a specific tyrosine kinase inhibitor, imatinib mesylate or Glivec, usually used in chronic myeloid leukaemia. Here we report a patient with hypereosinophilic syndrome associated to peculiar morphology of neutrophilic series and the 4q12 deletion. He presented clinical and haematological remission since the introduction of imatinib mesylate therapy.

Adult↗
PubMedDate not supplied

Patterns of care study decision tree and management guidelines for esophageal cancer. American College of Radiology.

PURPOSE: The Patterns of Care Study (PCS) of the American College of Radiology periodically develops a decision tree and current management guidelines for major malignancies where radiation has an important role. The decision tree is a framework which depicts the division of patients into treatment groups. The treatment guidelines are useful in management and also serve as a starting point for quality assessment. For the first time, PCS decided to develop consensus management guidelines for esophageal cancer. MATERIALS AND METHODS: A consensus panel was convened to define the key issues and develop guidelines for esophageal cancer management. A modified Delphi process was used to achieve consensus. RESULTS: The consensus panel developed guidelines for the management of patients with adenocarcinoma or squamous cell carcinoma of the esophagus with a Karnofsky performance status of over 50. Patients with clinical stage I or II esophageal cancer can be treated with curative intent using either a primary surgical or primary chemoradiation approach. For patients with clinical stage III malignancy, where the most common approaches are palliative, surgical resection is generally not recommended and chemoradiation is the preferred treatment. CONCLUSION: The PCS has developed treatment guidelines for esophageal cancer based on consensus committee deliberations. These guidelines can be useful for those who manage esophageal cancer.

Adenocarcinoma↗