Biomedical subjects

N Paris

Publications and source records attributed to N Paris.

14 recordsLinked to original sources

PubMed2006

[Ecologic evaluation in the cognitive assessment of brain injury patients: generation and execution of script].

OBJECTIVE: Assessment of executive functions in an everyday life activity, evaluating brain injury subjects with script generation and execution tasks. MATERIALS AND METHODS: We compared a script generation task to a script execution task, whereby subjects had to make a cooked dish. Two grids were used for the quotation, qualitative and quantitative, as well as the calculation of an anosognosis score. We checked whether the execution task was more sensitive to a dysexecutive disorder than the script generation task and compared the scores obtained in this evaluation with those from classical frontal tests. Twelve subjects with brain injury 6 years+/-4.79 ago and 12 healthy control subjects were tested. The subjects carried out a script generation task whereby they had to explain the necessary stages to make a chocolate cake. They also had to do a script execution task corresponding to the cake making. RESULTS: The 2 quotation grids were operational and complementary. The quantitative grid is more sensitive to a dysexecutive disorder. The brain injury subjects made more errors in the execution task. CONCLUSION: It is important to evaluate the executive functions of subjects with brain injury in everyday life tasks, not just in psychometric or script-generation tests. Indeed the ecological realization of a very simple task can reveal executive function difficulties such as the planning or the sequencing of actions, which are under-evaluated in laboratory tests.

Adult↗

PubMed2005

[Self-evaluation of physical, cognitive and mood symptoms in a cohort of traumatic and vascular brain injury patients participating in social and neuropsychological remediation programmes].

INTRODUCTION: We studied 23 vascular or traumatic head injury subjects, five years after their injury. METHODS: Neuropsychological testing included language tests, memory performance, frontal lobe tests and standard tests of intelligence (QI). Behavior was evaluated with the neuropsychiatric interview (NPI). Using an analogic visual scale, subjects performed a self-evaluation of their memory, language, attention, physical and thymic complaints. RESULTS: Neuropsychological assessment was heterogeneous but seemed to show severe impairment. Mean NPI score was 31.4: 91 percent of patients showed depression or anxiety and 78 percent of them showed irritability. Mean memory and thymic complaints were scored 6 on the analogic visual scale. Thymic complaint was not correlated with neuropsychological tests but with physical complaints. Thymic complaint was correlated with NPI score. Language complaint was correlated with VIQ, attentional complaint was correlated with PIQ, memory complaint with memory tests. In a second part, we studied 21 patients again 6 months later and 14 patients 1 year later. Mean complaints were scored over 5 after 6 months and over 4 after 1 year. With neuropsychological remediation and social activities, memory complaints improved significantly after 6 months and attentional and thymic complaints after 1 year. CONCLUSION: Using of analogical visual scales appears to be feasible: patients were able to evaluate their difficulties. This could be useful to elaborate remediation programs and evaluate outcome.

Adult↗

PubMed2004

Protein localization in the plant Golgi apparatus and the trans-Golgi network.

This review presents plant-specific characteristics of the Golgi apparatus and discusses their impact on retention of membrane proteins in the Golgi or the trans-Golgi network (TGN). The plant Golgi consists of distinct stacks of cisternae that actively move throughout the cytoplasm. The Golgi apparatus is a very dynamic compartment and the site for maturation of N-linked glycans. It is also a factory for complex carbohydrates that are part of the cell wall. The TGN is believed to be the site from where vacuolar proteins are sorted by receptors towards each type of vacuole. To maintain the structure and specific features of the Golgi, resident proteins ought to be maintained in the proper Golgi cisternae or in the TGN. Two families of membrane proteins will be taken as examples for Golgi/TGN retention: (i) the enzymes involved in N-glycosylation processes and (ii) a vacuolar sorting receptor. Although the number of available plant proteins localized in Golgi/TGN is low, the basis of retention appears to be shared over all kingdoms and may result from pure retention and recycling mechanisms. In this review, we will summarize the characteristics of a plant Golgi and will discuss especially their consequences on on the study of this highly dynamic structure. We then choose membrane proteins with a single transmembrane domain to illustrate the signals and mechanisms involved in plants to localize and maintain proteins in the Golgi and the TGN.

Golgi Apparatus↗

PubMed2001

The internal propeptide of the ricin precursor carries a sequence-specific determinant for vacuolar sorting.

Ricin is a heterodimeric toxin that accumulates in the storage vacuoles of castor bean (Ricinus communis) endosperm. Proricin is synthesized as a single polypeptide precursor comprising the catalytic A chain and the Gal-binding B chain joined by a 12-amino acid linker propeptide. Upon arrival in the vacuole, the linker is removed. Here, we replicate these events in transfected tobacco (Nicotiana tabacum) leaf protoplasts. We show that the internal linker propeptide is responsible for vacuolar sorting and is sufficient to redirect the ricin heterodimer to the vacuole when fused to the A or the B chain. This internal peptide can also target two different secretory protein reporters to the vacuole. Moreover, mutation of the isoleucine residue within an NPIR-like motif of the propeptide affects vacuolar sorting in proricin and in the reconstituted A-B heterodimer. This is the first reported example of a sequence-specific vacuolar sorting signal located within an internal propeptide.

Amino Acid Sequence↗

PubMed2001

Regeneration of a lytic central vacuole and of neutral peripheral vacuoles can be visualized by green fluorescent proteins targeted to either type of vacuoles.

Protein trafficking to two different types of vacuoles was investigated in tobacco (Nicotiana tabacum cv SR1) mesophyll protoplasts using two different vacuolar green fluorescent proteins (GFPs). One GFP is targeted to a pH-neutral vacuole by the C-terminal vacuolar sorting determinant of tobacco chitinase A, whereas the other GFP is targeted to an acidic lytic vacuole by the N-terminal propeptide of barley aleurain, which contains a sequence-specific vacuolar sorting determinant. The trafficking and final accumulation in the central vacuole (CV) or in smaller peripheral vacuoles differed for the two reporter proteins, depending on the cell type. Within 2 d, evacuolated (mini-) protoplasts regenerate a large CV. Expression of the two vacuolar GFPs in miniprotoplasts indicated that the newly formed CV was a lytic vacuole, whereas neutral vacuoles always remained peripheral. Only later, once the regeneration of the CV was completed, the content of peripheral storage vacuoles could be seen to appear in the CV of a third of the cells, apparently by heterotypic fusion.

Base Sequence↗

PubMed2001

Demonstration in yeast of the function of BP-80, a putative plant vacuolar sorting receptor.

BP-80, later renamed VSR(PS-1), is a putative receptor involved in sorting proteins such as proaleurain to the lytic vacuole, with its N-terminal domain recognizing the vacuolar sorting determinant. Although all VSR(PS-1) characteristics and in vitro binding properties described so far favored its receptor function, this function remained to be demonstrated. Here, we used green fluorescent protein (GFP) as a reporter in a yeast mutant strain defective for its own vacuolar receptor, Vps10p. By expressing VSR(PS-1) together with GFP fused to the vacuolar sorting determinant of petunia proaleurain, we were able to efficiently redirect the reporter to the yeast vacuole. VSR(PS-1) is ineffective on GFP either alone or when fused with another type of plant vacuolar sorting determinant from a chitinase. The plant VSR(PS-1) therefore interacts specifically with the proaleurain vacuolar sorting determinant in vivo, and this interaction leads to the transport of the reporter protein through the yeast secretory pathway to the vacuole. This finding demonstrates VSR(PS-1) receptor function but also emphasizes the differences in the spectrum of ligands between Vps10p and its plant equivalent.

Blotting, Western↗

PubMed1998

Specific accumulation of GFP in a non-acidic vacuolar compartment via a C-terminal propeptide-mediated sorting pathway.

The green fluorescent protein (GFP) from Aequorea victoria can be detected in living plant cells after transient transformation of protoplasts. Expression of the GFP can be used to monitor protein trafficking in a mixed cell population and also to study the different function and importance of organelles in different cell types. We developed a vacuolar form of GFP that was obtained by replacing the C-terminal endoplasmic reticulum (ER)-retention motif of mGFP5-ER by the vacuolar targeting peptide of tobacco chitinase A. The vacuolar GFP was transported and accumulated in the vacuole as expected. However, we found two patterns of GFP accumulation after prolonged incubation (18-24 h) depending on the cell type. Most chloroplast-rich protoplasts had a fluorescent large central vacuole. In contrast, most chloroplast-poor protoplasts accumulated the GFP in one smaller vacuole but not in the large central vacuole, which was visible under a light microscope in the same cell. This differential accumulation reflected the existence of two different vacuolar compartments as described recently by immunolocalization of several vacuolar markers. We were able to characterize the vacuolar compartment to which GFP is specifically targeted as non-acidic, since it did not accumulate neutral red while acidic vacuoles did not accumulate GFP.

Androstadienes↗

PubMed1997

Molecular cloning and further characterization of a probable plant vacuolar sorting receptor.

BP-80 is a type I integral membrane protein abundant in pea (Pisum sativum) clathrin-coated vesicles (CCVs) that binds with high affinity to vacuole-targeting determinants containing asparagine-proline-isoleucine-arginine. Here we present results from cDNA cloning and studies of its intracellular localization. Its sequence and sequences of homologs from Arabidopsis, rice (Oryza sativa), and maize (Zea mays) define a novel family of proteins unique to plants that is highly conserved in both monocotyledons and dicotyledons. The BP-80 protein is present in dilated ends of Golgi cisternae and in "prevacuoles," which are small vacuoles separate from but capable of fusing with lytic vacuoles. Its cytoplasmic tail contains a Tyr-X-X-hydrophobic residue motif associated with transmembrane proteins incorporated into CCVs. When transiently expressed in tobacco (Nicotiana tabacum) suspension-culture protoplasts, a truncated form lacking transmembrane and cytoplasmic domains was secreted. These results, coupled with previous studies of ligand-binding specificity and pH dependence, strongly support our hypothesis that BP-80 is a vacuolar sorting receptor that trafficks in CCVs between Golgi and a newly described prevacuolar compartment.

Amino Acid Sequence↗

PubMed1996

Plant cells contain two functionally distinct vacuolar compartments.

The plant cell vacuole has multiple functions, including storage of proteins and maintenance of an acidic pH where proteases will have maximal activity. It has been assumed that these diverse functions occur in the same compartment. Here, we demonstrate that antibodies to two different tonoplast intrinsic proteins, alpha-TIP and TIP-Ma27, label vacuole membranes of two different compartments within the same cell. These compartments are functionally distinct, because barley lectin, a protein stored in root tips, is exclusively contained within the alpha-TIP compartment, while aleurain, a protease that serves as a marker for an acidified vacuolar environment, is exclusively contained within the TIP-Ma27 compartment. As cells develop large vacuoles, the two compartments merge; this may represent a process by which storage products in the alpha-TIP compartment are exposed to the acidic lytic TIP-Ma27 compartment for degradation.

Cell Compartmentation↗

PubMed1994

Purification and initial characterization of a potential plant vacuolar targeting receptor.

Clathrin-coated vesicles are known to be involved in the transport of proteins from the Golgi to the vacuole in plant cells. The mechanisms by which proteins are directed into this pathway are not known. Here we identify an integral membrane protein of approximately 80 kDa, extracted from clathrin-coated vesicles of developing pea (Pisum sativum L.) cotyledons, that bound at neutral pH to an affinity column prepared with the N-terminal targeting determinant of the vacuolar thiol protease, proaleurain, and eluted when the pH was lowered to 4. The protein was not retained on a control column prepared with the N-terminal sequence of a homologous, secreted thiol protease, endopeptidase B. The 80-kDa protein also accumulated in a membrane fraction that is less dense than clathrin-coated vesicles. In vitro studies demonstrated a binding constant of 37 nM between the approximately 80 kDa protein and the proaleurain targeting determinant. A peptide with a vacuolar targeting determinant from prosporamin weakly competed for binding to the approximately-80 kDa protein, while a peptide carrying a single amino acid substitution known to abolish prosporamin vacuolar targeting had no measurable binding affinity for the protein. The binding protein is a glycoprotein with a transmembrane orientation in which the C terminus is exposed to the cytoplasm. The binding domain is located in the N-terminal luminal portion of the protein. These properties of the binding protein are consistent with the function of a receptor that would select proteins in the trans-Golgi for sorting to clathrin-coated vesicles and delivery to the vacuole.

Amino Acid Sequence↗

PubMed1994

Health on wheels.

To adequately meet the needs of the poor and underserved, we must bring healthcare services to them. Saint Joseph's Hospital of Atlanta is doing just that through its Mercy Mobile Health Program. Even though Mercy Mobile has been available for a decade, the health status of Atlanta's homeless and working poor has deteriorated. The program has therefore increased its services to include primary care, disease prevention, health promotion, case management, and information and referral. With four vans and two mobile clinics, the program operates five days and three evenings a week, often in space donated by churches and other not-for-profit organizations. It provided more than 50,000 episodes of care last year. Developing strategies and resources to treat medically-at-risk, hard-to-reach clients with multiple diagnoses is a complex task, requiring the resources of more than one organization. One example of an effective collaborative effort is the "Street Home" program for HIV-infected homeless persons. This program, which provides early intervention and primary care to persons with HIV, is funded through the federal Ryan White "CARE" (Comprehensive AIDS Resources Emergency) Act.

Catholicism↗

PubMed1993

The vibration characteristics of chain saws and their influence on vibration white finger disease.

The vibration from chain saws can cause vibration-induced white finger disease (VWFD). Measurements of vibration levels on the front and rear handles of different chain saw-types, and on the operator's middle finger were collected at three logging camps on Vancouver Island. Factors effecting the vibration levels on the finger and handles were investigated. The acceleration at the firing frequency was found to be the dominant factor effecting handle and finger vibration. Other factors which were investigated were: grip force; the presence of handle covers; and chain sharpening procedure. Weighted acceleration levels are calculated and this information is used to assess the latency period for fallers to develop VWF disease.

Equipment Design↗

PubMed1993

Monoclonal antibodies against methionyl recombinant human prolactin.

Hybridoma cell lines producing monoclonal antibody (Mab) against recombinant human prolactin (rhPrl) were established from fusion between X63-Ag8 myeloma cells and Balb/c mice splenocytes. Four Mabs numbered I to IV were selected by ELISA, purified and characterized. All these Mabs were of the Ig1 kappa isotype and able to recognize oxidized as well as reduced rhPrl. As shown by a competitive inhibition assay, Mab IV did not compete with any of the three others. Moreover, both rhPrl and hPrl extracted from human pituitaries, were recognized equally by this Mab. Properties displayed by Mab IV make it very attractive for the evaluation of prolactin levels by sandwich immunoassays.

Animals↗

PubMed1990

Bacterial production and purification of recombinant human prolactin.

Escherichia coli cells transformed with a recombinant plasmid (pT7L) containing the coding sequence of human prolactin (hPrl) expressed a new protein. This protein, comigrating with human Prl on sodium dodecyl sulfate (SDS)-polyacrylamide gels, represented 50% of the total bacterial extract. Immunoprecipitation of [35S]methionine-labeled bacterial lysate with a rabbit antiserum to hPrl followed by SDS-polyacrylamide gel electrophoresis (PAGE) analysis showed that the major component had a Mr identical to that of standard hPrl. The majority of the recombinant hPrl (r-hPrl) accumulated in inclusion bodies. Analysis of these inclusion bodies by SDS-PAGE under nonreducing conditions showed that they are composed mostly of fully reduced monomers. Solubilization of the inclusion bodies and protein denaturation were performed in 8 M urea. Refolding during the renaturation procedure was confirmed by SDS-PAGE under nonreducing conditions. r-hPrl was further purified by gel permeation chromatography on a fast protein liquid chromatography column. More than 95% of the molecules were recovered as oxidized monomeric forms. The refolded molecule was tested for its bioactivity in the Nb2 lymphoma mitogenic assay. The dose-response curves obtained with either r-hPrl or pituitary-derived hPrl showed a complete parallelism. Furthermore, Nb2 cell proliferation was completely blocked by addition of hPrl antiserum to both preparations. Recombinant hPrl is identical to natural hPrl except for an additional methionine group at the amino terminal end.

Amino Acid Sequence↗