PubMed Health⌕ Search

Biomedical subjects

C Navarre

Publications and source records attributed to C Navarre.

14 recordsLinked to original sources
PubMed2000

Membrane hyperpolarization and salt sensitivity induced by deletion of PMP3, a highly conserved small protein of yeast plasma membrane.

Yeast plasma membranes contain a small 55 amino acid hydrophobic polypeptide, Pmp3p, which has high sequence similarity to a novel family of plant polypeptides that are overexpressed under high salt concentration or low temperature treatment. The PMP3 gene is not essential under normal growth conditions. However, its deletion increases the plasma membrane potential and confers sensitivity to cytotoxic cations, such as Na(+) and hygromycin B. Interestingly, the disruption of PMP3 exacerbates the NaCl sensitivity phenotype of a mutant strain lacking the Pmr2p/Enap Na(+)-ATPases and the Nha1p Na(+)/H(+) antiporter, and suppresses the potassium dependency of a strain lacking the K(+) transporters, Trk1p and Trk2p. All these phenotypes could be reversed by the addition of high Ca(2+) concentration to the medium. These genetic interactions indicate that the major effect of the PMP3 deletion is a hyperpolarization of the plasma membrane potential that probably promotes a non-specific influx of monovalent cations. Expression of plant RCI2A in yeast could substitute for the loss of Pmp3p, indicating a common role for Pmp3p and the plant homologue.

Adenosine Triphosphatases↗
PubMed1999

[Patients in a state of agitation at the admission service of a Rouen hospital emergency department].

OBJECTIVE: To determine the incidence and causes of agitation states in patients presenting at the Rouen University Hospital emergency room and to analyze the management scheme. PATIENTS AND METHOD: A prospective study was conducted over a 9 month period in 100 consecutive patients presenting a state of agitation assessed using the Overt Aggression Scale. A pre-planned management protocol was applied. RESULTS: The incidence of states of agitation was 0.56%. There were 43 women and 57 men, mean age 33 years. Most of the agitated patients were admitted between 6 p.m. and 4 a.m. (69%). Over the 9 month period, 2 patients were admitted twice for agitation and 2 absconded. Low glucose level was the cause of agitation in 4 cases. Alcohol and/or drug use concerned 73% of the agitated patients and was the most frequently observed triggering factor (17%). Only 6% of the patients had a regular employment. Physical restraining measures and sedation were required in 86% and 84% of the cases respectively. Among 67 patients given loxapine for sedation, 2 developed acute dyskinesia and 9 low blood pressure. One out of 4 patients were referred to a psychiatric unit. CONCLUSION: Patients in a state of agitation are young, often female, and in a difficult socio-economic situation. Hypoglycemia is the main differential diagnosis. A triggering factor can often be identified. A state of agitation is not a repetitive condition but occurs as a short-lived episode in the patientís history. Such patients need rapid care to avoid further aggravation and disruption of the emergency room activity, and to prevent the patient from fleeing. Loxapine provides effective sedation but requires regular monitoring of blood pressure and can provoke acute dyskinesia in young subjects.

Adult↗
PubMed1999

[Diagnosis and management of anxiety in victims of psychological trauma].

Management of psychic injury has been developing in France recently. Community catastrophies like wars or natural events, individual's stress are more and more related. Physicians are qualified for the treatment of their psychic consequences. Family doctors know people and local geographic situations and are often the first medical managers on the scene of the disaster.

Anxiety Disorders↗
PubMed1994

Two distinct genes encode small isoproteolipids affecting plasma membrane H(+)-ATPase activity of Saccharomyces cerevisiae.

A small proteolipid called PMP1 is associated with yeast plasma membrane H(+)-ATPase (Navarre, C., Ghislain, M., Leterme, S., Ferroud, C., Dufour, J.-P., and Goffeau, A. (1992) J. Biol. Chem. 267, 6425-6428). We have identified a second Saccharomyces cerevisiae plasma membrane proteolipid gene by hybridization with a PMP1 probe. The sequence of the corresponding gene, called PMP2, is 92% identical to the PMP1 gene sequence. PMP2 encodes a 43-amino acid polypeptide that can be extracted from the membrane with chloroform/methanol. The two proteolipids differ at residue 21, which is an alanine in PMP1 and a serine in PMP2. The two PMP genes are similarly expressed in the wild-type strain, and no modification of the level of transcription of one PMP gene is detected in a strain deleted of the other. A regulatory function of the proteolipids is indicated by the observation that a strain lacking both PMP genes and no longer containing plasma membrane proteolipids displays a lower Vmax of the plasma membrane H(+)-ATPase activity.

Adaptor Proteins, Signal Transducing↗
PubMed1992

Purification and complete sequence of a small proteolipid associated with the plasma membrane H(+)-ATPase of Saccharomyces cerevisiae.

The purified plasma membrane H(+)-ATPase of Schizosaccharomyces pombe and Saccharomyces cerevisiae display, in addition to the catalytic subunit of 100 kDa, a highly mobile component, soluble in chloroform/methanol. Chloroform/methanol extraction of S. cerevisiae plasma membranes led to isolation of a low molecular weight proteolipid identical to that present in purified H(+)-ATPase. NH2-terminal amino acid sequencing revealed a 38-residue polypeptide with a calculated molecular mass of 4250 Da. The polypeptide lacks the first two NH2-terminal amino acids as compared with the deduced sequence of the PMP1 gene (for plasma membrane proteolipid) isolated by hybridization with an oligonucleotide probe corresponding to an internal amino acid sequence of the proteolipid. The polypeptide is predicted to contain an NH2-terminal transmembrane segment followed by a very basic hydrophilic domain.

Amino Acid Sequence↗
PubMedDate not supplied

1H- and 2H-NMR studies of a fragment of PMP1, a regulatory subunit associated with the yeast plasma membrane H(+)-ATPase. Conformational properties and lipid-peptide interactions.

PMP1 is a 38-residue polypeptide associated with the yeast plasma membrane H(+)-ATPase, found to regulate the enzyme activity. To investigate the molecular basis of the PMP1 biological function, the conformational properties of a synthetic PMP1 fragment, A18-F38, comprising the predicted C-terminal cytoplasmic domain and a part of the transmembrane anchor have been studied by 1H- and 2H-NMR spectroscopies. High resolution 1H-NMR experiments showed that, in deuterated DPC micelles, the A18-G34 segment adopts a well defined helix conformation. Our data suggest that the whole PMP1 molecule forms a unique helix whose axis might be slightly tilted with respect to the bilayer normal. Protonated DPC, DMPC and DMPS were incorporated in deuterated micelles containing the PMP1 fragment for studying lipid-peptide interactions. Unusually strong and selective intermolecular NOEs between lipid chain and peptide side chain protons, especially those of the unique Trp residue, were observed. Solid state 2H-NMR experiments performed on pure deuterated POPC and mixed deuterated POPC:POPS (5:1) bilayers revealed that the PMP1 fragment specifically interacts with negatively charged PS lipids.

Amino Acid Sequence↗
PubMedDate not supplied

[Hypersensitivity to glucocorticoids: reflections on a published case report sample].

Hypersensitivity reactions associated with glucocorticoid treatment are rare but well known; the purpose of this study was to identify the responsible constituent (the excipient or the glucocorticoid). 32 cases published from 1970 have been analysed. In 75 per cent of cases, the patients received the glucocorticoid (hydrocortisone and methylprednisolone principally) by the intravenous route. Clinical manifestations reported were respiratory or cutaneous, with a short interval to onset. Skin tests were performed in 20 patients, but cutaneous challenge identified an agent responsible for hypersensitivity in only three cases. The heterogeneity of the test results in these 32 cases makes it difficult to identify a unifying explanation for the reactions, or propose a therapeutic schedule.

Adolescent↗
PubMedDate not supplied

[Anxiety and medicine: what is the role of the psychiatrist?].

The relationship between medicine and psychiatry is complex and sometimes a little difficult. Anxiety is frequently met in somatic medicine units and particularly in General Hospital where psychiatrists are often required for crisis situations. So, anxiety disorder becomes a link between physicians and psychiatrists looking after same inpatients. Epidemiological high comorbidity too is demonstrated between anxiety and somatic disorders. More and more frequently, psychiatrists are engaged for care of post traumatic stress disorders. In fact, in modern medicine, the psychiatrist is collecting medical, psychosocial and humanist points of view. His missions of clinician, teacher, and researcher seem really important for the future evolution of medicine.

Anxiety Disorders↗