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C Camus

Publications and source records attributed to C Camus.

At least 37 records · Page 2Linked to original sources
PubMed1995

Identification of guanine exchange factor key residues involved in exchange activity and Ras interaction.

We have carried out a functional analysis of the human HGRF55 exchange factor in the yeast Saccharomyces cerevisiae. Twelve residues conserved among most of all known guanine exchange factors (GEFs) have been independently changed to alanine. Taking advantage of the ability of Hgrf55p to replace the yeast Cdc25p exchange factor, and using the two-hybrid system with RAS2ala22 allele, we have identified key residues for the interaction with Ras and/or its activation. Substitution of arginine 392 to alanine leads to a complete loss of interaction with Ras, though the protein remains stable. Substitution of Asp266 or Arg359 to alanine results in inactive proteins at 39 degrees C, still able however to interact with Ras. The other charged-to-alanine substitutions led to no detectable phenotype when present alone but most of them dramatically increased the temperature sensitive phenotype observed with [Asp266Ala] substitution. Surprisingly, the cysteine to alanine substitution in the highly conserved PCVPF/Y motif proved to be without effect, suggesting that the sulfhydryl group is not essential for stability or interaction with Ras.

Alanine↗
PubMed1995

Successful treatment of a brain abscess due to Trichoderma longibrachiatum after surgical resection.

A case of brain abscess due to Trichoderma longibrachiatum in a leukemic patient with prolonged neutropenia is reported. Definitive cure was achieved after neurosurgical resection of the abscess and prolonged antifungal therapy. Trichoderma is a filamentous fungus species, which is only exceptionally pathogenic in humans. This genus and particularly the species Trichoderma longibrachiatum should be added to the growing list of fungi causing infection in immunocompromised patients.

Adolescent↗
PubMed1995

[Cardiac tuberculoma; value of echocardiography and therapeutic management apropos of a case].

The authors report the case of a patient with a large mass in the right ventricle which was a tuberculoma without pulmonary disease. The severity of the right ventricular obstruction required surgical intervention with quadri-antitubercular therapy. Myocardial tuberculomas are very rare and usually reported as post-mortem findings. Only four cases resulting in cure have been previously reported. Current means of investigation such as echocardiography and endomyocardial biopsy allow rapid diagnosis of these tumours and should lead to better medical management with possible surgical intervention and a higher therapeutic success rate.

Adult↗
PubMed1995

[Yeast and the control of RAS by exchange factors].

Two isofunctional ras genes are present in the yeast Saccharomyces cerevisiae. Albeit their targets differ between mammals and yeast, they have conserved their regulators. The study of their positive regulators, guanine nucleotide exchange factors, have provided routes to the discovery of their regulatory elements in mammals. Ras are signal transducing proteins involved in the activation of the adenylate cyclase in yeast. They are activated by Cdc25p which has been shown to contain a Guanine Exchange Factor domain (GEF). SDC25, a gene partially homologous to CDC25, also contains a GEF domain but seems to be under a different regulation. It has been used to demonstrate the first guanine exchange activity on ras in vitro and was shown to be active by gene transfer in mammalian cells. Both Cdc25p and Sdc25p are associated to membrane and contain SH3 domains which are supposed to bind still unidentified proteins. Cdc25p is an unstable protein which contains a cyclin destruction box. Therefore activating effect on ras could be regulated by its level of expression. We have contributed to the isolation of a mammalian CDC25 homolog and we are analysing by directed mutagenesis key positions for ras activation of the human homolog HGRF55. That was performed by complementation analysis of yeast mutants as well as by use of two hybrid system. These approaches led us to the discovery of residues involved in ras interaction.

Animals↗
PubMed1995

[Infections on permanent endocavitary pacemaker leads: value of transesophageal echocardiography].

The prevalence of infection of permanent pacing material ranges from 0.13 to 19.9% of patients according to published series. The seriousness of this condition requires early diagnosis and treatment. Transesophageal echocardiography visualised vegetations on the intracardiac pacing lead in all of 11 patients studied, whereas transthoracic echocardiography and polynuclear leucocyte scintigraphy only provided positive diagnoses in 4 cases for each investigation. Three types of vegetation were visualised; no cases of tricuspid valve endocarditis were observed. Treatment was based on explantation of all implanted material by endovascular traction in 7 cases and by surgery in the other 4 cases according to the results of transesophageal echocardiography. There were no deaths or recurrence of infection. Transesophageal echocardiography is the investigation of choice for imaging a vegetation on an endocavitary pacing lead. Complete explanation is essential for a complete recovery of this infection.

Adult↗
PubMed1994

Two subclasses of guanine exchange factor (GEF) domains revealed by comparison of activities of chimeric genes constructed from CDC25, SDC25 and BUD5 in Saccharomyces cerevisiae.

Guanine Exchange Factor (GEF) activity for Ras proteins has been associated with a conserved domain in Cdc25p, Sdc25p in Saccharomyces cerevisiae and several other proteins recently found in other eukaryotes. We have assessed the structure-function relationships between three different members of this family in S. cerevisiae, Cdc25p, Sdc25p and Bud5p. Cdc25p controls the Ras pathway, whereas Bud5p controls bud site localization. We demonstrate that the GEF domain of Sdc25p is closely related to that of Cdc25p. We first constructed a thermosensitive allele of SDC25 by specifically altering amino acid positions known to be changed in the cdc25-1 mutation. Secondly, we constructed three chimeric genes from CDC25 and SDC25, the products of which are as active in the Ras pathway as are the wild-type proteins. In contrast, similar chimeras made between CDC25 and BUD5 lead to proteins that are inactive both in the Ras and budding control pathways. This difference in the ability of chimeric proteins to retain activity allows us to define two subclasses of structurally different GEFs: Cdc25p and Sdc25p are Ras-specific GEFs, and Bud5p is a putative GEF for the Rsr1/Bud1 Rap-like protein.

Amino Acid Sequence↗
PubMed1994

Role of endoglucanases in Erwinia chrysanthemi 3937 virulence on Saintpaulia ionantha.

The role of endoglucanases (endoglucanases Z and Y) in Erwinia chrysanthemi pathogenicity on Saintpaulia ionantha was assessed by mutagenizing cloned cel genes (celZ and celY) and recombining them with the chromosomal alleles. Strains with an omega interposon in celZ, a deletion in celY, or a double cel mutant were as virulent as the wild-type strain. However, in the strain with a deletion in celY, a delay in the appearance of symptoms was observed, and then maceration progressed as in plants infected with the wild-type strain, suggesting that E. chrysanthemi endoglucanases play a minor role in soft rot disease development.

Alleles↗
PubMed1994

[Liver transplantation with preservation of the inferior vena cava and "piggyback" reimplantation of the liver].

A modified technique of orthotopic hepatic transplantation with inferior vena caval preservation and piggy-back procedure is described. This procedure, used in 14 patients, avoided the need for temporary vena cava clamping in nine cases and reduced the need for venous bypass during orthotopic liver transplantation. The indications, results and advantages of this procedure are described.

Adult↗
PubMed1993

Sustained bacteremia in 26 patients with a permanent endocardial pacemaker: assessment of wire removal.

We reviewed the data on 26 patients with permanent endocardial pacemakers who had 28 episodes of bacteremia to determine whether removal of the wire is required. Patients recovered completely from the first episode in seven of 20 cases of staphylococcal bacteremia and in six of six cases of nonstaphylococcal bacteremia (P = .015). Definitive cure was not achieved during the first episode in seven cases of staphylococcal bacteremia related to the pacing system when the wire was not withdrawn; however, cure was achieved in five of six cases when the whole pacemaker was removed (P < .01). The duration of treatment was longer for the patients from whom the wire was not removed during the first episode (P < .01). Whether cases of staphylococcal bacteremia were related to the pacing system or not, the rate of recovery of the responsible microorganism from the wires was similar for both groups of patients (six [82%] of seven and three [75%] of four, respectively). Nonstaphylococcal bacteremia was unrelated to the pacing system in five of six cases; these patients were all cured without removal of the wire.

Aged↗
PubMed1991

Acute nondilated anuric obstructive nephropathy on echography: difficult diagnosis in the intensive care unit.

Renal echography (RE) is a well recognized, accurate, non-invasive imaging procedure for detecting urinary tract (UT) obstruction in Intensive Care Unit (ICU) patients: a dilated collecting system is usually present but a few cases of nondilated obstructive nephropathy have been previously described. We report the clinical, biological, imaging procedure data and outcome of 6 additional cases of anuric obstructive nephropathy without dilatation on one or more RE. All patients had previous and/or actual history suggestive of UT obstruction. Retrograde ureteropyelography (RUP) was performed in all of them: it provided the diagnosis of obstruction in 4 and was immediately followed by dramatic improvement of renal function in all, including the 2 patients with septic shock from proven or suspected UT origin. The cause of obstruction was a neoplastic retroperitoneal process in 4. We conclude that anuric nondilated obstructive renal failure is not uncommon and should be considered in anuric patients when UT obstruction is likely to occur. The sole visualization of a non-dilated collecting system on RE should lead to repeat RE, especially in hypovolemic anuric patients. RUP provided immediate diagnostic and therapeutic benefits in comparison with other imaging procedures in our series.

Aged↗
PubMed1991

Thrombotic thrombocytopenic purpura with the acquired immunodeficiency syndrome: a pathologically documented case report.

We report a patient with the acquired immunodeficiency syndrome (AIDS) in whom the acute onset of neurologic disorders and renal failure could be attributed to thrombotic microangiopathy. Clinical, biological, and pathological features were compatible with the diagnosis of thrombotic thrombocytopenic purpura (TTP). Such cases have been previously described, but histologically documented case reports are uncommon.

AIDS Dementia Complex↗
PubMed1990

[Anti-basement-membrane antibody mediated, rapidly progressive, glomerulonephritis. Diagnostic and therapeutic strategy based on a retrospective study of 14 cases].

Fourteen cases of anti-GBM antibody-induced RPGN were evaluated retrospectively in terms of renal function improvement and therapeutic risks. Nine men and 5 women (mean age: 55.3 years) were observed over a 9 year period; in three patients, hemoptysis was associated with renal disease (Goodpasture's syndrome). Most of these patients had received combinations of steroid therapy (ST), immunosuppressive drugs (IS) and plasma exchanges (PE). Age, duration of symptoms prior to diagnosis, initial renal function, therapeutic modalities and complications were assessed according to renal outcome: 9 patients (group A, "non-responders") remained on dialysis irrespective of the treatment administered; 5 patients (group B, "responders") recovered renal function. Complications, especially infections, were twice as frequent in group A. Two of the 4 recorded deaths were related to the disease or the treatment. Analysis of clinical and pathological values at the time of entry into the study for both groups indicated that oliguria/anuria, serum creatinine greater than 500 mumol/l and greater than 50% crescents, when associated, were factors predictive of poor renal outcome; in these patients, dialysis may be required except in cases of pulmonary hemorrhage. In all other patients, treatment with ST, IS and PE is recommended. Active hemoptysis necessitates pulse steroids or PE; if absent, further tests (carbon monoxide uptake, bronchoalveolar lavage, lung biopsy) are indicated before use of aggressive therapy.

Adrenal Cortex Hormones↗
PubMed1989

[Adult respiratory distress syndrome, a manifestation of severe pneumococcal infection].

A retrospective study analyzing the case notes of 49 hospitalized adults, either in intensive care (n = 26) or in thoracic medicine units (n = 23), for acute bacteriologically proven pneumococcal pneumonia based on samples obtained other than by sputum examination. The mortality was 54% in intensive care and 17% in the thoracic medicine unit. This significant difference may be explained in part by a respiratory distress syndrome in whom there were adequate criteria on admission for 7 patients in the intensive care group. Among these latter only one patient had had a splenectomy. The others did not have underlying disorders (three were chronic alcoholics); 7 patients were shocked on admission, four with a leukopenia less than 5,000/mm3 and six had a thrombocytopenia less than 100,000/mm3; finally 6 had a temperature of less than 38 degrees C. 7 patients died in less than four days (mean 2 days) in a clinical context of refractory hypoxemia. The significance of the respiratory distress syndrome is probably very different from the usual pneumonia; it seems rather to be an integration of the toxins induced by the pneumococcus. Its presentation can be particularly misleading as regards the diagnosis; the prescription of antibiotics once a diagnosis is obtained would seem insufficient by itself in this context to obtain a cure.

Adult↗