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C Morin

Publications and source records attributed to C Morin.

At least 19 recordsLinked to original sources
PubMed2006

A spontaneous albino mutant of Ceratocystis resinifera results from a point mutation in the polyketide synthase gene, PKS1.

We characterized a spontaneous albino mutant of Ceratocystis resinifera. Compared with the wild-type progenitor strain, the albino mutant had a reduced linear growth on culture medium, but its growth on lodgepole pine sapwood was unaffected. The albino mutant did not produce any coloured pigment on agar media or wood. However, upon exposure to exogenous scytalone, an intermediate metabolite of the melanin pathway, the production of a brownish melanin was restored. This suggests that the albino phenotype resulted from a mutation affecting the melanin synthesis pathway, upstream of the scytalone synthesis step. Melanin production was restored in the mutant by transforming it with a wild-type copy of the Ceratocystis resinifera polyketide synthase gene, PKS1. The complemented transformants produced melanin, indicating that the PKS1 gene was defective in the albino mutant. Sequence analysis revealed that the PKS1 allele found in the albino contained a single point mutation that resulted in an amino acid change from serine to proline at the 3' end of the beta-ketoacyl synthase motif.

Amino Acid Sequence↗
PubMed2005

[Salmonella infections in children: a retrospective study over a four-year period].

OBJECTIVES: Epidemiological state of salmonella infections in Languedoc-Roussillon (France) and discussion of therapeutic indications. MATERIAL AND METHOD: Retrospective study over a four-year period of paediatric salmonella infections requiring hospitalisation in Montpellier University Hospital. Analysis of clinical, bacteriological, laboratory and therapeutic data. RESULTS: One hundred and sixty nine cases of paediatric salmonella infections have been investigated. The clinical triad consisted of diarrhea, abdominal pain and fever. Six severe cases have been observed and seemed to have been independent of patient's background. Laboratory findings showed inconstantly hyperleucocytosis and increase in CRP levels. Stool analysis remained the reference laboratory test to detect salmonella. Two major strains of salmonella have been identified: Salmonella enterica subsp. enterica serovar Typhimurium and Enteriditis. Treatments have been essentially symptomatic but 20% of the children (n=34) required antibiotic therapy. A favourable outcome was observed in all the children. DISCUSSION: Incidence of salmonella infections is increasing in France, particularly in the Languedoc-Roussillon area. Diagnosis of mild forms is generally easy but certain patient background seems to expose to severe forms. Treatment of salmonella infections is mainly symptomatic, only severe or specific cases (young age, immunodepression...) requiring antibiotic treatment. The growing antibiotic use and the increasing of resistance are currently the main problems in the management of salmonella infections. Those infections remain a public health problem in Languedoc-Roussillon.

Adolescent↗
PubMed2005

Impairment in clock-time estimation following right hemisphere ischemic damage.

In order to assess clock-time estimation (CTE), we asked "what time is it in your opinion?" to 48 recent stroke in-patients, 21 with right (RH), 27 with left hemispheric (LH) lesions, and to 20 control in-patients without brain lesions (C). Errors were measured in terms of the number of minutes by which the estimated clock-time was later (advance errors) or earlier (delay errors) than the real clock-time. CTE was considered pathological when exceeding the mean advance or delay errors observed in control patients plus 2.5 standard deviations. The estimation of the duration of a short psychological interview was also assessed. CTE, and not duration estimation, was disturbed in patients. RH patients made significantly more pathological advance errors than LH patients (43% vs. 12%). This study points out the RH dominance for CTE in stroke patients.

Adult↗
PubMed2005

Tactile functions after cerebral hemispherectomy.

Patients that were hemispherectomized due to brain lesions early in life sometimes have remarkably well-preserved tactile functions on their paretic body half. This has been attributed to developmental neuroplasticity. However, the tactile examinations generally have been fairly crude, and subtle deficits may not have been revealed. We investigated monofilament detection and three types of tactile directional sensibility in four hemispherectomized patients and six healthy controls. Patients were examined bilaterally on the face, forearm and lower leg. Normal subjects were examined unilaterally. Following each test of directional sensibility, subjects were asked to rate the intensity of the stimulation. On the nonparetic side, results were almost always in the normal range. On the paretic side, the patients' capacity for monofilament detection was less impaired than their directional sensibility. Despite the disturbed directional sensibility on their paretic side the patients rated tactile sensations evoked by the stimuli, on both their paretic and nonparetic body halves, as more intense than normals. Thus, mechanisms of plasticity seem adequate for tactile detection and intensity coding but not for more complex tactile functions such as directional sensibility. The reason for the high vulnerability of tactile directional sensibility may be that it depends on spatially and temporally precise afferent information processed in a distributed cortical network.

Adult↗
PubMed2003

Nicotine protects rat brain mitochondria against experimental injuries.

Epidemiological studies have reported that cigarette smoking may protect from neurodegenerative diseases such as Parkinson's disease. These protective effects are thought to be mediated by nicotine. Recent data showed that nicotine significantly decreases respiratory control ratio (RCR) and superoxide anion generation of brain mitochondria. Thus, we investigated nicotine effects on rat brain in two experimental models: first, an in vitro anoxia/reoxygenation experiment and secondly, an in vivo rotenone-induced Parkinson-like syndrome. Anoxia/reoxygenation impaired mitochondrial respiration by 43.68% whereas in the presence of nicotine, it was less impaired, by 31.1% at 10(-7) M. In rats chronically administered rotenone (3 mg/kg/day), we observed profound mitochondrial damage: the RCR decreased by 50.36% and the superoxide anion generation and the membrane anisotropy increased by 56.03 and 13.43%, respectively. All of these indications of mitochondrial damage were limited by chronic administration of nicotine. Nicotine developed mitochondrial effects in vivo and in vitro at very low concentration. All these results were in accordance with epidemiological studies, which report a protective effect of nicotine in neurodegenerative diseases. Thus, we propose that one effect of nicotine is to preserve mitochondrial functions of the rat central nervous system.

Animals↗
PubMed2003

[Asomatognosia and oral drive: a psychoanalytical perspective].

OBJECTIVE: The psychoanalytic concept of specular image refers to the complex construction that associates the body image with the language coordinates of the individual, thus making him/her a human subject. The acquisition of this specular image implies the loss of corporeal exchanges between mother and child, i.e., the "neutralization" of those body parts or extensions where these exchanges take place. These conceptions of body image and subjectivity lead to the hypothesis that neurological disturbances of body schema may alter the patients' subjectivity and their relation to the lost "object" insofar as they alter body image. MATERIAL: In the present paper, we present two patients aged under 50, with a unique first ever stroke due to ischemia in the right middle cerebral artery territory and asomatognosia. METHODS: On one hand, Bisiach's protocol was used to assess hemiplegia, sensory troubles, visual troubles, hemineglect and anosognosia, and adapted to assess asomatognosia. On the other hand, subjective data were gathered during a semistructured interview and a self-portrait test. RESULTS: This showed that asomatognosia was accompanied by a destructuration of body image and aberrant oral manifestations involving the paralyzed hand. DISCUSSION-CONCLUSION: The psychological positive phenomena accompanying asomatognosia might correspond to the intrusion of the lost object in the patients' psychic reality, due to the alteration of body schema and body image.

Agnosia↗
PubMed2003

Why is the Plasmodium falciparum hexose transporter a promising new drug target?

Chemotherapy of malaria parasites is limited by established drug resistance and lack of novel treatment options. Intraerythrocytic stages of Plasmodium falciparum, the causative agent of severe malaria, are wholly dependent upon host glucose for energy. A facilitative hexose transporter (PfHT), encoded by a single-copy gene, mediates glucose uptake and is therefore an attractive potential target. The authors first established heterologous expression in Xenopus laevis to allow functional characterisation of PfHT. They then used this expression system to compare the interaction of substrates with PfHT and mammalian Gluts (hexose transporters) and identified important differences between host and parasite transporters. Certain Omethyl derivatives of glucose proved to be particularly useful discriminators between mammalian transporters and PfHT. The authors exploited this selectivity and synthesised an O-3 hexose derivative that potently inhibits PfHT expressed in oocytes. This O-3 derivative (compound 3361) also kills cultured P. falciparum with comparable potency. Compound 3361 acts with reasonable specificity against PfHT orthologues encoded by other parasites such as Plasmodium vivax, Plasmodium yoelii and Plasmodium knowlesi. Multiplication of Plasmodium berghei in a mouse model is also significantly impeded by this compound. These findings validate PfHT as a novel target.

Amino Acid Sequence↗
PubMed2003

Evidence for resveratrol-induced preservation of brain mitochondria functions after hypoxia-reoxygenation.

We have previously shown, as have other authors, that trans-resveratrol (E-resveratrol, 3,4,5-trihydroxy-E-stilbene) reduces reactive oxygen species (ROS) generation of mitochondria freshly isolated from healthy rat brains and that it also counteracts the effect of uncouplers (CCCP) on mitochondrial respiration and oxidative phosphorylation. Two main mechanisms have been shown: firstly, a scavenger effect toward O2- and secondly inhibition of complex III ROS generation. We now report on the effects of resveratrol in a pathological model that mimics the ischemia followed by the reperfusion process which may occur in the human brain. Isolated brain mitochondria were submitted first to hypoxia then to reoxygenation. The aim of this study was to determine the extent of mitochondrial damage induced by this experimental model, to demonstrate which mitochondrial functions were altered and to quantify the extent to which they were prevented by resveratrol. Resveratrol was either added to mitochondria freshly isolated from healthy rat brains or was injected by subcutaneous chronically implanted pumps (0.5, 2 and 10 mg/kg/day for 7 days). The rats were then sacrificed and mitochondria were extracted from brains. To evaluate the respective effects of hypoxia and reoxygenation on mitochondrial functions and the relevant effects of resveratrol, this drug was added (first protocol) either before the complete process (i.e., hypoxia and reoxygenation), or after anoxia before reoxygenation. We found that resveratrol prevented alterations of mitochondrial functions. This substance partly counteracted the decrease in respiratory control and the increase in ROS generation. It fully inhibited the alteration of membrane fluidity and the mitochondrial step of the apoptotic process (evidenced by cytochrome c release and membrane potential collapse). The effects of resveratrol were concentration-dependent (in vitro) or dose-dependent (ex vivo, second protocol). They were not significantly different when the drug was added before or after hypoxia, which suggests that in this model, reoxygenation was the most deleterious process and the stage at which resveratrol was most effective.

Animals↗
PubMed2002

Dehydroepiandrosterone and alpha-estradiol limit the functional alterations of rat brain mitochondria submitted to different experimental stresses.

The effects of dehydroepiandrosterone (DHEA), dehydroepiandrosterone-sulfate (DHEA-S), alpha-estradiol and beta-estradiol on the main functions of purified rat brain mitochondria were investigated in basal conditions and after being submitted to various stresses including anoxia-reoxygenation, uncoupling and apoptosis. In basal conditions, DHEA (1 microM) and alpha-estradiol (1 microM) inhibited the respiratory control ratio (RCR) from 3.1 to 2.3 (25%). After anoxia-reoxygenation, DHEA (1 microM) and alpha-estradiol (1 microM) reversed significantly (P<0.01) the RCR decrease from 1.4 to 2.0 (21.5%) by restoring the state 4. This effect was observed when DHEA was added either before anoxia or before reoxygenation and when alpha-estradiol was added before anoxia. The mitochondrial membranes damaged after the anoxia-reoxygenation were 70 and 50%, respectively, protected by DHEA and alpha-estradiol at 1 microM. They also limited by about 50%, the cytochrome c release induced by the anoxia-reoxygenation. The oxygen consumption of mitochondria in presence of NADH (130 microM) and cytochrome c (5 microM) was significantly inhibited by DHEA and alpha-estradiol with high EC(50) of 30 and 22 pM, respectively. At 1 microM, they also inhibited the 10 microM carbonyl cyanide m-chlorophenylhydrazone-induced uncoupling to about 35% whereas beta-estradiol only decreased it to 9%. Our results indicated that DHEA and alpha-estradiol partly preserved the mitochondrial functions altered by an anoxia-reoxygenation with a concentration-dependent effect. The mechanism involved was independent of the classical genomic effect of steroids, the antioxidant properties but implicated a direct action on the mitochondrial membranes.

Adenosine Triphosphatases↗
PubMed2002

Unmyelinated tactile afferents signal touch and project to insular cortex.

There is dual tactile innervation of the human hairy skin: in addition to fast-conducting myelinated afferent fibers, there is a system of slow-conducting unmyelinated (C) afferents that respond to light touch. In a unique patient lacking large myelinated afferents, we found that activation of C tactile (CT) afferents produced a faint sensation of pleasant touch. Functional magnetic resonance imaging (fMRI) analysis during CT stimulation showed activation of the insular region, but not of somatosensory areas S1 and S2. These findings identify CT as a system for limbic touch that may underlie emotional, hormonal and affiliative responses to caress-like, skin-to-skin contact between individuals.

Adult↗
PubMed2002

Lack of antifertility properties of novel halogenated glycolytic inhibitors and the urinary excretion and metabolism of 1,6-dichloro-1,6-dideoxy-D-fructofuranose in the male rat.

The antifertility action of (R,S)-alpha-chlorohydrin administered orally to male rats was compared with that of several novel chlorinated compounds known to inhibit glycolysis and the kinematics of rat sperm in vitro. Oral gavage of 1,6-dichloro-1,6-dideoxy-D-fructofuranose (dichlorodideoxyfructose, DCF), 1-chloro-3-hydroxypropanone, its dimethylketal and bromopyruvate did not reduce the fertility of male rats below that of controls at the equivalent antifertility dose of (R,S)-alpha-chlorohydrin (5 mg/kg/day) or higher. As anticipated for a compound cleaved to products of (S)-chirality even high doses of DCF (200 mg/kg) showed no effect on renal function. 36Cl-Labelled DCF administered orally to male rats was eliminated only slowly in the urine (16% of the ingested dose excreted in 96 h). In the first 8 h, approximately 50% of DCF was excreted unchanged, 30% was excreted as 3-chlorolactate (BCLA), the oxidation product 3-chlorolactaldehyde and 25% as Cl-. By 24 h little DCF remained and the major metabolite (70%) was BCLA and 20% Cl-. The high rate of dechlorination is most likely responsible for the low antifertility action of DCF.

Acetone↗
PubMed2002

Towards practical soft X-ray spectromicroscopy of biomaterials.

Scanning transmission X-ray microscopy (STXM) is being developed as a new tool to study the surface chemical morphology and biointeractions of candidate biomaterials with emphasis on blood compatible polymers. STXM is a synchrotron based technique which provides quantitative chemical mapping at a spatial resolution of 50 nm. Chemical speciation is provided by the near edge X-ray absorption spectral (NEXAFS) signal. We show that STXM can detect proteins on soft X-ray transparent polymer thin films with monolayer sensitivity. Of great significance is the fact that measurements can be made in situ, i.e. in the presence of an overlayer of the protein solution. The strengths, limitations and future potential of STXM for studies of biomaterials are discussed.

Adsorption↗
PubMed2002

[Chronic eczematiform eruption in the elderly].

INTRODUCTION: Eczematiform eruptions in the elderly represent a relatively frequent motive for consultation and may lead to repeated hospitalization. Their etiologic diagnosis is often difficult and explains the frequent relapses. The frequent relapses can be explained by the difficulty in determining their etiologic diagnosis. The aims of this study were: 1) to specify the evolving characteristics of these eruptions in elderly patients and 2) determine their etiology. PATIENTS AND METHODS: The inclusion criteria in this retrospective study were: patients aged over 65 at the time of diagnosis, presenting with extensive eczematiform eruption (> 20 p. 100 of body surface) and lasting for more than one month. Eczema on stasis dermatitis of the lower limbs and generalized contact eczema were excluded. Eighty-three patients followed between January 1990 and January 1999 were included. The clinical, biological, histological and evolving characteristics were analyzed. RESULTS: Mean age of patients was 77 +/- 8 years and the male female sex ratio was 2.4. Patients received a mean of 4.0 +/- 2.6 drugs/patient, consisting essentially of cardiovascular and psychotropic agents. The cutaneous eruption had evolved a mean of 12.5 months (1 to 48 months) before diagnosis. Eczema was pruriginous in 92 p. 100 of cases. Frequent relapses were observed in 68 p. 100 of cases. Precise etiologic diagnosis was retained in 48 patients (58 p. 100). This was disseminated contact eczema (n=19), lymphoma cutis (n=10), atopic eczema (n=7), scabies acariasis (n=6) and pemphigoid (n=6). No etiologic diagnosis was retained in the remaining 35 patients (42 p. 100). Comparison of the characteristics in the 2 groups showed excessive consummation of medicinal products (p=0.024), predominant eruption of sun-exposed areas (p=0.004) and a greater frequency of histological images of keratinocyte necrosis (p=0.0072) in patients presenting eczematiform eruptions of unknown etiology. DISCUSSION: These observations suggest the eventual responsibility of medicinal products in the occurrence of certain extensive and chronic eczematiform eruptions in the elderly. However, the delays of imputability of various causal drugs were often longer than those currently admitted for toxidermia, and the withdrawal of potentially imputable agents rarely led to spectacular improvement in the lesions. A case test report is in progress to specify this hypothesis.

Aged↗
PubMed2001

In vitro effects of nicotine on mitochondrial respiration and superoxide anion generation.

In this study, we investigated the effects of nicotine on rat brain mitochondria. The polarographic studies determined the effects on the respiratory chain, whereas enzymatic assays and [3H]-nicotine binding allowed us to precisely identify its target and site of action. The measurements of oxygen consumption showed a significantly concentration-dependent inhibition by nicotine (EC50 was 4.95x10(-11) M), and a maximal decrease of 23.90% at 10(-7) M. Nicotine bound to complex I of the respiratory chain and inhibited the NADH-Ubiquinone reductase activity. We also showed that nicotine and NADH were competitive on complex I. Effects of cotinine, the main nicotine metabolite, and nornicotine, were also investigated: nornicotine inhibited the mitochondrial respiration whereas cotinine did not. Because the complex I generates superoxide anion, we investigated the effects of nicotine, following NBT oxidation, and showed that nicotine was able to inhibit this reactive oxygen species (ROS) generation by 15.74% with an EC50 of 2.02x10(-11) M. In conclusion, the present study shows that nicotine interacts with the complex I of brain mitochondrial respiratory chain and decreases ROS generation. This may explain a part of the beneficial and protective effects of nicotine in few neurodegenerative diseases, as suggested by many epidemiological studies.

Adenosine Triphosphatases↗
PubMed2001

[What is a "left"?].

OBJECTIVE: Patients with right hemisphere syndrome may be labeled as "gauche" by the rehabilitation staff. This term corresponds to a variety of oddities in behavior or discourse. The aim of this study is to understand the coherence of these oddities with the classical elements of right hemisphere syndrome. MATERIAL: In this article, we present a detailed study of the discourse and the relation with others of a patient with severe left hemineglect, who was followed up for twelve months and did not exhibited any significant change in his symptomatology. METHODS: This study relies on the data from neuropsychological examination, on notes written after rehabilitation session by the therapists and on data from weekly non-directive interviews. RESULTS: This follow-up revealed disturbances of time sense, reduplication for places, misidentification of therapists, pseudo hallucinations, and showed that the transferential relation was "floating". The non-directive interviews permitted the patient to express his own interpretation of his troubles. He described them in terms of gaps in his body "carapace" and disorganization of the oral drive. CONCLUSION: We propose to consider the symptomatology of this patient in relation with the subjective effects of the breaking up of his body image and the concomitant intrusion of the oral object (in the psychoanalytic sense of this term) in his psychic reality.

Agnosia↗
PubMed2001

The carbohydrate and caloric content of concomitant medications for children with epilepsy on the ketogenic diet.

BACKGROUND: The ketogenic diet for children with refractory epilepsy requires a strict control of the amount of ingested carbohydrates. This can be altered by medication prescribed for the epileptic syndrome or for intercurrent illnesses. The goal of this paper is to compile the carbohydrate and caloric content of commonly used medications in this population. METHODS: We compiled a list of frequently used medications with the help of Canadian manufacturers and the Compendium of Pharmaceuticals and Specialties. We also tested a worst case scenario calculation based on the weight of the tablet. RESULTS: We list the carbohydrate and caloric content of 790 medications studied. Our worst case scenario gives an over-estimate in all cases, making adjustments based on this calculation in an emergency setting safe. CONCLUSION: We propose this list as a tool for physicians, dietitians, nurses and pharmacists. The list can easily be adjusted, based on local practices and reviewed periodically.

Anti-Bacterial Agents↗