Search PubMed⌕ Search

Biomedical subjects

P Allain

Publications and source records attributed to P Allain.

At least 37 records · Page 2Linked to original sources
PubMed2000

[Design of a force sensor to evaluate the grasping movement].

Grasping phenomena are abnormal motor behaviours described after cerebral lesions. They are defined as a stereotyped response, consisting of a progressive forced closure of the patient's hand on the examiner's fingers, when they are slowly moved exerting a strong pressure across the palm in an upward direction. Several types are described. The aim of the study was to develop a force sensor to evaluate the force of grasping in accordance with the force of dragging. The characteristics of this force sensor are presented and the clinical application in two selected patients demonstrated.

Aged↗
PubMed2000

Acute metobromuron poisoning with severe associated methemoglobinemia. Identification of four metabolites in plasma and urine by LC-DAD, LC-ESI-MS, and LC-ESI-MS-MS.

A case of self poisoning with metobromuron, a urea derivative used as a herbicide, is reported. Severe methemoglobinemia observed at the admission (80%) disappeared only at day 11, and hemolysis appeared at day 4 and decreased slowly to day 12. Metobromuron was analyzed by liquid chromatography with diode-array detection. Initial plasma concentration and elimination half-life were 4.9 mg/L and 5 h, respectively. Several metabolites were also detected, and four of those were identified by liquid chromatography-electrospray mass spectrometry. Normetobromuron, bromophenylurea, and bromoacetanilide were detected in plasma, but only N-methyl bromophenylurea was detected in urine. Bromoacetanilide probably results from acetylation of the intermediate bromoaniline. Methemoglobinemia could result from metabolization of metobromuron to bromoaniline and bromoacetanilide.

Acetanilides↗
PubMed2000

Early biotransformations of oxaliplatin after its intravenous administration to cancer patients.

This article deals with the fate of oxaliplatin 1 and 3 h after its i.v. administration (130 mg/m(2)) to three patients. Its binding to plasma proteins and penetration into red blood cells were monitored by chromatography on-line with inductively coupled plasma mass spectrometry. Oxaliplatin biotransformations in plasma ultrafiltrate (PUF) and in urine were studied by chromatography coupled to inductively coupled plasma mass spectrometry or to electrospray ionization mass spectrometry. In plasma, four platinum (Pt) compounds were found. The peaks at 200 and 160 kDa corresponding to gamma-globulins contained 40% of the Pt bound; the peak at 60 kDa corresponding to albumin contained 40% of the Pt found. The peak <2 kDa could correspond to oxaliplatin, to its degradation products, or to adducts between Pt compounds and low-molecular-weight species such as glutathione, L-methionine, and L-cysteine. In PUF and urine, oxaliplatin itself, its degradation products, Pt(dach)Cl(2), [Pt(dach)(OH(2))Cl](+), and species that have the same retention times as Pt(dach)(methionine) and [Pt(dach)](2)(glutathione) were found. One hour after infusion, oxaliplatin in PUF and urine represented 12 and 50% of the total Pt, respectively. Three hours after infusion, oxaliplatin, undetectable in PUF, represented 10% of total Pt in urine. Inside red blood cells, two Pt compounds were found. The Pt peak at 60 kDa corresponding to hemoglobin and the peak <2 kDa corresponding to low-molecular species contained, respectively, 60% and 40% of Pt found. This study demonstrates that in the first hours after its infusion, oxaliplatin, in addition to other Pt compounds, is present in plasma and urine and that Pt is bound to albumin, gamma-globulins, and hemoglobin.

Aged↗
PubMed2000

[Incidence of grasping and its relationship to cerebral lesions].

Grasping is associated with frontal lobe pathology. Nevertheless, there is lack of precise anatomical correlations and very few studies are published. The aim of the study was to determine the incidence of the grasping and its relationship to cerebral lesions. We studied 236 patients admitted to the Neurology Department (108 women and 128 men; mean age 65.3), and tested with a standardized procedure (De Renzi and Barbieri, 1992). A score of grasping was determined for each patient. The locations of the cerebral lesions were assessed by two neurologists using the method of Damasio and Damasio (1989). Grasping was found in 38 patients (16.1p.100) with dementia or cerebral damage. In all cases, the lesion affected the frontal lobe. The patients with grasping showed a significant higher number of lesioned areas particularly for the frontal and the parietal regions. The score of right grasping was significantly higher with a lesion in the right paraventricular frontal and in the left parietal paraventricular areas. The score of left grasping was significantly higher with a lesion in the left frontal paraventricular area. These results are discussed in relationship with motor control.

Age Factors↗
PubMed1999

Fatal poisoning due to intravasation after oral administration of barium sulfate for contrast radiography.

A fatal poisoning after oral administration of barium sulfate for contrast radiography is reported. Barium sulfate is an insoluble salt and therefore is almost nontoxic. The case described here involves a 61-year-old woman who underwent two CT scans of the digestive tract with oral administration of barium sulfate during a surgical procedure. Within several hours after the first barium swallow examination the patient presented nonspecific neurologic and cardiovascular manifestations that rapidly progressed and led to death a few days later. Laboratory findings demonstrated elevated levels of barium in the blood and cerebrospinal fluid. The most likely mechanism of poisoning was progressive intravasation of barium due to stasis of contrast material related to intestinal obstruction.

Acute Disease↗
PubMed1999

Mechanisms of reaction of L-methionine with carboplatin and oxaliplatin in different media: a comparison with cisplatin.

The activity of platinum compounds is dependent on nucleophile substitution reactions. In this paper, we study the reactivity of L-met with carboplatin, oxaliplatin and cisplatin by following with HPLC-UV the concentration of L-met and by characterizing the resulting adducts with LC-MS. In the absence of NaCl, in water, the initial rate at which L-met concentration decreases with cisplatin, oxaliplatin and carboplatin is 0.25 +/- 0.007, 0.057 +/- 0.01 and 0.17 +/- 0.02 mM h(-1), respectively. In phosphate buffer this rate is 0.056 +/- 0.009 for cisplatin, 0.019 +/- 0.001 and 0.13 +/- 0.02 for carboplatin and oxaliplatin, respectively. Reactions of L-met with cisplatin occurred via its conversion into monoaqua species in water and into phosphato-derivatives (AP) in phosphate buffer but finally the same methionine-platinum adducts M2 [(NH3)2(met)]Pt, M4 and M5 [(met)2]Pt were characterized. Reaction of carboplatin with L-met occurred via the formation of M0 [(NH3)2(met)(CBDCA)]Pt whose structure is consistent with the direct interaction of L-met with carboplatin. However, the same final products as those found with cisplatin were characterized. The reaction of oxaliplatin with L-met proceeded through a mechanism similar to that of carboplatin to give M7 [(met)(DACH)]Pt. In the presence of NaCl, cisplatin directly reacted with L-met to yield at least five methionine-platinum adducts. The reaction of carboplatin gave the same adducts suggesting its transformation into cisplatin. The reaction of oxaliplatin with L-met occurred via the formation of aquated species A [(OH)(Cl)(DACH)]Pt which readily underwent reaction with L-met to form M6 [(met)(Cl)(DACH)]Pt and M7. This study shows that the reactivity of cisplatin, carboplatin and oxaliplatin is dependent on the media in which they occur. The discrepancy between their reactions with L-met could partly explain their therapeutic differences.

Antineoplastic Agents↗
PubMed1999

Manganese transport by Caco-2 cells.

The uptake and transport kinetics of manganese (Mn) were investigated in the human intestinal Caco-2 cell line both from the absorption side (apical to basolateral) and from the exsorption side (basolateral to apical). With regard to the former, transport versus time revealed (as uptake) a biphasic pattern with an initial transient phase followed by steady-state conditions. Uptake versus Mn concentrations showed saturation-type kinetics with a 100% increase of Mn binding capacity when measurements were made from 0.5 to 2 h of incubation. The transport characteristics in steady-state conditions exhibited two components, saturable (Vmax = 3.70+/-0.07 nmol/cm2/h, K(m) = 32.2+/-3.4 microM) and nonsaturable (slope = [1.4+/-0.2] x 10(-6)cm(-2)/h) usually presumed to reflect transcellular (carrier mediated) and paracellular (diffusional) pathways, respectively. Mn fluxes were decreased by calcium and calcium antagonists, almost 100% inhibited at 4 degrees C, and affected by quinacrine and ouabain. The inhibition of ATP synthesis was apparently ineffective. From the exsorption side, the Mn fluxes, without a transient period, had an approx 20-fold smaller rate than in the absorptive direction and showed mainly a nonsaturable route (slope = [0.6+/-0.1] x 10(-6) cm(-2)/h). The mechanisms participating in the Mn movements through the monolayer are discussed and proposed to be in common, at least partly, with other divalent cations such as calcium, zinc, or iron.

Biological Transport↗
PubMed1999

[Barium sulfate poisoning?].

We report a case with neurologic symptoms which occurred after iterative radiologic examinations of the gastrointestinal tract with barium sulphate, which were related to a barium encephalopathy. Suspected by the presence of barium in the blood, a systematic intoxication was occurred without any evidence for a gut or a vascular leak. This case raises the question about a possible extraluminal diffusion of such a heavy metal, given orally, in normal conditions of use.

Barium Sulfate↗
PubMed1999

Mental representation of knowledge following frontal-lobe lesion: dissociations on tasks using scripts.

Twenty-three frontal-brain-damaged subjects, 10 posterior-brain-damaged subjects and 10 normal controls were compared on script tasks. They were first asked to re-establish the sequential and hierarchical structure of 2 script actions, and then, they were asked to order 2 new scripts which contained aberrant items. Impairments in script information processing were observed only in frontal patients. Of the 23 frontal patient tested 8 made errors in ordering actions, in choosing scenes and in making estimates of action importance in the first task, and they rejected the aberrant elements in the second task. Eleven frontal subjects performed as well as the control subjects in the first task, but used the irrelevant items. The last 4 frontal patients performed as well as the control subjects in both tasks. These results support a possible fractionation of the frontal lobe syndrome.

Adult↗
PubMed1999

[Plasma homocysteine is not a predictive factor of restenosis after coronary angioplasty].

Hyper-homocysteinaemia is a cardiovascular risk factor. In parallel, anatomopathological studies of post-angioplasty coronary restenosis show histological appearances similar to those observed in patients with severe hyper-homocysteinaemia. Based on these histological observations, the authors tried to assess the predictive value of raised plasma homocysteine levels for coronary restenosis after angioplasty. Two hundred and twenty-two patients treated by coronary angioplasty were followed up clinically for 6 months. Thallium 201 myocardial scintigraphy was performed in 179 patients and coronary angiography in 74 patients. Seventy-nine patients had coronary restenosis diagnosed by coronary angiography in 55 cases, by myocardial scintigraphy in 23 cases and strongly suspected clinically in only one patient. No significant differences in homocysteine levels were observed between patients with multiple restenosis or requiring revascularisation, and those without restenosis and not requiring revascularisation. Plasma homocysteine does not therefore seem to be a predictive factor of post-angioplasty coronary restenosis.

Aged↗
PubMed1998

[Lead blood levels in children under 6 years of age in the Mans region].

OBJECTIVES: High lead levels in children can have a deleterious effect on intellectual development. We assessed blood lead levels in children in the Le Mans region. METHODS: Children aged between 6 months and 6 years were included in the study. Inclusion criteria were health status requiring a blood sample and amount of blood available after ordered tests sufficient for lead blood analysis. The study group included 365 children. RESULTS: Mean blood level in the 365 children was 37.2 +/- 20.6 micrograms/l. Six of the children had blood levels greater than 100 mu/l. None of the children had a level over 200 micrograms/l. Location of the home or date of construction of the home were not significantly correlated to blood lead levels, however blood lead levels were higher in children with neurological or behavioral disorders. This observation was made in a limited number of children. CONCLUSION: The risk of excessively high blood lead levels in children under 6 years of age is low in the Le Mans region. There is however a risk when old houses are renovated or in children with neurological or behavior disorders.

Age Factors↗
PubMed1998

Study of haemostasis in depressive patients treated with fluoxetine.

The object of this study was to investigate a possible pharmacological effect of fluoxetine on haemostatic function, with special attention on primary haemostasis, in order to explain haemorrhagic complications reported in some treated, depressed patients. The haemostatic function of depressive patients, who required fluoxetine therapy, was studied before and after 1 month of treatment with fluoxetine 20 or 40 mg daily. Exclusion criteria were: pregnancy, initial abnormal haemostatic function, history of coagulation abnormalities, treatment with drugs that interfere with haemostasis, and recent fluoxetine therapy. The following tests were performed: prothrombin time, partial thromboplastin time, thrombin time, plasma fibrinogen, platelet counts, bleeding time, platelet aggregation induced by ADP, epinephrine, ristocetin, collagen, arachidonic acid, and plasma determination of fluoxetine and norfluoxetine levels. Statistical analysis was performed by Wilcoxon paired sample, one-tailed test (alpha=0.05). Among 18 patients included, only eight completed the trial. The single statistically significant difference was a decreased velocity in platelet aggregation induced by epinephrine without increased bleeding time. The results failed to demonstrate any compromised haemostatic function after 20 mg daily fluoxetine therapy in patients with initial haemostatic function. However, the results suggest possible effects of fluoxetine on platelet adrenoreceptors.

Journal Article↗
PubMed1998

Benzene exposure in car mechanics and road tanker drivers.

The purpose of this study was to identify professional factors related to benzene exposure and to deduce suitable safety measures. Atmospheric benzene, urinary muconic acid (tt-MA) and leukocyte alkaline phosphatase activity (LAPA) were evaluated among 66 car mechanics, 34 road tanker drivers, and 28 nonexposed workers. Professional and medical questionnaires were filled in at the same time. Atmospheric benzene was significantly higher among road tanker drivers than among car mechanics. The arithmetic mean +/- SD, median, and geometric mean values were, respectively, 0.48 +/- 1.49, 0.14, and 0.06 mg/m3 among car mechanics and 1.88 +/- 4.18, 0.68, and 0.65 mg/m3 among road tanker drivers. In the latter case the increase was caused by transport of unleaded petrol and correlated with the volume of the tank. Among car mechanics, tobacco smoking, windy conditions, dismantling of petrol filters, and handling of petrol increased atmospheric benzene levels. Urinary muconic acid was increased significantly among car mechanics (148 +/- 137, 127, and 111 micrograms/g) and among road tanker drivers (309 +/- 420, 137, and 151 micrograms/g) as compared with the controls (49 +/- 46, 33, and 33 micrograms/g). Among road tanker drivers, alcohol intake and transportation of unleaded petrol increased the excretion of muconic acid, which was also directly related to the volume of the tank. Among car mechanics, professional factors (dismantling of petrol filters, handling of and washing of hands with petrol) and nonprofessional factors (tobacco smoking and damaged skin on the hands and forearms) increased muconic acid excretion. In the control group, tobacco smoking increased its excretion. LAPA was not significantly modified among exposed workers. There was a weak but significant linear correlation between LAPA and muconic acid. These results suggest that to reduce exposure to benzene in unleaded petrol, individual and collective safety measures should be imposed in both occupations.

Air Pollutants, Occupational↗
PubMed1998

Cognitive functions in chronic locked-in syndrome: a report of two cases.

We describe a 38-year-old woman and a 38-year-old man who have been living in a "locked-in" condition 3 and 2 years, respectively. Extensive neuropsychological testing, carried out with a communication aid system (writing apparatus) which exploited the patients residual eye movements, showed preserved cognitive abilities in spite of the long standing de-efferentation.

Adult↗
PubMed1998

Determination of unbound platinum after oxaliplatin administration: comparison of currently available methods and influence of various parameters.

Variations in plasma protein binding may have profound effects on both disposition and activity of drugs, especially for those which are tightly bound to proteins, such as anticancer platinum derivatives. Methods of separation of the non-protein-bound fraction and some technical parameters may influence the results. We have compared ultrafiltration and ultracentrifugation, as well as the effect of potentially interfering factors, upon the determination of the plasma unbound platinum fraction after oxaliplatin administration to cancer patients. Ultrafiltration and ultracentrifugation provided very closely correlated results, so that either technique can be used. The ultrafiltration cut-off (3000-30,000 Da) devices, the type of tube for blood sampling and the type of anticoagulant (none, lithium heparinate or EDTA) did not influence the results markedly. In contrast, results were greatly influenced by freezing: erratic results were obtained on thawed plasmas when compared with those on fresh serum or plasma. Consequences may be important in usual practice, since many pharmacokinetic studies are carried out in multicentric trials with plasma processing centralized in one reference laboratory. The methods for the determination of protein-drug binding should be standardized and guidelines elaborated where optimal conditions for each type of binding assay are given.

Antineoplastic Agents↗
PubMed1998

[Plasma noradrenaline and the prognosis of chronic cardiac failure: a multicenter study].

Plasma noradrenaline is little used in evaluating the prognosis of cardiac failure because of the theoretical necessity of interrupting treatment for a few days before blood sampling. The present study reevaluated the prognostic value of this parameter with blood sampling performed during treatment and then 48 hours after withdrawal of treatment in 192 patients with chronic stable cardiac failure at an advanced stage (64% of patients in Classes III or IV with an average ejection fraction of 28.5 +/- 13.5%). During follow-up (average 43 months) there were 51 deaths and 17 transplants. None of the patients were lost to follow-up. Univariate analysis of 52 variable observers during the initial phase of evaluation found in decreasing order of predictive value for death plasma noradrenaline levels before and after withdrawal of treatment for 48 hours. Serum sodium, age, systolic mean and diastolic pulmonary artery pressures. In multivariate analysis: noradrenaline with or without withdrawal of treatment, hyponatraemia and systolic pulmonary artery pressure. Actuarial survival curves distinguished the following parameters: noradrenaline levels became predictive at concentrations of over 210 pg/mL and there was a significant difference in survival with respect to 4 levels of serum noradrenaline (with or without treatment) > 300 pg/mL, 300 to 600 pg/mL and > 900 pg/mL. This serum noradrenaline measured without withdrawal of treatment (especially angiotensin converting enzyme inhibitors) is a powerful predictor of mortality, carrying a progressively poorer prognosis as the concentration increases.

Adult↗
PubMed1997

[Lead impregnation in inhabitants of the Rabat region (Morocco)].

OBJECTIVES: No current data is available on plumbism in Morocco. We conducted this work to evaluate blood lead levels in inhabitants of the Rabat region. PATIENTS AND METHODS: The study included 385 subjects, 300 men and 85 women, age range 18-55 years, who were volunteer blood donors at the Rabat blood bank. All subjects responded to a short questionnaire concerning type of lodging cigarette smoking, occupation. Blood lead levels were assayed by inductively coupled plasma-mass spectrometry (ICPMS). RESULTS: Mean blood lead levels for all subjects was 86.9 +/- 42.1 micrograms/l (92.9 +/- 51.7 micrograms/l for men and 80.9 +/- 32.6 micrograms/l for women). Blood lead levels increased more rapidly with age in women than in men. Levels in subjects who lived in residential urban areas were lower than those living in the old Arab center. Levels were higher in smokers than in non-smokers and in subjects with an employment than in those without. CONCLUSION: Mean blood lead levels in the Rabat region are similar to those currently observed in other countries where this same type of study has been conducted. Similar factors are associated with high mean blood lead levels.

Adolescent↗