Search PubMed⌕ Search

Biomedical subjects

H Robert

Publications and source records attributed to H Robert.

At least 37 records · Page 2Linked to original sources
PubMed1999

Phase-modulated rotating-frame NQR techniques for spatial encoding

The rotating-frame method of localization for spatially resolved spectroscopy and imaging in the pure quadrupole regime relies on a gradient B(1) field in which spins experience a flip angle dependent on their position in the B(1) field strength. So far, the techniques have been implemented as amplitude-modulated methods, i.e., the spatial nuclear quadrupole distribution is encoded in the amplitude of the free-induction decay signals. In this work, we describe the implementation of phase-modulated variants of both two-dimensional and rapid rotating-frame imaging techniques. The experiments are discussed for both single crystalline and powder samples. The phase-modulated experiment offers some advantages over the amplitude-encoding technique: It enables one to distinguish the sign of the spatial coordinate and the signal-to-noise ratio is higher than for the simplest amplitude-encoding method. Copyright 1999 Academic Press.

Journal Article↗
PubMed1999

Iron deficiency in older people: interactions between food and nutrient intakes with biochemical measures of iron; further analysis of the National Diet and Nutrition Survey of people aged 65 years and over.

OBJECTIVE: To quantitatively investigate relationships between food consumption, nutrient intake and biochemical markers of iron status in a population of older people. DESIGN: National Diet and Nutrition Survey: cross-sectional survey of a nationally representative population of men and women aged 65 y and over. SETTING: Mainland Great Britain SUBJECTS: 1268 participants (651 men and 617 women) who provided both dietary intake and blood biochemistry. 986 were living in private households and 282 were living in residential or nursing homes. RESULTS: Intakes of alcohol, vitamin C, protein, haem and non-haem iron and fibre were positively associated with iron status. Consumption of meat, poultry and fish were positively associated with six measures of iron status, and vegetables and potatoes with four measures. Calcium, dairy foods and tea generally had a negative association with most measures of iron status. CONCLUSIONS: A varied diet containing meat, poultry and fish, vegetables and fruit, with a moderate intake of alcohol will make a positive contribution to the iron status of elderly people.

Aged↗
PubMed1999

Clozapine-olanzapine: a potentially dangerous switch. A report of two cases.

BACKGROUND: Withdrawal symptoms associated with switch between two typical antipsychotics are generally rare and mild. In contrast, switching from clozapine to risperidone can be lead to severe withdrawal symptoms. Different pathophysiologic aetiologies have been suggested for explaining these severe symptoms, including cholinergic supersensitivity and rebound. Theoretically, the switch from clozapine to olanzapine should not lead to any problems because those two agents have the same affinity in vitro for muscarinic receptors. OBJECTIVE: This study reports two cases of switches from clozapine to olanzapine, in refractory schizophrenic patients, which were associated with severe withdrawal symptoms. RESULTS: After the switch, the two patients developed diaphoresis, hypersialorrhea, bronchial obstruction, agitation, anxiety and enuresis. The symptoms were treated with anticholinergic medication and by an increase in dose of olanzapine to 20 mg/day. For one of the patients this treatment led to normalization of secretion. For the other patient, a superinfection leading to a bilateral pneumopathy which required emergency hospitalization in a general hospital was observed. CONCLUSION: The symptomatology and the response to treatment lead to the hypothesis of a muscarinic from abrupt weaning. The withdrawal symptoms disappeared rapidly with an increase in olanzapine dosage and with anticholinergic started at the beginning of the switch. We recommend slow clozapine weaning over 3 weeks or more with concurrent anticholinergic treatment.

Adult↗
PubMed1999

Autologous chondrocyte implantation. A review of techniques and preliminary results.

The treatment of deep focal bone and cartilage defects in weight-bearing areas of the knee remains challenging. Autologous chondrocyte implantation is a recently introduced alternative to drilling and mosaicplasty and is gaining ground in France under the impetus of favorable results obtained in other countries in highly selected cases. The technique and preliminary results are discussed herein.

Cartilage, Articular↗
PubMed1998

Mapping molecular orientation in solids by rotating-frame NQR techniques

A multi-dimensional NQR technique to image both the spatial distribution of quadrupolar nuclei and the local orientation of the electric field gradient tensor at the quadrupole sites in solids is reported. The encoding procedure is based on the irradiation of the sample by a pulse sequence composed of spatially homogeneous and inhomogeneous radiofrequency fields. A method that encodes the spatial and orientation information in the amplitudes of the free-induction decay signals and a proper three-dimensional reconstruction procedure that yields the space-orientation-dependent NQR spectra are described. A two-dimensional variant allows rapid measurement of the spatially dependent orientation distribution of molecules, disregarding the spectroscopic information. Copyright 1998 Academic Press.

Journal Article↗
PubMed1997

[Medico-economic evaluation of treatment with clozapine versus treatment with previous neuroleptics].

Since clozapine has been introduced into the treatment of schizophrenia, pharmaceutical costs rised in hospital. However, this data is not sufficient to estimate its global effect on cost-effectiveness; that's why we studied the whole direct costs generated by schizophrenia, the clinical effectiveness as well as the impact of therapeutics on the patients' quality of life. This work is a retrospective study of cost-effectiveness of clozapine treatment within three french psychiatric hospitals. The study was divided into three parts: - a twelve-month period concerning the treatment before clozapine; - two twelve-month periods for the analysis of clozapine treatment. The clinical evaluation was based on the CGI and an autoevaluation scale. Whether schizophrenic patients were hospitalized or not and the importance of neuroleptic-associated medicines were taken into account to evaluate the Quality of Life. The economical assessment is represented by adding pharmaceutical costs, biological examinations costs and hospitalization costs. Thirty-seven patients, out of seventy-five, were being taken into account (26 men and 11 women). The results of the CGI and autoevaluation scale showed a global improvement in the pathology within the first year of treatment, which is confirmed during the second year. A statistically significant decrease in the length of full-time hospitalization was noticed; this profits to half-time hospitalization, indeed purely ambulatory. The direct costs per patient and per day insignificantly decreased between the first and the second period; on the other hand, the drop was statistically significant between the second and the third period. This study, based on a small amount of patients shows that the use of clozapine, which clearly helped the patients to improve, leads to a drop in global direct costs per patient, despite the high cost of the medicine itself, as well as an improvement in the quality of life.

Adult↗
PubMed1997

[Focal myositis in children. Apropos of a case].

An eleven year old boy presented with localized swelling of the left calf which had been developing for more than 5 years. Another smaller mass was found in the pretibial area. There was an invincible equinus deformity of the foot. Surgical biopsies revealed characteristic histological features of focal myositis showing necrotic and regenerating muscle fibers, randomly distributed, with inflammatory infiltration. An intense fibrotic reaction was observed. This constitutes to our knowledge the first reported case of focal myositis in which development of muscle sclerosis was so important that it was necessary to perform tenotomies one year after excision of the principal tumor in order to restore normal gait. A nearly two-years follow-up does not give evidence of recurrent lesion.

Achilles Tendon↗
PubMed1996

Determination of clozapine in serum by radioreceptor assay versus high-performance liquid chromatography: possible detection of hydroxy-metabolites.

Clozapine is an antipsychotic drug with few extra-pyramidal motor side-effects, used to treat schizophrenia which is resistant to classical neuroleptic therapy. This report shows that norclozapine but not clozapine-N-oxide has the same D2 receptor affinity as clozapine. Assay results suggest a bimodal distribution which may be explained by CYP1A2 polymorphism. Extensive metabolizers could produce other active metabolites, probably other hydroxy-clozapine derivatives.

Animals↗
PubMed1992

[Electrophysiologic data on myasthenic syndromes of the Lambert-Eaton type. A series of 23 cases].

The electrophysiological data of 23 adult patients with Lambert-Eaton myasthenic syndrome (LEMS) have been reviewed. Lung carcinoma was disclosed in 17. In six cases with an EMG follow-up ranging between one and 17 years no carcinoma was detected. The results of repetitive nerve stimulation test (RNS) were not statistically different between the 2 groups. Low CMAP ulnar amplitude was present in all patients (mean: 1.7 mV). Decremental response at low rate of stimulation (3 Hz) was present in 17/20 (means: 30%). An abnormal incremental response at high rate of stimulation was present in all cases (mean: 826%). The authors emphasize the interest of a 50 Hz stimulation for 4 s. Increase of the 'F-wave' amplitude was noticed in some cases. Electrophysiological changes suggestive of an associated mild neuropathy were noticed in eight patients but H-reflex was present in 3/3 cases. SFEMG abnormalities were found in 6/6 cases. In one case, stimulated SFEMG showed more blockings and an increased jitter with low rate of stimulation. In one case the electrical pattern of RNS could be misinterpreted as myasthenia gravis in one tested muscle only. The author's results suggest that CMAP amplitude and RNS test could be used to appreciate the short-term improvement of LEMS with treatment and in some cases for the long-term follow-up.

Adult↗
PubMed1990

A new series of antiarrhythmic procainamide derivatives: toxicity and activity-simulated passive absorption relation.

Several compounds derived from benzamidines and nicotinic pyridinic amidines with a structure similar to that of procainamide, exhibit notable antiarrhythmic properties after injection into animals. The diffusion rate of these different compounds through a solid lipidic artificial membrane was studied with Dibbern's apparatus. A statistical relation was established between the diffusion rate and the principal pharmacological parameters obtained after intraperitoneal injection (toxicity and anthiarrhythmic activity). Essential structural elements seem to determine a better bioavailability than procainamide: character of the substitution (in para) of the benzenic cycle; length of the lateral chain.

Absorption↗
PubMed1987

Histiocytosis X in the juvenile spine.

The authors studied 54 lesions, caused by histiocytosis X, that affected the spines of 28 children. The clinical, radiologic, biologic, and therapeutic aspects are described. The orthopaedic surgeon has a role to play in confirming the diagnosis, treating the lesion, and in following up.

Adolescent↗
PubMed1986

Histological study of a polyamide arterial allograft (inside diameter: 1.5 mm) in rats.

The histological results of the implantation of twenty aortal prosthesis (6-6 polyamide, internal diameter 1.5 mm) in rats are presented. The success rate is 77%. Biological tolerance is remarkably good. After the first month, the formation of a continuous endothelial layer is noted. At three months, the structure of the neo-membrane resembles that of the aortal.

Animals↗
PubMed1983

Study of the water--collagen system by NMR cross relaxation experiments.

The present work is a study of cross relaxation between water and collagen by NMR pulse techniques. This cross relaxation experiment is easy to set up for NMR spectrometers and gives further information supplementary to other experiments. Relaxation parameters derived from this method provide a sensitive means of monitoring the hydration-dependent behaviour of different types of collagen.

Chemical Phenomena↗
PubMed1983

[Utilization behavior during the course of progressive multifocal leukoencephalopathy].

A particular semiologic feature of a case of progressive multifocal leukoencephalopathy was the existence of utilization behavior as described by Lhermitte. The affection developed in a patient with myeloid leukemia treated by cytotoxic drugs. Multifocal low density areas were shown by CT Scan examination. The course of the disease was not altered by isoprinozine therapy.

Adult↗