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Biomedical subjects

A Richard

Publications and source records attributed to A Richard.

At least 37 records · Page 2Linked to original sources
PubMed2001

Diet profiles in a population sample from Mediterranean southern France.

OBJECTIVE: A Mediterranean diet quality index (MDQI) was devised to give an overall assessment of dietary habits and to identify groups at risk. DESIGN: The MDQI was based on scores given for selected levels of consumption of selected nutrients and foods. SETTING: Mediterranean southern France. SUBJECTS: The sample included 473 men and 491 women in three age classes recruited at random. RESULTS: Only 9.5% of men, 9.0% of women, 4.7% of 20-34 year old subjects, 6.6% of 35-54 year old subjects and 14.0% of 55-76 year old subjects were shown to have a healthy diet. However, 10.1% of men, 8.6% of women, 19.4% of 20-34 year old subjects, 10.2% of 35-54 year old subjects and 4.6% of 55-76 year old subjects were shown to have a poor diet. There were significantly fewer smokers among subjects with a good diet but the distribution of moderate wine drinkers was comparable between those with a good diet and those with a poor diet. Correspondence analysis associated a healthy diet with 55-76 year old men and women living in rural areas, who had received primary schooling only and who were manual workers. Both men and women with a poor MDQI score tended to be young and smokers. In addition, women with a poor MDQI tended to be heavy drinkers and obese. CONCLUSIONS: This study showed that the Mediterranean model, which is generally recognized as a healthy diet, appears restricted to older people and to rural areas, whereas urbanized young people depart from it. A nutritional prevention policy targeted at young adults is required to encourage them to adhere to the Mediterranean model. Smoking and drinking showed different distribution patterns in the sample under study.

Adult↗
PubMed2001

Poly(glutamic acid) for biomedical applications.

Paclitaxel is a widely used anti-cancer agent. Conjugates of paclitaxel with poly(glutamic acid) have shown great promise in preclinical trials, and clinical trials are now underway. Preclinical data suggest that more paclitaxel is preferentially delivered to tumor sites vs. nonconjugated paclitaxel. When poly(glutamic acid) is conjugated to other families of cancer drugs, similar improvements in effectiveness and reduced toxicity are observed. Optimization of poly(glutamic acid) for use in drug delivery applications is a key step in making this technology viable.

Drug Delivery Systems↗
PubMed2001

[CagA status and virulence of Helicobacter pylori strains. Results of a French multicentric prospective study].

UNLABELLED: Previous experimental and epidemiological studies with few patients suggested that the presence of the cagA gene was a virulence factor for Helicobacter pylori (H. pylori). AIM: To establish in this large epidemiological cohort study the relationship between the histological virulence of H. pylori infection and the cagA status of the bacteria. METHODS: This prospective cohort study (6 month follow-up) was conducted on adult patients undergoing endoscopy for upper gastrointestinal symptoms. The cagA status of H. pylori-positive patients was established using the polymerase chain reaction (PCR) method on an antral biopsy. A score of histological virulence (inflammation, activity) was recorded on the basis of the Sydney system (on antral, angular and fundic biopsies). Eradication treatment given was not imposed and a clinical follow-up was performed at 3 and 6 months. H. pylori eradication was verified by a 13C urea breath test at 3 months. RESULTS: Four hundred and twenty two centers recruited 652 patients (mean age: 51 +/- 15 years, 55% female). Upper GI endoscopy was abnormal in 80% of the patients of whom 68% had a gastritis aspect; 38% were infected by H. pylori, and among them 51% were cagA-positive. The histological virulence scores associated with the cagA-positive strains were significantly higher than those associated with the cagA-negative strains, globally (P = 0.0035), in the antrum (P = 0.0063), and in the angulus (P = 0.046), but not in the fundus (P = 0.05). The cagA status was correlated neither with the symptom severity at inclusion and at 6 months (P > 0.05), nor with the H. pylori eradication rate at 3 months (75% in cagA-positive and 70% in cagA-negative strains, P = 0.52). CONCLUSION: This study on a large cohort of patients confirms the greater histological virulence of H. pylori cagA-positive strains. However, this virulence was not associated with more severe symptoms nor with an increase in resistance to H. pylori eradication treatment.

Adult↗
PubMed2000

Parietal and cingulate processes in central pain. A combined positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) study of an unusual case.

Parietal, insular and anterior cingulate cortices are involved in the processing of noxious inputs and genesis of pain sensation. Parietal lesions may generate central pain by mechanisms generally assumed to involve the 'medial' pain system (i.e. medial thalamic nuclei and anterior cingulate cortex (ACC)). We report here PET and fMRI data in a patient who developed central pain and allodynia in her left side after a bifocal infarct involving both the right parietal cortex (SI and SII) and the right ACC (Brodmann areas 24 and 32), thus questioning the schematic representation of cortical pain processing. No rCBF increase was found in any part of the residual cingulate cortices, neither in the basal state (which included spontaneous pain and extended hypoperfusion around the infarct), nor during left allodynic pain. Thus, as previously observed in patients with lateral medullary infarct, neither spontaneous pain nor allodynia reproduce the cingulate activation observed after noxious pain in normal subjects. Conversely, both PET and fMRI data argue in favour of plastic changes in the 'lateral discriminative' pain system. Particularly, allodynia was associated with increased activity anteriorly to the infarct in the right insula/SII cortex. This response is likely to be responsible for the strange and very unpleasant allodynic sensation elicited on the left side by a non-noxious stimulation.

Brain Mapping↗
PubMed2000

[Mothers' behavior regarding infant sleep position: effects of the last public campaign to prevent sudden infant death syndrome].

BACKGROUND: To define infant care practices in maternity units and those subsequently adopted at home. Using these data, we evaluated the acceptance and application of recommendations issued by the previous public education campaign on infant sleeping position as related to sudden infant death syndrome. PATIENTS AND METHODS: A survey was carried out in two maternity units (Port-Royal and Créteil) and in one pediatric consultation unit (affiliated with Port-Royal maternity). RESULTS: The mixed position (side or back) is used equally with, respectively, 47% at Port-Royal and 45% at Créteil. The supine sleeping position (French public health recommendations) is used by 12% of the mothers at Port-Royal and by 40% at Créteil. It appears that hospital nurseries play an important role in determining the mother's preference for the sleeping position (64% at Port-Royal and 54% at Créteil), but it does not adequately explain all mothers' responses. However, as the infants mature (> two months old), the more spontaneously they changed their sleeping position. All the infants placed in a side sleeping position moved to a supine sleeping position during the night. Upon awakening, infants were found mostly in the supine position (in contrast to the national public education campaign). CONCLUSION: Our results show that mothers and hospital nurseries were distressed in terms of ensuring the supine sleeping position of the infant. New choices of sleeping positions were initiated by mothers. For example, they used the side position after feedings essentially in the case of reflux or during the daytime. The supine position was used when the mothers were assured that any problems had been avoided or only during the night.

Adult↗
PubMed2000

The practice of structure activity relationships (SAR) in toxicology.

Both qualitative and quantitative modeling methods relating chemical structure to biological activity, called structure-activity relationship analyses or SAR, are applied to the prediction and characterization of chemical toxicity. This minireview will discuss some generic issues and modeling approaches that are tailored to problems in toxicology. Different approaches to, and some facets and limitations of the practice and science of, SAR as they pertain to current toxicology analyses, and the basic elements of SAR and SAR-model development and prediction systems are discussed. Other topics include application of 3-D SAR to understanding of the propensity of chemicals to cause endocrine disruption, and the use of models to analyze biological activity of metal ions in toxicology. An example of integration of knowledge pertaining to mechanisms into an expert system for prediction of skin sensitization to chemicals is also discussed. This minireview will consider the utility of modeling approaches as one component for better integration of physicochemical and biological properties into risk assessment, and also consider the potential for both environmental and human health effects of chemicals and their interactions.

Animals↗
PubMed2000

Epidemiology of recurrences or reinfections of Clostridium difficile-associated diarrhea.

Approximately 15 to 35% of patients with a first episode of Clostridium difficile-associated diarrhea relapse within 2 months. Between 1994 and 1997, strains from 93 hospitalized patients with C. difficile recurrences were fingerprinted by using both serotyping and PCR-ribotyping. The results showed that 48.4% of clinical recurrences were, in fact, reinfections with a different strain of C. difficile. Rates of clinical recurrences could therefore be reduced by implementing strict isolation precautions.

Adolescent↗
PubMed2000

[Multidisciplinary treatment of neurologic pain and indications for antalgic surgery].

We present our multidisciplinary approach systematically adopted for patients with resistant pain. All the anatomic, pathophysiological, clinical, radiographical, electrophysiological and psychological aspects of pain should be considered before deciding on treatment indication. These principles are illustrated by a description of different available medical and surgical techniques for the treatment of paraplegic pain. We emphasize the importance of pain centers in caring for these patients. All possibilities for antalgic treatment can be considered in such centers, providing a better approach to all aspects of pain.

Humans↗
PubMed1999

Sebum rheology evaluated by two methods in vivo. Split-face study of the effect of a cosmetic formulation.

Modulation of the rheological characteristics of sebum at the surface of the skin might represent a valuable strategy for the treatment of seborrhea. In this field, only a small number of studies have addressed sebum diffusion within the stratum corneum. In an open, split-face study conducted on 20 men, we measured the sebosuppressive effect of Effidrate cream which is based on a glycerol alkyl-ether. Measurements were made in the morning at three-week intervals for a total period of 3 months. Sebum casual levels and sebum excretion rates were measured using a SM810 Sebumeter. Lipid-absorbent Sebutape was also used to collect all the sebum released from infundibular reservoirs over a four-hour period. Clinical assessments were relatively uninformative but the photometric measurements showed that Effidrate cream had a sebosuppressive action. The underlying biological mechanism remains unclear but a hypothesis based on enhanced sebum absorption by the stratum corneum is discussed.

Administration, Cutaneous↗
PubMed1999

[Epidemiology of gastro-esophageal-reflux in general practice. . Predictive factors for health care utilization in the course of a year].

AIM: To assess the epidemiology and course of GORD, treatment demand, and factors predictive of GORD course in a 1-year study in patients with heartburn consulting general practitioners. METHODS: A total of 984 patients with pyrosis were included by general practitioners. After the initial visit, they had follow up at 3, 6 and 12 months by phone contact. RESULTS: Most patients (87%) had been suffering from heartburn for 4+/-1.5 years; upper GI endoscopy had been performed in 63% of patients. Patients evaluated the symptoms of the current episode as mild (6%), moderate (60%), or severe/incapacitating (34%). During the year of follow up, 12% of the patients were free of heartburn; the mean number of consultations with general practitioners and gastroenterologists was 5.1 and 0.5 respectively. At day 90, discomfort due to heartburn was absent in 4% of patients, slight in 51%, moderate in 32%, and severe in 6%. At day 360, predictive factors for discomfort were: discomfort related to heartburn on D90, the length of time the patients had been suffering from GORD, and the main reason for consultation on D1; patients for whom heartburn was not the main reason for consultation on D1 experienced a higher level of discomfort. The predictive factors for the extent of treatment demand over 12 months were: age, discomfort related to heartburn on D90, severity on D1, the frequency of episodes prior to the episode on D1 and the levels of stress and anxiety measured on D1. CONCLUSIONS: Epidemiologic characteristics of patients with heartburn consulting a general practitioner were different from these of the general population. Treatment demand depends both on severity of heartburn and level of stress and anxiety.

Adult↗
PubMed1998

Efficacy of protective creams in a modified repeated irritation test. Methodological aspects.

The effect of 3 protective creams and petrolatum was tested in a repetitive irritation test. On 15 healthy volunteers, the irritants (sodium lauryl sulfate 10%, sodium hydroxide 0.5%, lactic acid 15%, and toluene undiluted) were applied on the paravertebral skin of the mid-back after 30 min pretreatment with the products tested. The volunteers were treated for 9 days. The irritant cutaneous reactions were quantified by erythema score, transepidermal water loss, and chromametry. The results showed a specific profile of efficacy against the 4 irritants used. For all creams a significant protective effect was obtained against irritation by sodium lauryl sulfate, sodium hydroxide and lactic acid in different degrees. Less efficacy was observed against toluene. Even an amplification of inflammation by pretreatment with 1 product could be demonstrated. The results indicate that a 1-week period of cumulative irritation might be enough to evaluate the efficacy of protective creams against most irritants.

Adult↗
PubMed1997

Evaluation of decoquinate to treat experimental cryptosporidiosis in kids.

The purpose of this trial was to evaluate the effects of decoquinate at 2.5 mg/kg/day for 21 days to prevent an experimental cryptosporidiosis in kids. Twenty 1-day-old male kids (French Alpin), fed initially goat colostrum heated 1 h at 56 degrees C and fed twice daily with nonmedicated milk replacer, were assigned into 2 groups. Kids of both groups were orally inoculated with 10(6) Cryptosporidium parvum (D0 = inoculation day). Group A kids were kept as nonmedicated controls and group B kids were orally medicated with 2.5 mg/kg/day of decoquinate (Deccox L. Rhône Poulenc Animal Nutrition) for 21 days from D-3 to D17. The studied criteria were body weight gain, oocyst shedding and specific anti-C. parvum immune response. In group A, the inoculation was not followed by mortality; but only by diarrhea and high oocyst shedding. Decoquinate reduced the severity of cryptosporidiosis in group B kids. The treatment prevented episodes of diarrhea and weight gain decrease for the D0-D7 and D0-D14 disease periods but did not allow a better final weight gain. The oocyst shedding was decreased in number and in duration. This parasitic development has induced a specific anti-C. parvum immune response. This drug is well-tolerated by animals and may be recommended in the prevention of ruminant cryptosporidiosis, a disease which has very limited treatment options.

Animals↗
PubMed1997

Interference of HIV-1 Nef in the sphingomyelin transduction pathway activated by tumour necrosis factor-alpha in human glial cells.

OBJECTIVE: The HIV-1 nef gene product, thought to interact with mediators of cell signalling, is overexpressed during the restricted HIV-1 infection of human astrocytes. This infection can be reactivated following exposure to tumour necrosis factor (TNF)-alpha. We examined the possibility that Nef alters the TNF-alpha-induced cell signalling in astroglioma cells through the sphingomyelin pathway. METHODS: Sphingomyelinase activation by TNF-alpha was analysed in U251MG glial cells constitutively expressing Nef and compared with U251MG cells stably transfected with the expression vector alone. The consequent effect on the cellular proliferative response and induction of nuclear factor NF-kappa B and AP-1 binding activities were examined. RESULTS: A marked enhancement in the levels of ceramide, a product of the sphingomyelin hydrolysis, was observed in U251MG-Nef upon stimulation with TNF-alpha. In contrast, ceramide levels in control cells were barely increased under similar conditions. A concomitant reduction of sphingomyelin level occurred in U251MG-Nef cells. In addition, the reduced survival rate of U251MG cells resulting from TNF-alpha activation was prevented in the presence of Nef. Furthermore, electrophoretic mobility shift assays indicated that nef expression inhibits AP-1 activation without altering the induction of NF-kappa B. CONCLUSION: These results strongly suggest that nef expression in U251MG cells modulates the sphingomyelinase signalling pathway triggered by TNF-alpha, thus leading to important modifications in the activation and proliferation of glial cells. They also provide new insights to explain the widespread reactive astrogliosis observed in AIDS-associated neuropathological disorders.

Cells, Cultured↗
PubMed1997

Perception of risk, choice of maternity site, and socio economic level of twin mothers.

The objective of this study was to determine if access to high level health facility (level 3 perinatal center) is related to socio-economic level of the mother and to her perception of risk for a twin birth. A retrospective questionnaire was administrated to the mothers of twins during the first post parum days in each of the 27 maternity sites within a defined geographical district near Paris (Hauts de Seine). The survey instrument was designed to precisely characterize the socioeconomic status of the parents, to measure the perceived risk for the twins expressed by the mother, to measure the relationship between the choice of a maternity site (level 1, 2 or 3) by socioeconomic level, and to measure the fetal and neonatal death rates by socioeconomic status. The opinion of mothers of twins about specific risk for her and for her children is very different by socioeconomic levels, as is the choice of level 3. This is discussed with the rates of fetal and neonatal death rates by socioeconomic level. In the absence of a policy of regionalization of perinatal care, the discriminant factor for access to high level care (level 3 maternity site) is the socioeconomic level.

Cohort Studies↗
PubMed1996

C2-ceramide primes specifically for the superoxide anion production induced by N-formylmethionylleucyl phenylalanine (fMLP) in human neutrophils.

Activated sphingomyelinases release ceramide molecules believed to be involved in intracellular signalling. The present study investigated whether soluble C2-ceramide modulates some of the effects of N-formylmethionylleucyl phenylalanine (fMLP) and other agonists on human neutrophils (or polymorphonuclear leukocytes-PMN); principally superoxide anion (O2-) production. The preincubation of PMN for 15 min with C2-ceramide increased by up to almost 3-fold the amounts of O2- generated in response to 0.1 and 1 microM fMLP. Priming was detected at C2-ceramide concentrations of 2 microM to 4 microM per million PMN. Though less potent than C2-ceramide, C6-ceramide (N-hexanoylsphingosine) could prime for O2- generated in response to 0.1 microM fMLP, with maximal effects obtained at 10-20 microM. In contrast, micromolar concentrations of sphingosine, dihydroceramide, and ceramide-phosphate, failed to exert any potentiating effect on fMLP-induced O2- generation. As expected, TNF-alpha (1000 U/ml), also primed for fMLP-induced O2- production; however, the combination of TNF-alpha and C2-ceramide showed no additive effect. Moreover, S. aureus sphingomyelinase (0.1 U/ml), was unable to reproduce the priming effects of C2-ceramide and TNF-alpha. C2-ceramide at 2 microM did not enhance the production of O2- induced by 100 nM recombinant human interleukin-8 (IL-8), leukotriene B4 (LTB4), platelet-activating factor (PAF) or 20 mM sodium fluoride (NaF). Furthermore, C2-ceramide (2 microM) did not enhance the mobilization of calcium, the release of arachidonic acid or the accumulation of phosphatidylethanol, induced by 100 nM fMLP. This suggests that probably neither phospholipases C, A2 or D (PLC, PLA2, PLD) were involved in the priming effect by C2-ceramide. However, C2-ceramide inhibited in a dose-related manner the production of O2- induced by phorbol 12-myristate 13-acetate (PMA) and mezerein. Furthermore, PMA-stimulated PLD activity was also significantly reduced by a preincubation of PMN with C2-ceramide. The priming of O2- production by C2-ceramide could involve yet unidentified mechanisms specific for fMLP, or it might imply that cytokines such as TNF-alpha have different mechanisms than C2-ceramide.

Arachidonic Acid↗
PubMed1996

Comparative effects of haloacetic acids in whole embryo culture.

A major class of disinfection by-products in drinking water are the haloacetic acids. Both dichloro- and trichloroacetic acids are teratogenic when administered to rats throughout organogenesis. However, there is little information regarding the developmental toxicity of other haloacetic acids. Therefore, 3-6 somite staged CD-1 mouse embryos were exposed to acetic acid (AA) or mono- (M), di- (D), and tri- (T) substituted fluoro- (F), chloro- (C), or bromo- (B) acetic acids in whole embryo culture in order to evaluate the effects of these agents on development. A 24 hour exposure to the haloacetic acids produced dysmorphogenesis. Effects on neural tube development ranged from prosencephalic hypoplasia to non-closure defects throughout the cranial region. Exposure to the haloacetic acids affected optic development, produced malpositioned and/or hypoplastic pharyngeal arches, and resulted in perturbation of heart development. In order to determine the relative toxicities of these agents, benchmark concentrations were calculated as the lower 95% confidence interval of the concentration that produced a 5% increase in neural tube defects. The benchmark concentrations occurred over a wide range with DFA (5912.6 microM) and MBA (2.7 microM) at the extremes. Using the benchmark concentrations to compare the chemicals gives a ranking of the agents in order of increasing potency as: DFA < TFA < DCA < AA < TBA < or = TCA < DBA < MCA < MBA. TCA and DCA have demonstrated ability to disrupt development in vivo but were among the least potent haloacetic acids in vitro. Because of the potential for widespread exposure to haloacetic acids in drinking water and the incomplete toxicity profile of these chemicals, further work on their developmental effects is warranted.

Abnormalities, Drug-Induced↗