Biomedical subjects
Publications and source records attributed to C Richard.
Explore the source record for details and available documents.
AIMS: The aim of this study was to investigate the role of divercin V41 in inhibition and prevention of Listeria monocytogenes. METHODS AND RESULTS: Carnobacterium divergens V41 deficient in bacteriocin production was isolated and characterized by enzyme-liked immunosorbent assay, multiplex polymerase chain reaction and bacteriocin diffusion test. Carnobacterium divergens V41 (divercin+) and Carnobacterium divergens V41C9 (divercin-) were grown in the presence of L. monocytogenes in smoked salmon model medium. Carnobacterium divergens V41, but not C. divergens V41C9, was able to inhibit growth of L. monocytogenes. The results indicate that inhibition of L. monocytogenes in the presence of C. divergens V41 is because of the production of divercin V41 and not to a nutritional advantage. CONCLUSIONS: Carnobacterium divergens V41 may be a promising agent in food safety. SIGNIFICANCE AND IMPACT OF THE STUDY: The study demonstrates a potential use of a bacteriocin producing lactic acid bacteria in the area food protection.
The purpose of this study was to evaluate the impact of repeated follicular puncture used in the ovum pick-up technique on the welfare of cows. The evaluation relies on the physiological measurement of stress, milk production criteria, immune status, and the histological examination of ovaries. Two groups of five Holstein cows were submitted to epidural anaesthesia and genital palpation with insertion of an intravaginal ultrasound probe for transvaginal puncture (the puncture was not performed in the control group). Animals were manipulated twice a week for 8 weeks (16 manipulation sessions). The blood cortisol concentrations increased after each session; however, the concentrations were the same in both the control and the punctured groups. Two adrenocorticotrophic hormone challenge tests, performed before the first session and after the last session, showed an unchanged adrenal sensitivity through repeated puncture sessions. The transvaginal puncture did not affect milk production, or blood and milk somatic cell counts. Ovariectomies were performed on another group of four Holstein cows at various intervals (0 to 30 days) after five similar puncture sessions. Histological examination of the ovaries 4 days after puncture revealed blood-filled follicles and haemorrhagic foci in ovarian stroma, but the examination 30 days after the last puncture session demonstrated very limited, if any, fibrosis. On the basis of the criteria chosen for this study, repeated transvaginal follicular puncture on its own does not impact adversely on the welfare of cows.
There have been few studies on a possible maternal influence on in vitro embryo production in cows. The objective of this study was to evaluate the maternal influence on oocyte production and in vitro blastocyst formation rate using repeated ovum pick-up and in vitro fertilization. Six contemporary cows raised on the same farm and with varied genetic origins were submitted to 42 weeks of ovum pick-up organized into four series. Collected oocytes were fertilized in vitro with spermatozoa from a different bull for each series. In total, 1933 oocytes were recovered from 3936 follicles with a recovery rate of 57.2% and a mean oocyte collection of 4.6+/-0.2 (mean+/-SEM) per animal per session. Animals were ranked according to their oocyte production. The best oocyte donor was the same female in all four series. No relationship was identified between oocyte production and blastocyst production rate (r=-0.08). The mean blastocyst rate was 28.8% with significant variation among animals. The best and the worst blastocyst producers were always the same animals independent of the semen used. The results of the present study support the hypothesis that in cattle, the oocyte donor influences the production of blastocysts. Furthermore, they demonstrate that oocyte and embryo production are independent factors. Further studies are necessary to identify the maternal or oocyte factors responsible for such differences.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
1.3 PZT-polymer composites were fabricated using the dice and fill method with various PZT types and volume fractions. These composites were evaluated for power underwater transducer applications with an air backed and no matching layer configuration. Electrical input and acoustical output powers were monitored as a function of the drive level. Total acoustic power densities of 30 W/cm2 were obtained with a P189/epoxy piezocomposite vibrating at 350 kHz with a low duty cycle (1-5%) and with a 90% efficiency. Power densities up to 20 W/cm2 were measured with a 50% duty cycle. Evolution and destruction of the transducers were monitored versus increasing averaged power. It was observed that better efficiencies were obtained with low volume fraction configurations allowing natural acoustic impedance matching to water. It was found that hard PZT type (Navy III) are optimal compositions even for piezocomposite transducers. It is shown that, unlike a common belief, the polymer mechanical losses are comparable to those of the active ceramic justifying that 1.3 piezocomposites are suited for low-cost power applications. In fact, the main limitation induced by the polymer phase is a strong thermal breakdown when the temperature of the transducer approaches the glass transition region of the polymer. Measurements of the polymer losses as a function of the temperature were obtained confirming this point and offering interesting new alternatives for future composite power transducers.
Humic and fulvic acids extracted from soils of different genesis were investigated for their ability to photoinduce the transformation of fenuron (2 x 10(-4) mol(-1)) at 365 nm. The ratio of the initial rate of fenuron consumption over the rate of light absorption by humic substances was found to be higher for fulvic acids (range 2.0 x 10(-3) to 9.0 x 10(-5)) than for humic acids (range 1.7 x 10(-4) to - 3.6 x 10(-5)). Within the FAs population, this ratio decreased as the specific absorption coefficient at 365 nm increased. It seems therefore that most of 365-nm absorbing components have no photoinductive activity and even reduce that of photoinductive chromophores.
The ventral striatum is the part of the striatum associated with reward and goal-directed behaviors, which are mediated in part by inputs from the amygdala. The ventral striatum is divided into 'shell' and 'core' subterritories which have different connectional, histochemical and pharmacological properties. Behavioral studies also indicate that subterritories of the ventral striatum are differentially involved in specific goal-directed behaviors. The amygdala is a heterogeneous structure which has multiple nuclei involved in processing emotional information. While the existence of an amygdalostriatal pathway has long been established, the relationship between amygdaloid afferents and specific subterritories of the ventral striatum is not known. In this study we operationally defined the ventromedial striatum as the region receiving cortical inputs primarily from the orbital and medial prefrontal cortex. We placed retrograde tracer injections into subregions of the ventromedial striatum of macaques monkeys to determine the relative contribution of specific amygdaloid inputs to each region. Calbindin-D28k immunostaining was used to further define the shell subterritory of the ventromedial striatum. Based on these definitions, the amygdala innervates the entire ventromedial striatum, and has few to no inputs to the central striatum. The basal and accessory basal nuclei are the major source of input to the ventromedial striatum, innervating both the shell and ventromedial striatum outside the shell. However, a restricted portion of the dorsomedial shell receives few basal nucleus inputs. Afferent inputs from the basal nucleus subdivisions are arranged such that the parvicellular subdivision projects mainly to the ventral shell and core, and the magnocellular subdivision targets the ventral shell and ventromedial putamen. In contrast, the intermediate subdivision of the basal nucleus projects broadly across the ventromedial striatum avoiding only the dorsomedial shell. The shell has a specific set of connections derived from the medial part of the central nucleus and periamygdaloid cortex. Within the shell, the dorsomedial region is distinguished by additional inputs from the medial nucleus. The ventromedial caudate nucleus forms a unique transition zone with the shell, based on inputs from the periamygdaloid cortex. Together, these results indicate that subterritories of the ventromedial striatum are differentially modulated by amygdaloid nuclei which play roles in processing olfactory, visual/gustatory, multimodal sensory, and 'drive'-related stimuli.
Although healthy animals are born after nuclear transfer with somatic cells nuclei, the success of this procedure is generally poor (2%-10%) with high perinatal losses. Apparently normal surviving animals may have undiagnosed pathologies that could develop later in life. The gross pathology of 16 abnormal bovine fetuses produced by nuclear transfer (NT) and the clinical, endocrinologic (insulin-like growth factors I and II [IGF-I and IGF-II], IGF binding proteins, post-ACTH stimulation cortisol, leptin, glucose, and insulin levels), and biochemical characteristics of a group of 21 apparently normal cloned calves were compared with those of in vitro-produced (IVP) controls and controls resulting from artificial insemination. Oocytes used for NT or IVP were matured in vitro. NT to enucleated oocytes was performed using cultured adult or fetal skin cells. After culture, Day 7, grade 1-2 embryos were transferred (one per recipient). All placentas and fetuses from clones undergoing an abnormal pregnancy showed some degree of edema due to hydrops. Mean placentome number was lower and mean placentome weight was higher in clones than in controls (69.9 +/- 9.2 placentomes with a mean weight of 144.3 +/- 21.4 g in clones vs. 99 and 137 placentomes with a mean individual weight of 34.8 and 32.4 g in two IVP controls). Erythrocyte mean cell volume was higher at birth (P < 0.01), and body temperature and plasma leptin concentrations were higher and T4 levels were lower during the first 50 days and the first week (P < 0.05), respectively, in clones. Plasma IGF-II concentrations were higher at birth and lower at Day 15 in clones (P < 0.05). Therefore, apparently healthy cloned calves cannot be considered as physiologically normal animals until at least 50 days of age.
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.
Sodium butyrate induced cell cycle arrest in mammalian cells through an increase in p21Waf1/Cip1, although another study showed that this arrest is related to pRB signaling. We isolated variants of HeLa cells adapted to growth in 5 mm butyrate. One of these variants, clone 5.1, constitutively expressed elevated levels of p21Waf1/Cip1 when incubated in regular growth medium and in the presence of butyrate. Despite this elevated level of p21Waf1/Cip1, the cells continue to proliferate, albeit at a slower rate than parental HeLa cells. Western blot analyses showed that other cell cycle regulatory proteins were not up-regulated to compensate for the elevated expression of p21Waf1/Cip1. However, cyclin D1 was down-regulated by butyrate in HeLa cells but not in clone 5.1. We conclude that continued expression of cyclin D1 allowed clone 5.1 to grow in the presence of butyrate and elevated levels of p21Waf1/Cip1.
The rightward orientation bias of neglect patients has been shown to be decreased by postural changes, suggesting that afferences coding the posture relative to gravity might influence the body-centred spatial reference frame. In order to test this hypothesis, we evaluated the effects of plantar stimulations on the subjective straight-ahead (SSA) of two neglect patients presenting with a strong rightward shift, as well as two non-neglect patients and three normal subjects. Vibratory or electrical stimulations were applied to the left or right plantar sole. Data showed that these manipulations influenced the SSA position in neglect patients only. The observed improvement could be explained by a direction-specific effect of vibration, in addition to a non-specific activation induced by both stimulations.
Acifluorfen was irradiated in pure water at various excitation wavelengths and pH values. Numerous photoproducts were obtained which were identified by [1H]NMR and/or HPLC-MS/MS. The main reaction pathways were photo-decarboxylation, photo-cleavage of the ether bonding with formation of phenolic compounds, photo-dechlorination and photo-Claisen type rearrangement. Decarboxylation was observed in acidic and neutral media whereas cleavage of the ether bonding dominated in basic media. The photo-Claisen type rearrangement only occurred on excitation at short wavelengths. The quantum yield of photolysis was significantly lower at 313 nm (6.1 x 10(-5)) than at 254 nm (2.0 x 10(-3)). The photoreactivity of acifluorfen was then studied in conditions approaching environmental conditions. Acifluorfen was dissolved in pure water, in water containing humic substances or in a natural water, and exposed to solar light in June at Clermont-Ferrand (latitude 46 degrees N). In pure water, the half-life was estimated at 10 days and photo-decarboxylation accounted for 30% of the conversion. The presence of humic substances (10 mg litre-1) did not affect the rate of photo-transformation. However, the half-life of acifluorfen dissolved in the natural water was only 6.8 days.
Explore the source record for details and available documents.
OBJECTIVE: This study was conducted with the aim of testing the effects of a reduction in tidal volume (V(T)) on gastric mucosal perfusion using laser-Doppler flowmetry in patients with acute respiratory distress syndrome (ARDS). DESIGN: It was designed as a prospective study. PATIENTS: Seventeen patients with ARDS were enrolled in the study. All patients were mechanically ventilated in volume-controlled mode. Before the start of the protocol, V(T) was set at 9 ml/kg body weight. INTERVENTION: V(T) was reduced to 6 ml/kg body weight. MEASUREMENTS AND RESULTS: Measurements of systemic hemodynamic parameters and gastric mucosal blood flow (GMBF) were obtained before and after reduction of V(T). Cardiac index, heaart rate and pulmonary arterial pressure increased significantly after V(T) reduction. The increase in cardiac output was observed in all patients. However, despite a mean 25% increase in cardiac output after V(T) reduction, no significant increase in mean GMBF was observed, and individual GMBF responses were heterogeneous. CONCLUSION: V(T) reduction in patients with ARDS, despite resulting in an increase in cardiac output, did not change gastric mucosal perfusion. The heterogeneity in the individual response of GMBF to V(T) reduction could be due to opposite direct (i.e., local vasodilatory effect) and indirect (i.e., global sympathetic stimulation) effects of hypercapnia on gut vessels.
Humic acids (HAs) from three soils of different origin (Chernozem, Ferralsol and Ranker) have been fractionated by coupling size exclusion chromatography (SEC) and polyacrylamide gel electrophoresis (PAGE) on three fractions (fractions A, B, C + D) with different molecular sizes (MSs) and exactly defined electrophoretic mobility (EM). Fractions identically marked had similar EM and MS, independently of HA sources. The photoinductive properties of the whole HAs and their fractions were compared by studying the photoinduced transformation of fenuron at 365 nm. High MS fractions A and B appeared to exhibit poor photoinductive activities compared to the whole HAs, whereas low MS fraction C + D in Chernozem and Ranker were more efficient than the whole HAs. A fourth intermediary fraction containing a mixture of fractions B and C + D with small amount of D was shown to photoinduce poorly the transformation of fenuron. It was therefore concluded that the molecules capable of photoinducing the transformation of fenuron were mainly contained in fraction D. Fluorescence properties of Chernozem HA and its fractions have been tested. Fraction C + D exhibited a very similar fluorescence emission spectrum in comparison with the whole HA and in contrast, the fractions A and B emitted very weakly.
OBJECTIVE: The expression of Bcl-x(L) has been shown to be regulated during the maturation process of different hematopoietic cell lineages (i.e., erythroid cells, neutrophils, monocytes/macrophages). In the present study, we examined the expression of Bcl-x(L) in megakaryocytes derived from CD34(+) progenitors and in the megakaryoblastic cell line UT7. MATERIALS AND METHODS: Expression of Bcl-x(L) was analyzed in CD41(+) cells cultured in the presence of thrombopoietin and in UT7 cells treated with phorbol diester by Western blot, flow cytometry, and immunocytochemistry analysis. Apoptosis was determined at different culture times by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling and propidium iodide uptake. RESULTS: Bcl-x(L) but not Bcl-2 was up-regulated in the megakaryocytic population (CD41(+)) during the first 15 days of culture, which was consistent with the pattern of Bcl-x(L) expression in UT7 cells differentiated to megakaryocytes by incubation with phorbol diester. However, by day 20 of culture, the levels of Bcl-x(L) in CD41(+) cells were greatly reduced, and this expression pattern was accompanied by an increase in the number of apoptotic cells. At this culture time, we detected the presence of cytoplasmic fragments resembling proplatelets with prominent Bcl-x immunostaining, most likely due to the Bcl-x(L) isoform, in close proximity to Bcl-x(-) senescent megakaryocytes. The presence of Bcl-x(L) but not of Bcl-2 in platelets was confirmed by Western blot analysis. CONCLUSION: Although little is known regarding the functional significance of survival proteins within the megakaryocytic compartment, the changes in the Bcl-x(L) expression pattern observed in UT7 and CD41(+) cells may play a role in the survival of developing megakaryocytes and the lifespan of mature platelets.