Biomedical subjects

C Robert

Publications and source records attributed to C Robert.

At least 19 recordsLinked to original sources

PubMed2006

Climatically driven emissions of hydrocarbons from marine sediments during deglaciation.

Marine hydrocarbon seepage emits oil and gas, including methane ( approximately 30 Tg of CH(4) per year), to the ocean and atmosphere. Sediments from the California margin contain preserved tar, primarily formed through hydrocarbon weathering at the sea surface. We present a record of variation in the abundance of tar in sediments for the past 32,000 years, providing evidence for increases in hydrocarbon emissions before and during Termination IA [16,000 years ago (16 ka) to 14 ka] and again over Termination IB (11-10 ka). Our study provides direct evidence for increased hydrocarbon seepage associated with deglacial warming through tar abundance in marine sediments, independent of previous geochemical proxies. Climate-sensitive gas hydrates may modulate thermogenic hydrocarbon seepage during deglaciation.

Journal Article↗

PubMed2006

The complete genome sequence of Lactobacillus bulgaricus reveals extensive and ongoing reductive evolution.

Lactobacillus delbrueckii ssp. bulgaricus (L. bulgaricus) is a representative of the group of lactic acid-producing bacteria, mainly known for its worldwide application in yogurt production. The genome sequence of this bacterium has been determined and shows the signs of ongoing specialization, with a substantial number of pseudogenes and incomplete metabolic pathways and relatively few regulatory functions. Several unique features of the L. bulgaricus genome support the hypothesis that the genome is in a phase of rapid evolution. (i) Exceptionally high numbers of rRNA and tRNA genes with regard to genome size may indicate that the L. bulgaricus genome has known a recent phase of important size reduction, in agreement with the observed high frequency of gene inactivation and elimination; (ii) a much higher GC content at codon position 3 than expected on the basis of the overall GC content suggests that the composition of the genome is evolving toward a higher GC content; and (iii) the presence of a 47.5-kbp inverted repeat in the replication termination region, an extremely rare feature in bacterial genomes, may be interpreted as a transient stage in genome evolution. The results indicate the adaptation of L. bulgaricus from a plant-associated habitat to the stable protein and lactose-rich milk environment through the loss of superfluous functions and protocooperation with Streptococcus thermophilus.

Bacterial Proteins↗

PubMed2006

Impact of surgery on advanced gastrointestinal stromal tumors (GIST) in the imatinib era.

BACKGROUND: The role for surgery in patients with "unresectable" gastrointestinal stromal tumors (GIST) treated with imatinib is still not defined. The objective of this retrospective study was to evaluate the feasibility and benefit of this secondary surgery. METHODS: Progression-free survival (PFS) in a group of patients who underwent secondary surgery was compared to that of patients treated exclusively with imatinib. RESULTS: Of 180 patients with unresectable GIST treated with Imatinib, 22 (12%) underwent secondary surgery, following which one patient achieved a complete radiological response, 19 achieved a partial response (PR), in one patient the disease was stable, and in one patient there was reactivation of local occlusive disease after an initial PR. No patient with overall progression was to undergo surgery. At the beginning of imatinib therapy, five patients with metastases underwent emergency surgery [hemorrhage (n = 3) due to rupture of large necrotic masses], which ultimately resulted in three of the five patients dying postoperatively. A macroscopically complete resection was achieved in all primary tumors (5/5) and in ten of the 17 metastases. Pathological analysis revealed two complete response (CR) and 17 PR, and no treatment effect was evidenced in three patients. Two-year overall survival after surgery was 62%. The median PFS calculated from the initiation of imatinib therapy was 18.7 months for all operated patients and 23.4 months after planned surgery. CONCLUSION: Primary tumors that become amenable to surgery with prior imatinib therapy, evolving necrosis and localized progression (to avoid life-threatening complications) could benefit from this secondary surgery. For the majority of other residual lesions, the potential benefit of secondary surgery should be evaluated in randomized studies in the future since PFS is similar to that reported among non-operated patients.

Adolescent↗

PubMed2005

Limb salvage with isolated perfusion for soft tissue sarcoma: could less TNF-alpha be better?

BACKGROUND: The optimal dose of TNF-alpha delivered by isolated limb perfusion (ILP) in patients with locally advanced soft tissue sarcoma is still unknown. PATIENTS AND METHODS: Randomised phase II trial comparing hyperthermic ILP (38-40 degrees ) with melphalan and one of the four assigned doses of TNF-alpha: 0.5 mg, 1 mg, 2 mg, and 3/4 mg upper/lower limb. The main end point was objective tumour response on MRI. Secondary end points were histological response, rate of amputation and toxicity. Resection of the remnant tumour was performed 2-3 months after ILP. The sample size was calculated assuming a linear increase of 10% in the objective response rates between each dose level group. RESULTS: One hundred patients (25 per arm) were included. Thirteen per cent of patients had a systemic leakage with a cardiac toxicity in six patients correlated with high doses of TNF-alpha. Objective tumour responses were: 68%, 56%, 72% and 64% in the 0.5 mg, 1 mg, 2 mg and 3 or 4 mg arms, respectively (NS). Sixteen per cent of patients were not operated, 71% had a conservative surgery and 13% were amputated with no difference between the groups. With a median follow-up of 24 months, the 2 year overall and disease-free survival rates (95% CI) were 82% (73% to 89%) and 49% (39% to 59%), respectively. CONCLUSION: At the range of TNF-alpha doses tested, there was no dose effect detected for the objective tumour response, but systemic toxicity was significantly correlated with higher TNF-alpha doses. Efficacy and safety of low-dose TNF-alpha could greatly facilitate ILP procedures in the near future.

Adult↗

PubMed2005

Effect of a preparation containing a fucose-rich polysaccharide on periorbital wrinkles of human voluntaries.

BACKGROUND: Skin aging is accompanied by wrinkle formation. At some sites, as the periorbital skin, this is a relatively early phenomenon, variable from one woman to the other and even between the right and left eye. PURPOSE: We tested the effect of a preparation with fucose-rich oligo- and polysaccharide (FROP-3) on periorbital wrinkles (crow's feet) on a team of voluntaries. METHOD: The efficiency of a preparation containing as active principle a fucose-rich polysaccharide in a base-cream for the treatment of temporal periorbital wrinkles on 20 voluntary women was tested as follows: the women applied the cream twice a day for 4 weeks. Negative replicas were taken on the periorbital skin before and after 4 weeks of application of the cream. The results were evaluated by semi-automated morphometry on the plastic replicas and expressed as the 'wrinkle-factor' obtained by multiplying total wrinkle length in millimeters by the average wrinkle width. RESULTS: After 4 weeks of treatment, there was a significant improvement of the periorbital wrinkles for the majority of the voluntary team who tested the cream. On the 29 periocular wrinkles examined 65% showed an improvement at the end of the treatment. In two cases, the improvement was 100% on one eye (disappearance of the crow's feet) and of 75% and 79% on the other eye. On six eyes, there was no significant change after the end of the treatment, and on four eyes a worsening was observed. The age-dependent modifications showed that improvement was independent of age and was the result of individual skin reactions to the cream. The occurrence and the severity of crow's feet is highly individual, and differs from one side of the face to the other for the same person. These strong individual variations explain the highly variable results, not only from one woman to the other but also comparing one side of the face to the other for the same person. CONCLUSION: Under the effect of 4 weeks of treatment with the FROP-3-containing cream, most of the voluntaries had their periorbital wrinkles attenuated and some women showed a total regression of crow's feet on one of their eyes.

Adult↗

PubMed2005

Rickettsia felis, from culture to genome sequencing.

Rickettsia felis has been recently cultured in XTC2 cells. This allows production of enough bacteria to create a genomic bank and to sequence it. The chromosome of R. felis is longer than that of previously sequenced rickettsiae and it possess 2 plasmids. Microscopically, this bacterium exhibits two forms of pili: one resembles a conjugative pilus and another forms hair-like projections that may play a role in pathogenicity. R. felis also exhibits several copies of ankyrin-repeat genes and tetratricopeptide encoding gene that are specifically linked to pathogenic host-associated bacteria. It also contains toxin-antitoxin system encoding genes that are extremely rare in intracellular bacteria and may be linked to plasmid maintenance.

Animals↗

PubMed2004

Chronobiology of labour pain perception: an observational study.

BACKGROUND: Circadian variation may affect many biological and pharmacological phenomena. METHODS: To assess circadian variations in labour pain perception, 222 consecutive nulliparous women with uncomplicated pregnancy, spontaneous labour, cervical dilatation (3-5 cm), ruptured membranes and normal fetal heart rate tracings were studied. Visual analogue pain scores (VAPS) were analysed and divided into four periods: night (1:01 a.m. to 7:00 a.m.), morning (7:01 a.m. to 1:00 p.m.), afternoon (1:01 p.m. to 7:00 p.m.) and evening (7:01 p.m. to 1:00 a.m.). VAPS were also compared between daytime (morning+afternoon) and nocturnal (evening+night) periods. RESULTS: Daytime mean VAPS were lower than nocturnal scores [75.6 (15.1) vs 85.7 (14.1), P<0.0001]. VAPS were lower in the morning than in the afternoon, evening and night periods (anova, P<0.0001). CONCLUSION: Labour pain perception appears to be chronobiological, and this might be taken into account when enrolling parturients in studies designed to assess or treat labour pain.

Adolescent↗

PubMed2004

p66shc, but not p53, is involved in early arrest of in vitro-produced bovine embryos.

High embryo loss occurs in the first week of bovine embryo development, with a high percentage of embryonic arrest. We hypothesized that arrested embryos enter a 'senescence-like state' and that both the cell cycle regulatory protein p53 and the stress-related protein p66(shc), which are involved in the onset of senescence in somatic cells, are responsible for this early embryonic arrest. In our in vitro production system, 13.5 +/- 0.5% of embryos arrest at the 2-4-cell stage. First cleavage occurs between 26 and 48 h post insemination (hpi), with early cleaving embryos showing only 0.6 +/- 0.3% arrest, with later cleaving embryos exhibiting up to 14.2 +/- 0.9% arrest. We compared 2-4-cell embryos collected at 28 hpi with those arrested at the 2-4-cell stage collected at day 8 post insemination. Quantification by real-time PCR and by semi-quantitative immunofluorescence showed significantly higher p66(shc) mRNA and protein levels in both arrested and late cleaving embryos versus 28 hpi embryos. By comparison, no significant changes in p53 mRNA, protein and phosphorylation levels were detected. Taken together, these results demonstrate that embryonic developmental potential is related to the time of first cleavage and that p66(shc), but not p53, is up-regulated in early arrested in vitro-produced bovine embryos.

Adaptor Proteins, Signal Transducing↗

PubMed2004

Different culture media requirements of IVF and nuclear transfer bovine embryos.

Important differences exist between in vitro fertilized (IVF) and nuclear transfer (NT) bovine embryos. Studies have shown that although in vitro development is comparable, post-implantation survival is greatly reduced in NT embryos. In this study, we compare serum and bovine serum albumin (BSA) supplementation during oocyte maturation and embryo culture of IVF and NT embryos. In experiment 1, oocytes and embryos were randomly distributed into different treatment groups consisting of synthetic oviductal fluid (SOF) medium supplemented with either serum, fatty acid-free BSA (FAF) or fraction V BSA during maturation and/or culture to assess IVF embryo development. In experiment 2, oocytes were matured in SOF + serum or SOF + FAF and reconstructed embryos were cultured in SOF + FAF to assess NT embryo development. Among the IVF treatment groups, a greater number of blastocysts were observed in the steer serum (SER) group (IVM and IVC in SOF + serum) on day 6; however, no significant differences were seen in blastocyst development from day 8 onwards. Hatching frequencies on days 8 and 9 were significantly greater in groups with serum, with the exception of FAF (IVM and IVC in SOF + FAF) on day 9. For the NT treatment groups, the presence of serum during IVM resulted in a higher proportion of MII oocytes and increased blastocyst development and hatching rates were compared with supplementation of FAF. These results indicate that both serum and FAF provide comparable embryo development for IVF but not for NT bovine embryos.

Animals↗

PubMed2003

Effect of a fucose-rich polysaccharide preparation on the age-dependent evolution of the skin surface micro-relief.

It was demonstrated previously that the evaluation of the microdepressionary skin surface relief by semi-automated computerised morphometry enables the determination of several of its geometrical parameters, such as, the average number of polygons in a given microscopic field, and/or the average surface of the polygons. Using this procedure, it could be shown in a study on about 100 persons, males and females, aged from 6 months to 89 years that these parameters undergo age-related alterations. These alterations are faster at younger ages, slow down at middle ages and accelerate after 50-60 years again. Taken at a sun-protected site, the interior face of the forearm, close to the elbow, this test reflects the effect of chronological ageing of the skin surface micro-relief. In the present work we tested the effect of a preparation containing a fucose-rich polysaccharide as active principle on the microdepressionary skin surface micro-relief evaluated by a morphometric method, comparing results before treatment and after 4 weeks of treatment. We could demonstrate on 20 female volunteers, aged from 39 to 71 years, that after 4 weeks of treatment with the abovementioned preparation there was a significant improvement of the skin surface relief, as shown by the displacement of geometrical characteristics of 17 treated skins out of 20, towards a "younger" pattern, as for instance the increase of the average number of polygons in a given microscopic field. This improvement was less than 15% of the untreated value for two persons, and more than 15% for 15 women out of 20. The average improvement was 37.16%, and for the 15 persons showing more than 15% improvement, it was nearly 50%, corresponding to a decrease of apparent age by 10-15 years. These results suggest that a treatment with the fucose-rich polysaccharide preparation can slow down human skin ageing and even can reverse age-dependent skin alterations.

Adult↗

PubMed2003

Gene therapy to target dendritic cells from blood to lymph nodes.

Peripheral lymph nodes (PLN) are strategic microenvironments where antigen-presenting dendritic cells (DC), loaded with environmental antigens, and naive lymphocytes meet to initiate immune responses. The unique capacity of DC to induce primary immune responses has led to their use in clinical medicine; however, delivering DC to lymph nodes is problematic. Intravenously injected DC cannot access to PLN, while DC injected into tissue migrate inefficiently through lymphatics to PLN. We achieved DC targeting to T-cell areas of PLN by endowing DC with a novel receptor for peripheral node addressin (PNAd), an adhesion molecule present on the lymph node venular endothelium. This novel receptor is a chimeric E/L-selectin (ELS) that, we have previously shown, binds to PNAd. DC were genetically modified by retroviral transduction to express ELS. ELS expression was targeted to tips of microvilli, and mediated rolling of DC on PNAd both in vivo and in vitro. Such genetically engineered DC could extravasate directly from blood through the lymph node endothelium as opposed to nontransduced DC. This study provides evidence that the trafficking of DC can be modified using gene transfer technologies. More efficient delivery of DC to PLN should assist the development of improved vaccination strategies.

Adoptive Transfer↗

PubMed2003

Presence of LH receptor mRNA in granulosa cells as a potential marker of oocyte developmental competence and characterization of the bovine splicing isoforms.

As the expression of the LH receptor (LH-R) in granulosa cells is thought to be associated with later stages of folliculogenesis, this study was undertaken to evaluate the presence of LH-R mRNA as a suitable marker for developmental competence of oocytes. Granulosa cells and cumulus-oocyte complexes (COCs) were recovered from cows that had received ovarian stimulation. The COCs were subjected to embryo production procedures in vitro to assess the embryonic potential of the oocyte, and the corresponding granulosa cells were used to evaluate the presence of LH-R mRNA by RT-PCR. The presence of LH-R transcripts in granulosa cells is not a key characteristic of a follicle bearing a competent oocyte, although a higher proportion of oocytes reach the blastocyst stage when LH-R mRNA is detected in the granulosa cells. Different LH-R isoforms were cloned and sequence discrepancies among six of the isoforms enabled the design of specific oligonucleotides to study the presence of the isoforms in different follicular cells. All LH-R transcripts studied and the 80 kDa protein product corresponding to the full length receptor were found in granulosa cells of small (< 4 mm) and large (> 5 mm) follicles. When the granulosa cells were cultured, the transcripts were downregulated by the culture conditions; downregulation was more acute in granulosa cells from small follicles. The addition of LH to the culture media enhanced LH-R mRNA downregulation. The presence of several LH-R transcript isoforms was tissue specific and in the theca cells LH-R mRNA was restricted mainly to cells from larger follicles. This finding indicates that the expression and the splicing of LH-R mRNA are regulated in a cell-specific and follicular size-specific manner.

Alternative Splicing↗

PubMed2003

The use of genomics and proteomics to understand oocyte and early embryo functions in farm animals.

Oocyte maturation, a simple and visible phenomenon, is about to be transformed into a complex and not so visible molecular cascade leading to the marking of the following generation. The study of oocyte maturation in mammals is progressively changing towards a more molecular approach. This review addresses the main challenges in the study of RNA extraction and quantification in oocytes and embryos as well as the importance of the mRNA maturation. The identification of specific genes in oocytes and embryos is now possible with the use of powerful tools, such as library analysis or subtractions, DNA array, comparative analysis of databanks from other mammals or animals and two-dimensional gel electrophoresis analysis. Finally, RNA interference is a useful tool for studying gene function by knocking out the activity of specific genes and will be used in oocytes and embryos.

Animals↗

PubMed2003

Electrochemotherapy: a new treatment of solid tumors.

Electrochemotherapy is a new local treatment of the solid tumors that can be defined as the local potentiation, by means of permeabilizing electric pulses, of the antitumor activity of non-permeant (e.g. bleomycin) or low-permeant (e.g. cisplatin) anticancer drugs. The electric pulses are delivered locally on the solid tumors, after the intravenous or intralesional injection of the chemotherapy agent. In this review, the basis of the electrochemotherapy are recalled. Then, after summarizing clinical data, we present some results of the European project Cliniporator, as well as the new pulse generator, the Cliniporator, that incorporates new features resulting from this research project, and that is fully conceived for a clinical use. Finally, future perspectives are discussed.

Animals↗

PubMed2002

Genome sequence of the plant pathogen Ralstonia solanacearum.

Ralstonia solanacearum is a devastating, soil-borne plant pathogen with a global distribution and an unusually wide host range. It is a model system for the dissection of molecular determinants governing pathogenicity. We present here the complete genome sequence and its analysis of strain GMI1000. The 5.8-megabase (Mb) genome is organized into two replicons: a 3.7-Mb chromosome and a 2.1-Mb megaplasmid. Both replicons have a mosaic structure providing evidence for the acquisition of genes through horizontal gene transfer. Regions containing genetically mobile elements associated with the percentage of G+C bias may have an important function in genome evolution. The genome encodes many proteins potentially associated with a role in pathogenicity. In particular, many putative attachment factors were identified. The complete repertoire of type III secreted effector proteins can be studied. Over 40 candidates were identified. Comparison with other genomes suggests that bacterial plant pathogens and animal pathogens harbour distinct arrays of specialized type III-dependent effectors.

Bacterial Proteins↗

PubMed2002

Pharmacological and functional characterization of the guinea-pig B2 bradykinin receptor stably expressed in CHO-K1 cell line.

In the present study, pharmacological properties of a bradykinin B(2) receptor amplified either from guinea-pig ileum or lung and homologous to the previously reported sequence except two amino-acid changes L(124)-->P and N(227)-->Y in the receptor protein were characterized. Tritiated bradykinin ([(3)H]-BK) specifically bound to the cloned guinea-pig B(2) bradykinin receptor stably expressed in Chinese hamster ovary cells (CHO-K1) with a K(D) value of 0.29+/-0.07 nM. In competition experiments, bradykinin (BK) affinity constant value was 0.21+/-0.05 nM while the two specific kinin B(1) ligands, des-Arg(9)-bradykinin (DBK) and des-Arg(9)-Leu(8)-bradykinin (DLBK) were unable to compete with [(3)H]-BK. As the specific peptide antagonist D-Arg-[Hyp(3),Thi(5),D-Tic(7),Oic(8)]-bradykinin (HOE140), (E)-3-(6-acetamido-3-pyridil)-N-[-N-[2,4-dichloro-3-[(2-methyl-8-quinolinyl)oxymethyl]phenyl]-N-methylaminocarbonylmethyl]acrylamide (FR173657) and 1-[[3-[2,4-dimethylquinolin-8-yl)oxymethyl] - 2,4 - dichloro - phenyl]sulfonyl] - 2(S) - [[4-[4-(aminoiminomethyl)-phenylcarbonyl]piperazin-1-yl]carbonyl]pyrrolidine (LF16-0335C) exhibited a high affinity for this receptor with K(i) values of 7.34+/-2.45 nM and 8.54+/-1.55 nM respectively. BK and kallidin (KD) increased inositol phosphates (IPs) levels with EC(50) values of 0.44+/-0.12 nM and 6.88+/-0.28 nM, respectively. Neither DLBK nor DBK (0.01 nM to 10 microM) stimulated or inhibited IPs turnover and as expected HOE140 did not raise IPs production. HOE140 (0.1 microM) and LF 16-0335c (1 microM) right shifted the BK response curve with pK(B) values of 9.2+/-0.4 and 8.4+/-0.3, respectively. The results indicate that this cloned guinea-pig receptor displayed typical pharmacological properties of a bradykinin B(2) receptor and support the existence of a single B(2) receptor in this species.

Animals↗

PubMed2002

Use of the recovery check in long-distance endurance rides.

In an attempt to reduce morbidity, an additional veterinary examination is performed at the end of the hold time--the Recovery Check (RC)--of the last vet gate of all long distance endurance rides held in France. At the RC, a normal FEI-type inspection is performed combined with a cardiac recovery index (CRI): the heart rate is taken before (HR0) and 1 min after (HR1) the horse trotted for 30 m out and back. Results from 12 (130 and 160 km long) rides and based on 489 horses were analysed. Of all RC performed, 10.4% lead to elimination of the horses and lameness was the most frequent reason (45%). Among horses allowed to continue in the ride, elimination rate was significantly higher in horses with HR0 > or = 60/min compared to horses with HR0 < 60. High CRI (HR1-HR0 > or = 4) lead to greater disqualification rates only when HR0 was more than 60/min. RC appears to be useful in the assessment of a horse's fitness. However, standardisation of the examination is necessary in order to optimise its use.

Animals↗

PubMed2002

Effects of trotting speed on muscle activity and kinematics in saddlehorses.

A thorough knowledge of the horse's back and limb movements at different speeds is important in the design of training programmes and the prevention of speed-related injuries. The objective of this study was to investigate changes in muscle activity and kinematics of the trot with increased speed. To evaluate these effects, 4 Saddlehorses were recorded while trotting on a horizontal treadmill at speeds ranging from 3.5-6.0 m/s. The 3-D trajectories of skin markers on the left side of the horse and the dorsal midline of the trunk were established. Electrical activity was obtained simultaneously from 6 muscles using surface electrodes. Ten consecutive strides were analysed for each horse at each of the 5 velocity steps. The increase in speed resulted in a decrease in stride and stance phase duration, increased muscle activity and range of motion of the limbs, but a decrease in back movements. During the stance phase, the limbs appeared more loaded, which resulted in more flexion of the joints and higher excentric muscle activity. During the swing phase, the higher concentric activity of the muscles was responsible for an increased shortening of the limbs. Understanding the effects of speed on equine locomotion is a prerequisite for the development of training programmes.

Animals↗