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Biomedical subjects

C Clément

Publications and source records attributed to C Clément.

At least 19 recordsLinked to original sources
PubMed2003

Chitosan improves development, and protects Vitis vinifera L. against Botrytis cinerea.

We evaluated the potential of chitosan both to stimulate plant development and to induce protection from Botrytis cinerea in Vitis vinifera L. plantlets. The presence of 1.75% (v/v) chitogel in the culture medium was the optimal concentration for in vitro grapevine plantlet growth, as determined by measurements on enhancement of root and shoot biomass. Photosynthesis and related parameters were also stimulated in chitogel-treated plantlets. Chitogel reduced the development of Botrytis cinerea and induced cytological alterations to the pathogen. When challenged with the fungus, a significant decrease in disease incidence was observed in plants growing on medium supplemented with chitogel. Furthermore, exogenous foliar applications of chitogel to plantlets growing on chitogel-free medium sensitized them so as to be protected against Botrytis cinerea attack. Our results indicate that chitogel can be used in the vineyard as a means to attain protection against Botrytis cinerea and that its application may counteract the wide use of chemical pesticides.

Botrytis↗
PubMed2003

Stress effects of flumioxazin herbicide on grapevine ( Vitis vinifera L.) grown in vitro.

Among the herbicides used in vineyards, the pre-emergence soil-applied flumioxazin (FMX) is a recently synthesized molecule that inhibits chlorophyll biosynthesis in weed species. The aim of this work was to characterize the effects of FMX on non-target grapevine ( Vitis vinifera L. cv. Chardonnay) plantlets grown in vitro. FMX treatment (from 1 to 100 micro M) represented a stress, as revealed by measurement of several parameters. Stem and leaves underwent dehydration and a decrease in both water- and osmotic-potential. Treated plantlets exhibited concomitant accumulation of soluble carbohydrates in all tissues and of free proline in stems and leaves. Moreover, FMX caused lipid peroxidation and electrolyte leakage in leaf tissues. These results indicate that the herbicide FMX is toxic for grapevine grown in vitro. In addition to inhibiting protoporphyrinogen IX oxidase, it causes water stress and membrane alteration in tissues and, as a consequence, generates the accumulation of carbohydrates and free proline.

Benzoxazines↗
PubMed2003

Impact of flumioxazin herbicide on growth and carbohydrate physiology in Vitis vinifera L.

The impact of flumioxazin herbicide on in vitro-grown grapevine ( Vitis vinifera L. cv. Chardonnay) was investigated. The herbicide treatments (1, 10 or 100 micro M flumioxazin in MM medium) had a negative impact on photosynthesis, as revealed by a reduction in foliar chlorophyll and carotenoid contents, gas exchanges and alteration in plastid structure and, consequently, resulted in a strong inhibition of plantlet growth. Surprisingly, soluble sugars and starch accumulated in all organs, suggesting a stimulation of sugar uptake from the medium. Moreover, photosynthetic activity and starch content partially recovered within 3 weeks of treatment at the weakest herbicide concentration. These results provide new insights into the physiological responses of non-target crops to flumioxazin, showing that flumioxazin is active in photosynthetic tissues of the non-target grapevine via root uptake, which is contrary to what is mentioned in the literature, and that the in vitro-grown plantlet is a good model for investigating the physiological effects of pesticides on crop species.

Benzoxazines↗
PubMed2002

TGFbeta1 effects on functional activity of porcine thyroid cells cultured in suspension.

Thyrotropin (TSH) and transforming growth factor beta 1 (TGFbeta1) have major roles in the regulation of folliculogenesis and differentiation in thyroid cells. Isolated porcine thyroid cells cultured in the presence of TSH on a plastic surface recover a follicular architecture and exhibit normal functional properties. The addition of TGFbeta1 to the culture medium induces important morphological changes and extracellular matrix remodelling. Similarly, thyroid cells lose their ability to organify iodine and their responsiveness to adenylate cyclase. The aim of this study was to analyse the influence of TGFbeta1 on the functional activity of thyrocytes in suspension culture, independent of follicle disruption. In this system, we demonstrate that TGFbeta1 inhibits expression of thyroperoxidase, NADPH oxidase activity, iodine uptake and, consequently, iodine organification. Moreover, TGFbeta1 decreases basal and TSH-stimulated cAMP production and TSH receptor expression. Taken together, these data converge to demonstrate an essential role of TGFbeta1 in the regulation of the thyroid cell function.

Animals↗
PubMed2002

[Persistent sciatic artery: findings using spiral-CT].

Persistent sciatic artery (PSA), a rare anatomical anomaly, results from lack of regression of the embryonic dorsal axial artery combined with a poorly developed superficial femoral artery. The authors report the case of a 68-year old man presenting with subacute ischemia of the right lower limb. Arteriography showed complete bilateral persistent sciatic arteries. CT scan with 3D reconstructions was helpful to demonstrate the PSA descending along the back of the thigh and to exclude an aneurysmal complication.

Aged↗
PubMed2001

Pectin secretion and distribution in the anther during pollen development in Lilium.

Using the monoclonal antibodies JIM 5 and 7, pectin was immunolocalized and quantitatively assayed in three anther compartments of Lilium hybrida during pollen development. Pectin levels in both the anther wall and the loculus increased following meiosis, were maximal during the early microspore stages and declined during the remainder of pollen ontogenesis. In the microspores/pollen grains, pectin was detectable at low levels during the microspore stages but accumulated significantly during pollen maturation. During early microspore vacuolation, esterified pectin epitopes were detected both in the tapetum cytoplasm and vacuoles. In the anther loculus, the same epitopes were located simultaneously in undulations of the plasma membrane and in the locular fluid. At the end of microspore vacuolation, esterified pectin epitopes were present within the lipids of the pollenkitt, and released in the loculus at pollen mitosis. Unesterified pectin epitopes were hardly detectable in the cytoplasm of the young microspore but were as abundant in the primexine matrix as in the loculus. During pollen maturation, both unesterified and esterified pectin labelling accumulated in the cytoplasm of the vegetative cell, concurrently with starch degradation. In the mature pollen grain, unesterified pectin epitopes were located in the proximal intine whereas esterified pectin epitopes were deposited in the distal intine. These data suggest that during early microspore development, the tapetum secretes pectin, which is transferred to the primexine matrix via the locular fluid. Further, pectin is demonstrated to constitute a significant component of the pollen carbohydrate reserves in the mature grain of Lilium.

Antibodies, Monoclonal↗
PubMed2000

Rapid timing of transitions in inter-reinforcement interval duration in infants.

Infants trained on FI schedules are able to adjust their post-reinforcement pause, but many sessions at a given parameter value are necessary before the FI cumulative record appears stable. We analysed transitions from one FI value to another from our earlier experiments. Infants were exposed to FI schedules from 10 to 80 s. Under these schedules, they showed long post-reinforcement pauses with most intervals involving the emission of a single, reinforced response. The passage from one FI value to another was unpredictable for infants. We observed rapid timing effects during transitions (passage from one FI value to another, from FI 10 s to FI 20 s, etc.). Wait times increased during the first session of the new FI value, and accurate adjustments of wait times quickly appeared. Dynamic effects observed were similar to those obtained from animals in experiments on rapid-timing effects.

Journal Article↗
PubMed1997

Association of private isolation rooms with ventilator-associated Acinetobacter baumanii pneumonia in a surgical intensive-care unit.

OBJECTIVE: To determine the rates and routes of Acinetobacter baumanii colonization and pneumonia among ventilated patients in a surgical intensive-care unit (SICU) before and after architectural modifications. DESIGN: A nonsequential study comparing two groups of patients. All isolates from systematic and clinical samples were genotyped by pulsed-field gel electrophoresis (PFGE). Records of patients hospitalized during the first and second periods were reviewed and findings were compared. Between the two periods, the SICU was remodeled from enclosed isolation rooms and open rooms to only enclosed isolation rooms with handwashing facilities in each room. SETTING AND PATIENTS: All patients hospitalized and mechanically ventilated for more than 48 hours in the 15-bed SICU of the University Hospital of Besançon (France). RESULTS: For the first and second periods, the rates of colonization were, respectively, 28.1% and 5.0% of patients (P < 10(-7); relative risk [RR], 2.23; 95% confidence interval [CI95], 1.8-2.75) and the specific rates of bronchopulmonary (BP) colonization were, respectively, 9.1 and 0.5 per 1,000 days of mechanical ventilation (P < 10(-5). Seven major PFGE isolate types were identified, 4 of which were isolated from 44 of the 47 colonized or infected patients. Logistic regression analysis showed that colonization was not associated with patient characteristics. CONCLUSION: Conversion from open rooms to isolation rooms may help control nosocomial BP tract acquisition of A baumanii in mechanically ventilated patients hospitalized in an SICU.

Acinetobacter↗
PubMed1997

Novel transferable beta-lactam resistance with cephalosporinase characteristics in Salmonella enteritidis.

An isolate of Salmonella enteritidis was found to produce a plasmid-encoded beta-lactamase (DHA-1) that conferred resistance to extended-spectrum cephalosporins and cephamycins. The substrate and inhibition profiles of this enzyme resemble a class C beta-lactamase. This is the first report of a plasmid-mediated cephalosporinase of this class in the Salmonella genus.

Anti-Bacterial Agents↗
PubMed1996

A plasmocyte selective monoclonal antibody (B-B4) recognizes syndecan-1.

We developed a new monoclonal antibody. B-B4, which specifically identifies human plasma cells. It strongly reacts with all multiple myeloma cell lines and with malignant plasma cells of all tumour samples of the multiple myeloma patients tested. B-B4 does not react with any peripheral blood, bone marrow or tonsil cells. Cloning of the B-B4 antigen reveals that the monoclonal antibody recognizes syndecan-1. It appears that the monoclonal antibody B-B4 is a suitable marker for human plasmocyte identification among haemopoietic cells and a useful probe for the diagnosis of haematological malignancies. Furthermore, this monoclonal antibody can be used for depletions prior to CD34 grafting.

Antibodies, Monoclonal↗
PubMed1995

Interleukin-6 signal transducer gp130 has specific binding sites for different cytokines as determined by antagonistic and agonistic anti-gp130 monoclonal antibodies.

The cytokines interleukin (IL)-6, IL-11, ciliary neurotrophic factor (CNTF), leukemia inhibitor factor (LIF), oncostatin M (OSM) and probably the recently cloned cytokine cardiotrophin-1, signal, in combination with their specific receptors, through the common signal transducer gp130. Here, we report that the signaling activities of IL-6, IL-11, CNTF and OSM/LIF can be specifically blocked by different anti-gp130 monoclonal antibodies (mAb). Furthermore, we found two mAb, B-P8 and B-S12, which directly activate gp130 independently of the presence of cytokines or their receptors. This agonistic activity includes induction of cytokine-dependent cell proliferation and stimulation of acute-phase protein synthesis in liver cells. Compared to B-P8 mAb, the B-S12 mAb exhibited the strongest agonistic activity, while both mAb are synergistic in their action. This activity could not be blocked by inhibiting mAb against IL-6 and the IL-6 receptor. In contrast to F(ab')2 of B-S12 which still could activate gp130, Fab fragments completely lost their agonistic activity. Activation by tyrosine phosphorylation of the transcription factors Stat1 and APRF/Stat3 was also induced by B-S12 and B-P8, suggesting that both mAb induce homodimerization of gp130. Since hematopoietic stem cells express gp130 on their plasma membrane, it was anticipated that the agonistic anti-gp130 mAb could stimulate the proliferation of these stem cells. Indeed, B-S12 and B-P8 were able to stimulate CD34+ cells. In summary, our data show for the first time that mAb against gp130 can specifically block the action of distinct IL-6-type cytokines that signal through gp130. Such mAb might be of great value for therapeutic applications in diseases where a single cytokine action needs to be inhibited. In addition, the agonistic gp130 mAb may be used as growth factors for maintenance and expansion of stem cells prior to grafting.

Animals↗
PubMed1994

[Gastroesophageal reflux. Comparison of clinical, pH-metric and manometric results of Nissen's and of Toupet's procedures].

OBJECTIVES: The aim of this prospective study was to evaluate and to compare the results of the circular fundoplication (Nissen) and the posterior hemifundoplication (Toupet) for the treatment of gastro-oesophageal reflux. METHODS: For each of the 71 included patients (Nissen, n:43; Toupet, n:28) the following data were collected: surgical complications, clinical symptoms, pH-metric and manometric data, before and 4 and 28 months after operation. RESULTS: Rates of perioperative complications were 26% and 7% in the Nissen and Toupet groups respectively. The Nissen induced more late complications (14%) than the Toupet (0%). At early postoperative evaluation (mean follow-up: 4 months), the rates of clinical and pH-metric recurrences were 2% and 2.5% respectively in the Nissen group and 4% and 9% in the Toupet group (NS). Thirty-seven percent of the patients in the Nissen group and 38% in the Toupet group experienced dysphagia (NS). Disturbances in oesophageal motility, which were present in both groups before surgery, were not significantly modified. At the late evaluation (mean follow-up 28 months), some symptoms of reflux were present in 8% and 17% of patients of the Nissen and Toupet groups respectively (NS). The pH-metric recurrence rate was 10% versus 44% in the Nissen and Toupet groups respectively (P < 0.01). Dysphagia was present in 39% of patients in the Nissen group versus 13% in the Toupet group (P < 0.02). Oesophageal motility remained unchanged in the Nissen group whereas it was significantly improved in the Toupet group where the peristaltic velocity rose from 3.2 cm/s before surgery to 4.4 cm/s after (P < 0.05), giving a value comparable to that of controls (4.2 cm/s). CONCLUSIONS: These results suggest that the short term effectiveness of both procedures is comparable. The effectiveness of the Nissen is more durable, but its morbidity is higher than for the Toupet. Moreover, oesophageal motility is significantly improved by the latter.

Adult↗
PubMed1992

[Diffusion of amikacin into the sinuses in patients with nosocomial sinusitis. Administration of a single dose per day].

Twenty mechanically ventilated patients with nosocomial sinusitis were treated with amikacin 15 mg/kg administered either once a day (group 1 patients) or twice a day (group 2 patients). Amikacin was assayed in serum and in the liquid drained from the sinuses 8 times over a 24 hours' period (group 1) or 7 times over a 12 hours' period (group 2). The amikacin concentration peak was 10.9 mg/l in group 1 and 5.1 mg/l in group 2. It is concluded that amikacin can be used to treat patients with nosocomial sinusitis. High amikacin concentrations are reached with the once a day dosage.

Adult↗
PubMed1990

Treatment of corticosteroid resistant acute graft-versus-host disease by in vivo administration of anti-interleukin-2 receptor monoclonal antibody (B-B10)

In a multicenter pilot study, 32 patients showing steroid-resistant acute graft-versus-host disease (GVHD) were treated by in vivo administration of anti-interleukin-2 (IL-2) receptor monoclonal antibody (MoAb B-B10). Twenty-three patients received marrow from HLA-matched related donors, four from matched unrelated donors and five from partially matched related donors. The overall grade of GVHD was II in 16 patients, III in two, and IV in five. Five milligrams of B-B10 MoAb was infused in bolus daily for 10 days and then every second day for a further 10 days in an attempt to reduce GVHD recurrence. No clinical side effects were noted during the B-B10 treatment period. A complete response (CR) acute GVHD was achieved in 21 patients (65.6%). Six patients (18.7%) showed partial improvement (PR) and 5 patients (15.6%) no response (NR). A significant factor associated with GVHD response was the delay between the onset of the GVHD and the first day of B-B10 infusion. The earlier B-B10 was introduced, the greater the probability of CR (P = .03). There was no correlation between the serum B-B10 level and GVHD response (P = .69). There was, however, a significant correlation between the clinical response and the B-B10 kinetics as a function of time: serum B-B10 levels attained a plateau level more rapidly in the CR group than in the PR/NR group. Among the 26 complete and partial evaluable responders, GVHD recurred in 10 cases (38.4%). Host anti-B-B10 MoAb immune response occurred in only one (7.1%) of the 14 patients analyzed. Fourteen of the 32 patients (43.7%) are currently alive between 2 and 14 months after GVHD treatment with B-B10 was completed.

Adolescent↗
PubMed1990

Extrinsic compression of the renal artery by diaphragmatic crus.

Extrinsic compression of the renal artery due to a fibromuscular band originating from the diaphragm was encountered in a 26-year-old patient who had systemic hypertension associated with stenosis and kinking of one of her renal arteries. After surgical decompression, the renal artery assumed a normal expansion with disappearance of hypertension. Six other cases of extrinsic compression of the renal artery have been found in the literature. Surgical treatment is mandatory in all cases because the mechanism that causes the lesion makes percutaneous transluminal angioplasty illusory.

Adult↗
PubMed1990

[Acute necrotizing hemorrhagic pancreatitis].

There is no etiologic treatment for acute necrotizing pancreatitis. Advances in intensive care resulted in a reduction in early death rate by a better control of systemic complications. Delayed death rate from infection is high (20-60%). Diagnostic problems are an important cause, in spite of the aid of computed tomography and echography. The prognosis will further be improved by earlier diagnosis, a better definition of surgical treatment when complications arise, and constant medicosurgical collaboration.

Acute Disease↗
PubMed1990

Transluminal angioplasty performed by the surgeon in lower limb arterial occlusive disease: one hundred fifty cases.

From February 1985 through November 1988, we performed 159 transluminal angioplasty in 135 patients with arterial occlusive disease of the lower limb. The indications were claudication, 114 cases (72%) and limb salvage, 45 cases (28%). Lesions consisted of one or more critical stenoses in 142 cases (61 iliac, 69 femoropopliteal, and 12 following surgical revascularization) and single segmental occlusion in 17 cases (one iliac and 16 femoropopliteal). Angioplasty failed because the guidewire could not be inserted in nine (5.7%) cases. Angioplasty was performed intraoperatively in 44 (29%) cases and as an isolated procedure in 106 cases (71%). When performed as an isolated procedure, the percutaneous approach was preferred in 34 of the iliac lesions (73%), 28 of the femoropopliteal lesions (50%), and four of the postsurgical lesions (50%). Early postoperative mortality was 3.3% (five patients). Eight early occlusions (5.3%) were observed, two after iliac and six after femoropopliteal angioplasty. Secondary clinical surveillance and hemodynamic and venous digital angiographic follow-up detected 35 instances of stenosis (25%), 18 of which were equal to or greater than 60%. Nine occlusions occurred (6.5%), six after iliac angioplasty and three after femoropopliteal angioplasty. At 24 months, primary cumulative patency of all transluminal angioplasties was 84% and secondary patency was 89%. Transluminal angioplasty performed by the surgeon in the operating room provides good results whether performed as an isolated procedure or as a complement to surgery. The study of secondary deteriorations confirms the value of morphologic surveillance by arteriograms. Arteriography appears to be of paramount importance in the evaluation of results and the codification of indications.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗