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Search Results: 1 - 10 of 10866 matches for " Pierre Kamtchouing "
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The antihyperglycemic effect of Bridelia ndellensis ethanol extract and its fractions is mediated by an insulinotropic action  [PDF]
Selestin Dongmo Sokeng, Begum Rokeya, Jamadder Mohammed Abdul Hannan, Liaquat Ali, Pierre Kamtchouing
Journal of Diabetes Mellitus (JDM) , 2013, DOI: 10.4236/jdm.2013.33016
Abstract:

Backgroung: Bridelia ndellensis (Euphorbiaceae) is used as a traditional plant treatment of diabetes. The aim of the present study was to investigate the mechanism involved in the antihyperglycemic effects of this plant. Methods: An intestinal perfusion technique was used to study the effect of the ethanol extract of B. ndellensis on the intestinal absorption of glucose in normal rats fasted for 36 h. The effect of the extract (50 and 100 mg/kg) on Insulin secretion was evaluated using BRIN-BD11 pancreatic cells. Results: In a perfused rat intestinal preparation in situ, the plant extract at a concentration of 5 mg/ml did not show any inhibitory effects on glucose absorption when compared with control animals. Ouabain which is an inhibitor of glucose transport across the small intestine significantly (p < 0.001) decreased the glucose absorption during the whole perfusion period compared with the control group. On the other hand, the plant extract inhibited the gastrointestinal motility induced by Barium sulphate milk in rats. The ethanol extract of B. ndellensis at concentrations of 50 and100mg/ml stimulated in a concentration-dependent manner the insulin secretion from BRIN-BD11 cells in vitro. The induction of insulin release was significantly different when compared to control with the concentration of 100 μg/ml (P < 0.001). Alanine (10 mM) used as positive control, significantly (p < 0.001) stimulated insulin release from BRIN-BD11 cells. Conclusion: The present study has revealed that

In Vitro Evaluation of Sida pilosa Retz (Malvaceae) Aqueous Extract and Derived Fractions on Schistosoma mansoni  [PDF]
Hermine Boukeng Jatsa, Cintia Aparecida de Jesus Pereira, Ana Bárbara Dias Pereira, Deborah Aparecida Negr?o-Corrêa, Fern?o Castro Braga, Glauber Meireles Maciel, Rachel Oliviera Castilho, Pierre Kamtchouing, Mauro Martins Teixeira
Pharmacology & Pharmacy (PP) , 2015, DOI: 10.4236/pp.2015.68039
Abstract: Sida pilosa Retz. (Malvaceae) is a medicinal plant used in Africa for the treatment of dysmenorrhea, lower abdominal pains and intestinal helminthiasis. S. pilosa aqueous extract and derived fractions were investigated for their bioactivity against Schistosoma mansoni. The aqueous extract from S. pilosa aerial parts (1.25 - 40 mg/mL) and derived fractions (n-hexane, DCM, EtOAc and n-BuOH: 0.25 - 8 mg/mL) were tested on adult S. mansoni maintained in a GMEN culture medium. Praziquantel was used as the reference drug. After 24 h of incubation, worms were monitored for their viability and egg output. The antioxidant activity of S. pilosa was evaluated by the ability to scavenge the 2,2-diphenyl-1-picrylhydrazyl free radicals. The chemical composition of the n-BuOH fraction was investigated by HPLC-MS analysis. S. pilosa aqueous extract and fractions significantly increased worm mortality in a concentration-dependent manner. The n-BuOH fraction was the most active with a LC50 of 1.25 mg/mL. Significant reduction of motor activity (25% to 100%) was recorded for surviving worms incubated in different concentrations of the extract and fractions. Incubation of S. mansoni in different concentrations of S. pilosa extract and fractions led to significant reduction of egg laying (52% to 100%). The aqueous extract and derived fractions exhibited antioxidant activity in a concentration-dependent manner. The highest antioxidant activity was found with the EtOAc fraction, followed by the DCM and n-BuOH fractions. HPLC-MS analysis of the n-butanol fraction revealed the presence of two indoloquinoline alkaloids. This study disclosed the schistosomicidal activity of the n-butanol fraction from S. pilosa aqueous extract. This activity is probably related to the indoloquinoline alkaloids identified in the fraction.
Endothelium/Nitric Oxide Mediates the Vasorelaxant and Antihypertensive Effects of the Aqueous Extract from the Stem Bark of Mammea africana Sabine (Guttiferae)
Elvine Pami Nguelefack-Mbuyo,Alain Bertrand Dongmo,Télesphore Beno t Nguelefack,Albert Kamanyi,Pierre Kamtchouing,Théophile Dimo
Evidence-Based Complementary and Alternative Medicine , 2012, DOI: 10.1155/2012/961741
Abstract: This study evaluates the vasorelaxant and antihypertensive effects of the aqueous extract from the stem bark of M. africana (AEMA). AEMA was tested in vitro on intact or endothelium-denuded rats’ aorta rings precontracted with KCl or norepinephrine in absence or in presence of L-NAME or glibenclamide. The effect of a single concentration (300 μg/mL) of AEMA was also examined on the concentration-response curve of KCl. In vivo, the antihypertensive effects of AEMA (200 mg/kg/day) were evaluated in male Wistar rats treated with L-NAME (40 mg/kg/day) for 4 weeks. AEMA relaxed aorta rings precontracted with NE or KCl with respective EC50 values of 0.36 μg/mL and 197.60 μg/mL. The destruction of endothelium or pretreatment of aorta rings with L-NAME shifted the EC50 of AEMA from 0.36 μg/mL to 40.65 μg/mL and 20.20 μg/mL, respectively. The vasorelaxant activity of M. africana was significantly inhibited in presence of glibenclamide. AEMA also significantly inhibited the concentration-response curve of KCl. Administered orally, AEMA induced acute and chronic antihypertensive effects and normalized renal NO level. These results show that the vasorelaxant activity of AEMA might be mediated by the activation of the NO-cGMP-ATP-dependent potassium channels pathway and might predominantly account for its antihypertensive effect.
Effets de la substitution par l'arachide fourragère (Arachis glabrata) de l'herbe à éléphant (Pennisetum purpurum) sur le nombre d'ovulations et les mortalités prénatales chez le cobaye (Cavia porcellus L.) adulte
Kenfack, A.,Tchoumboué, J.,Kamtchouing, P.,Ngoula, F.
Tropicultura , 2006,
Abstract: Effects of Arachis glabrata Substitution to Pennisetum purpurum on the Ovulations'Number and the Prenatal Mortalities in Adult Guinea-pig Cavia porcellus L. In order to study the effects of Pennisetum purpurum substitution by Arachis glabrata on the ovulations' number and the prenatal mortalities in guinea-pigs, 36 animals including 30 females and 6 males were divided into 3 identical groups. To each group were randomly allotted one of the three diets characterised by its substitution level. The number of ovulation (2.20 ± 0.30), identical between the two rations with less legumes forage has been higher compared to the diet containing the greatest quantity of legume (2.00 ± 0.40). Only the group of guinea-pigs fed with a ration including the second highest level of forage legume recorded one prenatal mortality, which represented 4.20% of formed zygotes.
Effect of the aqueous extract of dry fruits of Piper guineense on the reproductive function of adult male rats
Mbongue F,Kamtchouing P,Essame O,Yewah P
Indian Journal of Pharmacology , 2005,
Abstract: OBJECTIVE: To study the effect of the aqueous extract of Piper guineense (Piperaceae) on male reproductive function in Wistar rats. MATERIALS AND METHODS: Male rats, 3 months old, weighing 180-210 g were administered (by gastric intubation) the aqueous extract of dry fruits of Piper guineense at two doses, 122.5 and 245 mg/kg for 8 days and 122.5 mg/kg for 55 days. The control group received distilled water for the same duration. Animals were sacrificed and the blood, testes, epididymis, seminal vesicles and prostate were collected for biochemical analyses. RESULTS: There was a significant increase in the level of testosterone in the serum and testes, cholesterol in the testes, α-glucosidase in the epididymis and fructose in the seminal vesicles after 8 days of treatment, while with 55 days of treatment, the levels of cholesterol in the testes increased by 75%, while the levels of α-glucosidase in the epididymis and the seminal vesicle fructose decreased by 24 and 21% respectively. On the other hand, there was a 20% reduction of fertility in the P. guineense-treated rats after 55 days of treatment. CONCLUSION: The aqueous extract of P. guineense at both doses (122.5 and 245 mg/kg) had a positive impact on the male reproductive function since it stimulated the secretions of the testes, epididymis and seminal vesicles. The use of P. guineense could negatively influence male fertility.
Bending Fuchsian representations of fundamental groups of cusped surfaces in PU(2,1)
Pierre Will
Mathematics , 2011,
Abstract: We describe a family of representations of $\pi_1(\Sigma)$ in PU(2,1), where $\Sigma$ is a hyperbolic Riemann surface with at least one deleted point. This family is obtained by a bending process associated to an ideal triangulation of $\Sigma$. We give an explicit description of this family by describing a coordinates system in the spirit of shear coordinates on the Teichm\"uller space. We identify within this family new examples of discrete, faithful and type-preserving representations of $\pi_1(\Sigma)$. In turn, we obtain a 1-parameter family of embeddings of the Teichm\"uller space of $\Sigma$ in the PU(2,1)-representation variety of $\pi_1(\Sigma)$. These results generalise to arbitrary $\Sigma$ the results obtained in a previous paper for the 1-punctured torus.
Two Generator groups acting on the complex hyperbolic plane
Pierre Will
Mathematics , 2015,
Abstract: This is an expository article about groups generated by two isometries of the complex hyperbolic plane.
How to Introduce the Cyclic Group and Its Properties Representation with Matlab ? Thanks to Magic Using the Perfect Faro Shuffle  [PDF]
Pierre Schott
Creative Education (CE) , 2011, DOI: 10.4236/ce.2011.21005
Abstract: Why use Magic for teaching arithmetic and geometric suit, additive groups, and algorithmic notions through Matlab? Magicians know that, once the surprise has worn off, the audience will seek to understand how the trick works. The aim of every teacher is to interest their students, and a magic trick will lead them to ask how? And why? And how can I create one myself? In this article we consider a project I presented in 2009. I summarize the project scope, the students' theoretical studies, their approach to this problem and their computer realizations. I conclude using the mathematical complement as well as weak and strong points of this approach. Whatever the student's professional ambitions, they will be able to see the impact that originality and creativity have when combined with an interest in one's work. The students know how to “perform” a magic trick for their family and friends, a trick that they will be able to explain and so enjoy a certain amount of success. Sharing a mathematical / informatics demonstration is not easy and that they do so means that they will have worked on understood and are capable of explaining this knowledge. Isn't this the aim of all teaching?
Pedestrian Analysis of Harmonic Plane Wave Propagation in 1D-Periodic Media  [PDF]
Pierre Hillion
Journal of Modern Physics (JMP) , 2011, DOI: 10.4236/jmp.2011.24027
Abstract: The propagation of TE, TM harmonic plane waves impinging on a periodic multilayer film made of a stack of slabs with the same thickness but with alternate constant permittivity is analyzed. To tackle this problem, the same analysis is first performed on only one slab for harmonic plane waves, solutions of the wave equa- tion. The results obtained in this case are generalized to the stack, taking into account the boundary condi- tions generated at both ends of each slab by the jumps of permittivity. Differential electromagnetic forms are used to get the solutions of Maxwell’s equations.
Wave Propagation in Nanocomposite Materials  [PDF]
Pierre Hillion
Journal of Electromagnetic Analysis and Applications (JEMAA) , 2010, DOI: 10.4236/jemaa.2010.27053
Abstract: Electromagnetic wave propagation is first analyzed in a composite material mde of chiral nano-inclusions embedded in a dielectric, with the help of Maxwell-Garnett formula for permittivity and permeability and its reciprocal for chirality. Then, this composite material appears as an homo-geneous isotropic chiral medium which may be described by the Post constitutive relations. We analyze the propagation of an harmonic plane wave in such a medium and we show that two different modes can propagate. We also discuss harmonic plane wave scattering on a semi-infinite chiral composite medium. Then, still in the frame of Maxwell-Garnett theory, the propagation of TE and TM fields is investigated in a periodic material made of nano dots immersed in a dielectric. The periodic fields are solutions of a Mathieu equation and such a material behaves as a diffraction grating.
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