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Biomedical subjects

A N'Diaye

Publications and source records attributed to A N'Diaye.

13 recordsLinked to original sources
PubMed2003

Comparative study of the lubricant performance of Compritol 888 ATO either used by blending or by hot melt coating.

Compritol 888 ATO is used as a lubricant in oral solid dosage formulations. It can also be used as a hot melt coating agent sprayed onto a powder. In this study, we compare the lubricant performance of Compritol 888 ATO either used by classical blending or by hot melt coating onto Lactopress by compression tests. In physical mix, the Compritol concentration does not affect the compressibility. The same compressibility is obtained with lactose coated by 0.5 or 1% of Compritol, but a higher compressibility can be observed with 2 and 3%. Cohesiveness of lactose depends on the process: hot melt coating induces a decrease of tablet tensile strength. In terms of forces transmission during compression phase and axial ejection pressures, Compritol used by hot melt coating allows for a concentration of 0.5% to directly obtain the lubricant performance of 3% of Compritol used by blending. These results suggest that the hot melt coating process induces an homogeneous repartition of the lubricant on the lactose surface, contrary to classical blending procedure. Thus, lubrication by hot melt coating seems to be a very efficient procedure. It could be used specifically for large surface area particulate systems producing a lot of friction.

Administration, Oral↗
PubMed2003

Comparative study of the lubricant performance of Compritol HD5 ATO and Compritol 888 ATO: effect of polyethylene glycol behenate on lubricant capacity.

The aim of this paper is to study the lubricant capacity of Compritol HD5 ATO, a glyceryl and polyethylene glycol dibehenate, obtained by atomization. This material is compared to Compritol 888 ATO, constituted only by glyceryl dibehenate. First, this study verifies that Compritol HD5 ATO and Compritol 888 ATO present the same granular characteristics and that their mixes with Lactopress present no structural differences. Secondly, in term of compressibility and cohesiveness, the use of Compritol 888 ATO or Compritol HD5 ATO with Lactopress does not involve any significant modification. Finally, the minor difference of lubricant capacity between Compritol HD5 ATO and Compritol 888 ATO has no consequence in compression practice. The presence of polyethylene glycol behenate does not decrease the glyceryl dibehenate compression functionality. This study concludes that Compritol HD5 ATO could be a very interesting excipient because it associates the glyceryl dibehenate lubricant capacity with the polyethylene glycol behenate-specific capacity in terms of dissolution enhancement.

Chemistry, Pharmaceutical↗
PubMed2001

Stimulation of 5-HT2 receptors in the nucleus tractus solitarius enhances NMDA receptor-mediated reflex-evoked bradycardiac responses in the rat.

The modulation by 5-HT2 receptors in the nucleus tractus solitarius of the reflex bradycardia evoked by stimulation of peripheral baroreceptors and cardiopulmonary chemoreceptors, and their possible functional interactions with local NMDA receptors, were investigated in pentobarbital- and urethane-anaesthetized rats, respectively. Microinjection of the 5-HT2 receptor agonist, 2,5-dimethoxy-4-iodoamphetamine (0.1-0.5 pmol), into the nucleus tractus solitarius elicited a dose-dependent hypotension and bradycardia. Bilateral microinjections at the same site of a subthreshold dose of 2,5-dimethoxy-4-iodoamphetamine (0.05 pmol) significantly enhanced the aforementioned reflex-evoked bradycardiac responses. In contrast, local bilateral microinjections of the NMDA receptor antagonist, 2-amino-5-phosphonopentanoic acid (500 and 1000 pmol), reduced, in a dose-dependent manner, both reflex-evoked responses. The facilitatory effect of 2,5-dimethoxy-4-iodoamphetamine upon these reflex-evoked bradycardiac responses was prevented by prior local microinjection of low doses of either the selective 5-HT2 receptor antagonist, ketanserin (10 pmol), or 2-amino-5-phosphonopentanoic acid (100 pmol), which, on their own, did not affect the reflex-associated bradycardia. These data suggest that 5-HT2 receptors within the nucleus tractus solitarius participate in a facilitatory modulation of the reflex control of heart rate, probably through functional interactions with local NMDA receptors.

2-Amino-5-phosphonovalerate↗
PubMed2000

Bradycardic responses to microinjection of N-methyl-D-aspartate into the nucleus tractus solitarius are inhibited by local activation of 5-HT(3) receptors.

Previous reports have described that glutamate ionotropic receptors in the nucleus tractus solitarius (NTS) are involved in the reflex control of heart rate, and that such a control can be inhibited by NTS-5-HT(3) receptor stimulation. In the present study, we examined in urethane anaesthetized rats the effects of intra-NTS microinjection of 1-(m-chlorophenyl)-biguanide (CPBG), a potent and selective 5-HT(3) receptor agonist, on the cardiovascular responses to local administration of glutamate ionotropic receptor agonists. Intra-NTS microinjection of CPBG reduced the atropine-sensitive bradycardia elicited by local microinjection of NMDA without affecting the cardiovascular responses to intra-NTS microinjections of AMPA or kainic acid. The reduction by CPBG of the NMDA-evoked cardiac response was blocked by prior intra-NTS microinjection of granisetron, a 5-HT(3) receptor antagonist, as well as bicuculline, a GABA(A) receptor antagonist. These results suggest that the stimulation of NTS 5-HT(3) receptors specifically reduces, via a GABA-dependent mechanism, the cardiac response to local NMDA administration.

Animals↗
PubMed1999

Locating the center of rotation of the hip.

In prosthetic surgery of the hip joint it is essential to recenter the hip to recreate the leverage of the gluteus medius muscle. Determination of the center of rotation of the hip is difficult if both hip joints have been destroyed. On the basis of 70 frontal radiographs of the hip in the standing position, the authors measured the position of the center of the femoral head in relation to Köhler's line and the TD line joining the two radiological Us ("tear-drops"). On the same radiograph they defined the horizontal and vertical indices. The descriptive analysis of these parameters stresses the influence of sex on the coordinates of the center of rotation of the hip. The authors demonstrated the statistical correlations between the coordinates of this center of rotation of the joint and certain horizontal and vertical indices. It emerged that knowledge of these indices suffices to define the theoretic position of the center of rotation. The method is compared with other principles set out in the literature. The procedure has a clinical application in the context of preoperative planning of prosthetic reconstruction of the acetabulum, whenever it is destroyed bilaterally (after trauma, in congenital dislocation or acetabular loosening, etc).

Adult↗
PubMed1998

[Resistance of the the coraco-clavicular ligaments to traction: clinical application].

One method for treating chronic incapacitating acromioclavicular dislocation is to resect the external extremity of the clavicle and to stabilise the stump by ligamentoplastic procedures, using the coracoclavicular ligament. The purpose of this work was to evaluate the mechanical quality of the ligamentoplastic approach. Twelve fresh cadavers, average age 80 years, were studied. The samples taken were 24 coracoclavicular ligaments, 24 coraco-acromial ligaments, 9 tendons from the palmaris longus muscle and 9 iliotibial tracts. The ligaments removed were tested in a Instron traction machine at a speed of 10 cm/mn. The mechanical properties of the coracoclavicular and coraco-acromial ligaments were studied. For comparison, those of the tendon of the palmaris longus muscle and the iliotibial tract were also studied. The results show the pre-rupture resistance of the coraco-acromial ligament to be 50% lower than that of the trapezoid and conoid parts of the coracoclavicular ligaments taken together. These results suggest the validity of ligamentoplastic treatment using the coraco-acromial ligament, but that reinforcement, using a tendon from the palmaris longus muscle or a piece of the iliotibial tract, may also be necessary, especially for subjects taking part in sports or with well-developed musculature.

Acromioclavicular Joint↗
PubMed1993

[Radiculo-medullary arteries of vertebral origin. Various anatomic aspects from 30 injections-dissections].

Among medullary arteries we have only examined those directly arising from the vertebral artery at the cervical level. This study is about thirty anatomical samples of cervical spine removed during necropsies; there are treated by injection-dissection method. The observed variations do not allow isolation of any artery for the cervical bulge, as possible most frequently at the lumbar bulge level. We observed variations as sometimes alternate pedicles right or left, as sometimes a symmetrical aspect finishing at the same medullar level. By injecting differently colored liquids, in the right and in the left, a side prevalence has sometimes been noted but real conclusions cannot be draw without isobar and simultaneous injections.

Adult↗
PubMed1991

Trypanosomiasis in different breeds of cattle from Benin.

Blood of different breeds of cattle, namely Lagune from the Atlantic province, Borgou and Borgou x Zebu from the Borgou province, and Somba and Zebu from the Atacora province of Benin, were examined for trypanosome infection. Thick and thin blood smears for trypanosomes, the card agglutination test (CATT), indirect immunofluorescent antibody test (IFAT) and trypanolytic test for antibodies to trypanosomes were used. Trypanosomes were detected in 19.3% (range 9.8-31.4%) of animals by examination of blood smears; antibodies to trypanosomes were found in 89.8% (range 88.4-100%) of samples by IFAT, 50.6% (range 34-87.5%) by CATT and 3.4% (range 1.1-7.1%) by trypanolytic test. Trypanosoma vivax and Trypanosoma congolense were the main species in Benin with a low number of Trypanosoma brucei. Zebu had lower infection rates than trypanotolerant breeds of Benin. The infection rates of various trypanotolerant breeds were not significantly different.

Agglutination Tests↗
PubMed1985

Soil amoebas as biological markers to estimate the quality of swimming pool waters.

The legal biological survey of swimming pool waters is based on both the level of bacteriological contamination and the amount of material of fecal origin. The great number of soil amoebas and the occasional epidemiological risk involved led us to consider using these organisms as possible biological markers to estimate the quality of pool water and the extent of disinfection. During a 1-year survey of 54 public swimming pools, 765 superficial pool and tap water samples were collected. One portion (50 ml) drawn from 1-liter samples was filtered and cultured for amoebas. In specimens considered contaminated we detected at least 20 amoebas per liter, whereas uncontaminated samples contained fewer than 20 amoebas per liter. By keeping the threshold value voluntarily low, we were able to compare tap water with pool water and to monitor the quality of various disinfection procedures (i.e., chlorine, bromine, and Cu-Ag). The data suggest that the filters were not always protective against a high concentration of amoebas. Furthermore, these disinfection procedures were not equally efficient according to estimates based on biological criteria. In addition, the quality of swimming pool water also depends on the quality of its source tap water. Thus, the numeration of soil amoebas can be used as an additional biological marker to estimate the quality of swimming pool water.

Amoeba↗
PubMed1981

Comparative study of the distribution of fuzzy coat, lectin receptors, and intramembrane particles of the ciliary membrane.

Cilia from seminal vesicles of Discoglossus (Anura, Amphibia) are partially covered with a fuzzy coat easily stained by the PATAg technique. The freeze-fractures of the ciliary membrane show large intramembrane particles (IMPs) not randomly distributed. At the base of the cilium, 3 or 4 rows of large IMPs form the ciliary necklace. Above the necklace, a 0.1 micrometer high region is devoid of particles after which the shaft membrane exhibits large IMPs coarsely lined up in 9 longitudinal rows 0.6 micrometer in height. Smaller IMPs appear randomly dispersed. The fuzzy coat is well developed in regions possessing large IMPs: the necklace region and the basal portion of the shaft. Between the necklace and the shaft, the region lacking in IMPs is also devoid of fuzzy coat. The distribution of Con A receptors is similar to that of large IMPs and to that of filaments in the fuzzy coat. On the contrary, wheat germ agglutinin (WGA) receptors are randomly distributed all along the ciliary membrane. Finally, the relationships between fuzzy coat, lectin receptors, IMPs and fibrillar links between plasma membrane and microtubules of the axoneme are illustrated.

Animals↗