Biomedical subjects

A Bouaziz

Publications and source records attributed to A Bouaziz.

14 recordsLinked to original sources

PubMed2006

Cinnamtannin B-1 from bay wood exhibits antiapoptotic effects in human platelets.

Proanthocyanidins, such as cinnamtannin B-1, are polyphenolic compounds with antioxidant activity that induce apoptosis in a number of tumoral cells. We have now investigated the pro- or anti-apoptotic effects of cinnamtannin B-1 in human platelets. Platelet stimulation with thrombin induced cellular apoptosis, as detected by phosphatidylserine exposure and the activation of caspases-3 and -9. Pretreatment for 30 min with cinnamtannin B-1 impaired thrombin-induced apoptosis in platelets. Thrombin has been shown to induce H(2)O(2) generation in platelets, which induced similar apoptotic events than thrombin in these cells. Pretreatment with cinnamtannin B-1 reduced H(2)O(2)-induced phosphatidylserine exposure and caspase activation. Finally, platelet stimulation with thrombin induced translocation of caspases-3 and -9 to the cytoskeletal (Triton-insoluble) fraction, which is important for their activation and the development of apoptotic events. Pretreatment with cinnamtannin B-1 impaired translocation of caspases-3 and -9 to the cytoskeleton and, as a result, procaspases are accumulated in the Triton-soluble fraction. Our results provide evidence for the antiapoptotic actions of cinnamtannin B-1 in human platelets.

Anthocyanins↗

PubMed2006

Cinnamtannin B-1 from bay wood reduces abnormal intracellular Ca2+ homeostasis and platelet hyperaggregability in type 2 diabetes mellitus patients.

Type 2 diabetes mellitus induces a number of cardiovascular disorders, including platelet hyperactivity and hyperaggregability, which is associated to an increased oxidant production and abnormal cytosolic Ca2+ mobilization. In the present study, we have investigated the effect of cinnamtannin B-1 obtained from bay wood on oxidants production, Ca2+ mobilization and aggregation in platelets from type 2 diabetic donors. Pretreatment of platelets with cinnamtannin B-1 reversed the enhanced oxidants production and Ca2+ mobilization, including Ca2+ entry, evoked by thapsigargin plus ionomycin or thrombin, observed in platelets from diabetic subjects, so that in the presence of cinnamtannin B-1 Ca2+ entry was similar in platelets from healthy and diabetic subjects. In addition, cinnamtannin B-1 reduced thrombin-induced aggregation in platelets from type 2 diabetic subjects. We conclude that cinnamtannin B-1 exerts an effective antioxidant action in platelets from patients with type 2 diabetes mellitus and reverses the enhanced Ca2+ mobilization and hyperaggregability.

Anthocyanins↗

PubMed2002

[Tuberculosis in hemodialysis patients in Tunisia].

BACKGROUND: Because of the immunity depression, patients with chronic renal failure undergoing haemodialysis are at increased risk for developing infections, Mycobacterium tuberculosis (MTb) in particular. OBJECTIVE: To evaluate, in a prospective longitudinal study over 36 months period, the frequency of Tb among these patients and underline the diagnostic difficulties. PATIENTS AND METHODS: Sixty dialysis patients were interested. The Tb assessment comprised: a questionnaire, a meticulous clinical examination, a chest X-ray, a tuberculin skin testing, as well as MT bacilli screening in biological fluids. RESULTS: Tb was seen in six among dialysis patients(10%), this rate represents 15 times the general population tuberculosis incidence in our country (23/100,000). Tb has occurred early compared to the beginning of the haemodialysis. The Tb localizations were: 4 cases of extra-pulmonary tuberculosis (3 peritoneal and one ganglionic) and only 2 cases of pleuro-pulmonary localization. The positive diagnosis represents a real problem: no bacteriological confirmation in all patients and only in one, the histological diagnosis was obtained. CONCLUSION: There was a high rate of tuberculosis in our study. The prognosis appears to be closely related to therapeutic precocity, thus specific chemotherapy started sometimes without diagnostic confirmation.

Humans↗

PubMed2002

Insecticidal activity of a nonsteroidal moulting hormone agonist on mosquito larvae and effects on ecdysteroid amounts.

The secondary effects of conventional insecticides on the environment, vertebrates and beneficial organisms have caused a move to the use of more target-specific chemicals such as insect growth regulators. Halofenozide (RH-0345) is a novel nonsteroidal ecdysteroid agonist that induces a precocious and incomplete moult in several insect orders. In the present study, the insecticidal activity of a commercial formulation of halofenozide (23% EC) was evaluated at different concentrations ranging between 8 and 32 micrograms/l. Treatment was made on newly moulted fourth-instar larvae of the mosquito, Culex pipiens (Diptera: Culicidae), and mortality was scored until adult emergence. Results showed that death in the larval stage was relatively important. Moreover, treatment caused a significant reduction in the length of the larval and pupal stage. In a second series of experiments, halofenozide was tested at two doses (LC50 = 12.58 micrograms/l and LC90 = 28.58 micrograms/l) and the ecdysteroid amounts during the fourth instar were evaluated in an enzyme immunoassay. We noted that halofenozide did not shifted the moment of the single larval ecdysteroid peak, but it caused an increase of the titre values. Finally, the compound at the highest concentration was found to increase significantly the cuticle thickness recorded at day 4 following treatment.

Animals↗

PubMed1998

Direct physical factors and PGI2 and TXA2 secretions by a human endothelial cell line: in vitro investigation of pressure and shear stress applied independently or in synergy.

The direct effect of two types of mechanical stress was measured through the prostacyclin (PGI2) and thromboxane A2 (TXA2) secretions by a confluent monolayer of cells from the EA.hy926 line. Eight values of constant pressure were applied in the gas phase above the culture medium, around atmospheric pressure taken as a control (0 mm Hg), from -500 to +760 mm Hg. Three amplitudes of sinewave modulated pressure (+/- 40; +/- 80; +/- 160 mm Hg) were explored at a frequency of 1 Hz. Modulated pressure (+/- 40 mm Hg) was also applied synergetically to a shear stress generated under steady state conditions by a rectilinear laminar motion of the medium. The cells remained adherent and exhibited unchanged morphology and viability. Constant pressure or depressure increased both PGI2 and TXA2 release but to an extent depending on the pressure value. Under pressure, the PGI2/TXA2 ratio was unchanged, but was higher under depressure, compared to the control. Pressure modulation strongly stimulated the secretion of PGI2 but had no effect on TXA2. Modulation strongly increased the PGI2/TXA2 ratio to a similar extent for the three amplitudes. Pressure-shear synergy enhanced secretion of PGI2 markedly more than shear stress alone, but the level reached was similar to the one induced by pressure modulation. No cumulative effect on the secretion of PGI2 was observed, whereas TXA2 synthesis undergoes a more than cumulative effect. The PGI2/TXA2 ratio remained unchanged under shear alone or under combined shear-pressure modulation but was higher with the modulated pressure alone. These results demonstrate that pressure has an outstanding effect on secretion that may be origin to local disturbances of the vascular system, thus inducing pathologies such as thrombosis or atherosclerosis.

Air Pressure↗

PubMed1998

Influence of a constant or a modulated pressure on insulin secretion by intact murine islets of Langerhans: existence of a threshold effect.

Pressure effect on cultured islets was investigated to simulate the behavior of the endocrine pancreas when subjected to an anatomical change in its environment. Insulin secretion from islets seeded on glass was determined by radioimmunoassays after 12-h exposure to constant or sine-wave pressure perturbation, at 37 degrees C and pH 7.4, under well-defined conditions applied through the culture medium. A specially devised setup allowed control of the constant component Po, the amplitude A, and the frequency f of the pressure perturbation. Under constant conditions, three Po values (760, 760 + 110, 760 + 250 mm Hg) were explored. Under sine-wave conditions, two frequencies (f = 0.2 and 4.33 Hz) were investigated for Po = 760 + 110 mm Hg and A = 10 mm Hg, as well as three amplitude values (A = +/-10, +/-50, and +/-110 mm Hg) for Po = 760 mm Hg and f = 0.2 Hz. Constant pressure inhibits secretion, by a factor of up to 60%, as well as low frequency (also by approximately 60%). Low amplitudes enhance secretion (by 41 and 31%), whereas a higher amplitude has a marked inhibiting effect (by 70%). In all cases, no linearity was observed, showing the existence of a threshold pressure effect. These results suggest that pressure may be an important parameter in certain forms of endocrine pancreatic dysfunctions.

Animals↗

PubMed1997

Vascular endothelial cell responses to different electrically charged poly(vinylidene fluoride) supports under static and oscillating flow conditions.

We investigated the effect of electrically charged surface copolymers on endothelialization of four types of poly(vinylidene fluoride) (PVDF) copolymer surface films with different electrical characteristics. PVDF films without a surface charge, with a remanent surface (5 and 7 microC) and with piezoelectric characteristics were studied through the secretion by an endothelial cell (EC) line culture, under static and oscillating flow conditions of prostacyclin (PGI2) and thromboxane (TXA2), two metabolites which have directly opposing actions on platelet function. The surface electrical properties of PVDF are suitable for promoting cell adhesion. Secretion of thrombomodulatory mediators varied, depending on the surface electrical charge and on the molecular structure of the PVDF substrate. Under static conditions the ECs respond to the substrates by a similar increase of PGI2. Under oscillating flow conditions, the ratio of PGI2 to TXA2 is higher with the piezoelectric PVDF film. The piezoelectricity generated from shear stress along the entire length of the fibres may be appropriate in vivo to keep the [PGI2]/[TXA2] ratio at a level which could counteract the build-up of surface deposits which could be at the origin of thrombosis.

Cell Adhesion↗

PubMed1996

Morphological aspects of endothelial cells cultured in the absence of fetal calf serum under controlled electrical charges applied to the support.

The effect of constant and modulated electrical charges applied through the culture support on endothelial cell (EC) morphology was investigated. Endothelial cells tolerated electrical charges for 48 hours, in a serum-free medium. The EC had normal morphology, except at high stationary charges, for which nucleus and cell size increased. The observed cell divisions and cellular secretions indicated that the cells rapidly adapted to the imposed stresses.

Cell Adhesion↗

PubMed1995

Effect of constant and modulated electrical charges applied to the culture material on PGI2 and TXA2 secretion by endothelial cells.

Electrical stimulation of an endothelial cell culture applied through the culture support biomaterial induced strong secretion of prostaglandin I2 (PGI2) and, to a lesser extent, thromboxane A2 (TXA2), which varied with time, the sign of the stationary electrical charge and the amplitude and frequency of a superimposed sine wave. In stationary conditions, the response is more rapid at positive electrical charges (+ some tens of microC cm-2) than at negative ones (-some tens of microC cm-2). In sine wave conditions, the ratio [PGI2]/[TXA2] is strongly increased and is maximum for an amplitude of 50 mV and a frequency of 1 Hz. These results suggest that the extracellular matrix is not only involved in cellular anchoring but also participates actively in secretion of thrombomodulatory substances, an effect apparently related to the piezoelectric properties of its components.

Cell Survival↗

PubMed1994

[CHARGE association].

BACKGROUND: The spectrum of CHARGE association includes coloboma, heart disease, choanal atresia, retarded growth and development and/or CNS anomalies, genital anomalies and/or hypogonadism and ear anomalies and/or deafness. CASE REPORT: A 4 1/2 month-old boy was admitted suffering from microphthalmia. His weight was 6 kg (-1 SD), height 60 cm (-2 SD) and his head circumference was 44 cm (+ 2 SD). He had hypotonia. Examination showed low-set ears, micrognathia, coloboma, left choanal atresia and genital hypoplasia. His heart was normal. CONCLUSION: The CHARGE association must be recognized early since it may be complicated by respiratory and feeding difficulties which can be lethal.

Choanal Atresia↗

PubMed1991

[Extension to the infratemporal fossa of malignant tumors of the face].

The authors report about the experience of the N&T department of Laënnec Hospital with tumors of the upper facial structures invading the infratemporal fossa. This invasion is currently diagnosed preoperatively owing to the progress made in imaging. The involvement of the posterior wall of the sinus is the first CT sign. 45 tumors extended into the ITF, including 35 maxillary tumors. For the latter, the frequency of invasion of the ITF was of 38% for all histological types, and of 26% for epidermoid carcinomas. Trismus, the most characteristic sign, was present in 45% only of the tumors studied. Facial pain also was frequent. The prognosis of these tumors is extremely poor, as the survival rate was of 17% at 3 years, with a mean survival of 10 months. The failures of treatment were essentially local. The surgical treatment proposed associates scooping out the ITF to maxillary resection.

Carcinoma, Squamous Cell↗

PubMed1989

[Endoscopic surgery of the turbinates. Preliminary results].

Turbinate surgery has become more precise thanks to miniaturisation and improvements in optical systems, therby allowing endoscopic surgery throughout the procedure including its posterior portion. Endoscopic turbinate surgery includes surgery of the hypertrophied middle turbinate "concha bullosa" which requires diagnosis for successful treatment (septoplasty, endonasal ethmoid surgery). Endoscopy has improved inferior turbinate cauterisation which has become more complete and precise especially for the posterior portion of the turbinate. It allows the use of new techniques: the YAG laser and the CO2 laser. Endoscopy allows good control during resection of the tail of the inferior turbinate and ensures hemostasis in the event of hemorrhage occurring during this procedure.

Endoscopy↗

PubMed1989

[Failure and complications of esthetic rhinoplasty. Apropos of 30 reoperations].

Out of 150 rhinoplasties carried out over 3 years in a Surgical Department. 20% of cases had previously undergone one or several surgical procedures. Based on these cases, the authors analysed the principal factors producing failure in cosmetic rhinoplasties and proposed a preventive strategy. The osteocartilaginous dorsum and point of the nose are considered separately in this paper.

Cartilage↗

PubMedDate not supplied

[Protée syndrome associated with renal lithiasis and vesico-ureteral reflux].

BACKGROUND: Proteus syndrome is characterized by a range of various manifestations. The main ones are partial gigantism of hands and feet, nevi, hemihypertrophy, macrocephaly. Urinary tract abnormalities are exceptional. CASE REPORT: A 6 year-old boy was examined because he had presented numerous abnormalities from birth. His weight was 26 kg (+3 SD) and his height was 135 cm (+4 SD). The main abnormalities were ptosis, pterygium colli, nevi of the cervical area, plagiocephaly, frontal bossing, scoliosis, hemihypertrophy involving the skin, mucosa and bones, macrodactyly, varicose veins and lipomatosis. He underwent surgery at the age of 3 years for urinary lithiasis associated with an ureterovesical reflux on the left side, i.e. the side of hemihypertrophy. CONCLUSION: This case suggests that Proteus syndrome may be an example of ectomesodermal dysembryoplasy but it requires confirmation by a report of at least one other case of obstruction of the ureteropelvic junction on the same side as hemihypertrophy.

Abnormalities, Multiple↗