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A Haddad

Publications and source records attributed to A Haddad.

At least 19 recordsLinked to original sources
PubMed2003

A direct contact between astrocyte and vitreous body is possible in the rabbit eye due to discontinuities in the basement membrane of the retinal inner limiting membrane.

Different from most mammalian species, the optic nerve of the rabbit eye is initially formed inside the retina where myelination of the axons of the ganglion cells starts and vascularization occurs. Astrocytes are confined to these regions. The aforementioned nerve fibers known as medullated nerve fibers form two bundles that may be identified with the naked eye. The blood vessels run on the inner surface of these nerve fiber bundles (epivascularization) and, accordingly, the accompanying astrocytes lie mostly facing the vitreous body from which they are separated only by the inner limiting membrane of the retina. The arrangement of the astrocytes around blood vessels leads to the formation of structures known as glial tufts. Fragments (N = 3) or whole pieces (N = 3) of the medullated nerve fiber region of three-month-old male rabbits (Orictolagus cuniculus) were fixed in glutaraldehyde followed by osmium tetroxide, and their thin sections were examined with a transmission electron microscope. Randomly located discontinuities (up to a few micrometers long) of the basement membrane of the inner limiting membrane of the retina were observed in the glial tufts. As a consequence, a direct contact between the astrocyte plasma membrane and vitreous elements was demonstrated, making possible functional interactions such as macromolecular exchanges between this glial cell type and the components of the vitreous body.

Animals↗
PubMed2003

[Verrucous carcinoma of the tongue occurring on lesions of lichen planus].

BACKGROUND: Verrucous carcinoma of the oral cavity is a rare entity that was formerly controversial. Etiopathogenesis remains unclear, notably as for its possible association with lichen planus. We report a case of verrucous carcinoma occurring in lesions of lichen planus of the tongue. CASE REPORT: A 78-year old, non smoking patient, with past history of cutaneous lichen planus presented for lesions of oral lichen planus affecting both the tongue and the palate. A treatment by topical tretinoin improved him in a spectacular way and brought about a remission which lasted 5 years. A recurrence occurred when the treatment was stopped; new whitish, warty cauliflower-like lesions appeared on the tongue. A biopsy confirmed the clinical suspicion of verrucous carcinoma. A laser resection was performed. Three months later, another recurrence was observed. A chemotherapy associating isotretinoin and methotrexate eliminated all lesions. The patient's condition is considered stable, under treatment, one year later. DISCUSSION: Verrucous carcinoma is a rare slow-growing oral tumor that is chiefly exophytic and does not metastasize, but it can invade and destroy oral tissues. Its clinical presentation contrasts with benign histologic features: papillomatosis, acanthosis, dysplasia in variable degrees. The occurrence on lesions of lichen planus, although "classic", is very rarely found in the literature. The treatment is not well codified. An additional chemotherapy seems necessary to prevent recurrences.

Aged↗
PubMed2002

[Subcranial subfrontal approach for the treatment of extensive cerebrospinal fluid leaks].

BACKGROUND AND PURPOSE: Over the time, the management of cerebrospinal fluid (CSF) rhinorrhea has been a major surgical challenge. In this paper, we will describe our experience using the extended anterior subcranial approach for the repair of extensive or previously treated CSF leaks. This approach consists of a nasoorbitofrontal bony flap, then an ethmoidectomy and sphenoidectomy are performed and the empty space is filled with subcutaneous fat, a pediculated periostal flap is dissected and layed extradurally at the base of the anterior cranial fossa. METHODS: Between January 1994 and December 1999, we reviewed the charts of 7 men and 3 women with a mean age of 36.5 years. The etiology was traumatic in 8 cases. One patient had a spontaneous CSF leak, the other had a macroprolactinoma. RESULTS: The average duration of surgery was 5 hours. Patients were kept in the Intensive Care unit for an average period of 36 hours. The mean follow-up period was 30 months. The success rate was 100%. Postoperatively, all of our patients were anosmic, four of them had anosmia as a preoperative finding. Cosmetically, the skin incisions are limited to the bicoronal incision. CONCLUSION: Knowing that the classical subfrontal and endoscopic approaches have their definite indications, our experience with the extended anterior subfrontal approach in the treatment of extensive or multiple anterior fossa defects suggests that it is a reliable procedure, giving an excellent access with low morbidity, provided that the patients are selected properly.

Adipose Tissue↗
PubMed2001

A practical method for the radioisotope labeling of rabbit astrocytes with (3)H-thymidine.

A practical method for the radioisotope labeling aimed at the study of the proliferative behavior of astrocytes was described. It consisted in injecting 20 microCi of (3)H-thymidine into the vitreous body and tracing by autoradiography labeled astrocytes located both inside and outside the retina, e.g. optic nerve and neighboring parts of the central nervous system. The paraffin sections were immunostained for glial fibrillary acidic protein (GFAP) previous to autoradiographic processing. The semiquantitative analysis of labeled astrocytes was carried out on autoradiographs of semithin sections of rabbits killed as early as 6 h and as late as 3 months after the single intravitreal injection of (3)H-thymidine. Compared with the technique of labeling astrocytes by systemic administration (single injection or continuous infusion) of (3)H-thymidine into small animals, the method described herein has the following outstanding features: (i) it is much more economical in terms of the amount of labeled precursor used per animal; (ii) the labeling of the astrocytes is obtained as early as 6 h and remains up to 3 months after injection; (iii) the immunolabeling of the astrocytes is compatible with autoradiography; (iv) it is less risky to the experimental animal and to the environment; (v) it can be used in animals much larger than rats or mice.

Animals↗
PubMed2001

M cell-targeted DNA vaccination.

DNA immunization, although attractive, is poor for inducing mucosal immunity, thus limiting its protective value against most infectious agents. To surmount this shortcoming, we devised a method for mucosal transgene vaccination by using an M cell ligand to direct the DNA vaccine to mucosal inductive tissues and the respiratory epithelium. This ligand, reovirus protein final sigma1, when conjugated to polylysine (PL), can bind the apical surface of M cells from nasal-associated lymphoid tissues. Intranasal immunizations with protein final sigma1-PL-DNA complexes produced antigen-specific serum IgG and prolonged mucosal IgA, as well as enhanced cell-mediated immunity, made evident by elevated pulmonary cytotoxic T lymphocyte responses. Therefore, targeted transgene vaccination represents an approach for enabling DNA vaccination of the mucosa.

Animals↗
PubMed2001

Immunohistochemistry in association with scanning electron microscopy for the morphological characterization and location of astrocytes of the rabbit retina.

The purpose of the present investigation was to establish a method for the morphological characterization and location of the several types of astrocytes in the rabbit retina. Whole retinas were incubated with unlabeled antibody to glial fibrillary acidic protein (GFAP) and, afterwards, treated with secondary antibody labeled according to the requirements for the visualization of the antigen-antibody reaction either with the confocal or transmission electron microscope. Specimens treated similarly to the latter were osmium enhanced and analyzed with scanning electron microscopy (SEM). The different immunohistochemical approaches led to the conclusion that the cells selectively visualized with the SEM are astrocytes. The higher resolution and depth of focus of this instrument allowed a better morphological characterization and a more precise location of the astrocytes in the several levels of the inner portion of the rabbit retina. The method described herein, in which pre-embedding immunohistochemistry for GFAP on rabbit retinas was associated with osmium enhancement and examination with SEM, proved to be reliable and efficient for the morphological characterization and location of astrocytes.

Animals↗
PubMed2001

An extensive system of extravascular smooth muscle cells exists in the choroid of the rabbit eye.

We investigated the structural organization of the choroid especially with regard to the presence of extravascular smooth muscle (EVSM) cells in albino rabbits. The eyes were fixed by intracardiac perfusion and processed for light, confocal, and electron microscopy. An unlabeled monoclonal antibody against alpha-actin of smooth muscle and a horseradish-peroxidase-conjugated secondary antibody were used for immunodetection of smooth muscle actin by light microscopy. For confocal microscopy, whole mount choroids were immunostained with a fluorescein isothiocyanate-conjugated (FITC) antibody. Our investigations revealed that the choroidal vessels are enveloped by bundles of EVSM. In contrast to the circular orientation of the smooth muscle cells of the tunica media of the choroidal vessels, the cells of the EVSM system were oriented longitudinally along the external surface of the vessel wall. The EVSM cells were strongly immunopositive for smooth muscle alpha-actin and exhibited a green fluorescence of the FITC-labeled anti-alpha-actin antibody. Individual cells were elongated and spindle-shaped, had the usual ultrastructural features of smooth muscle cells and, in places, were organized as 20 layers. EVSM cells were present throughout the thickness of the choroid, but not between the fenestrated endothelial lining of the choriocapillaris and Bruch's membrane, and extended from the optic nerve to the ciliary body where they merged with the ciliary muscles. Based on the three dimensional organization, immunoreactivity, and cellular and subcellular features of the EVSM system as well as information in the literature, we hypothesize that, functionally, this system, in conjunction with the choroidal vasculature, contributes to the myogenic control of choroidal blood flow and tissue volume, and also affects the intraocular pressure as well as the refractive and accommodative state of the eye.

Actins↗
PubMed2001

[Hydatid cyst of the heart simulating coronary ischemia].

Cardiac echinococcosis is rare despite endemic occurrence of echinococcosis in some regions of the world. Clinical presentation can vary and may be misleading. Diagnosis is facilitated by new imaging techniques. Surgery is mandatory to avoid serious complications. We report a case of cardiac echinococcosis with pseudo, ischemic clinical and electrical presentation.

Aged↗
PubMed2001

[Application of confocal microscopy in the study of the relationships between astrocytes and blood vessels in the retina].

OBJECTIVE: To study the rabbit retina astrocytes by using immunofluorescence techniques together with the confocal microscopy. MATERIAL AND METHODS: The rabbit retinas were processed with an anti-glial fibrillary acidic protein (anti-GFAP) for astrocyte detection and with propidium lobide for nuclear staining. RESULTS: Confocal microscopy allows for three-dimensional reconstruction of astroglial cells, the performance of double staining procedures with superposition of images corresponding to each chromogen, the exchange of observation axes for each slide and finally the performance of serial optic sections that indicate the exact cell location and their relationship with adjacent structures, eliminating the background signals. CONCLUSIONS: The confocal microscopy provides detailed information about tridimensional morphology and the location of the astrocytes in the rabbit retina. The astrocytes associated with the nerve fiber bundles are located in the nerve fiber layer. The type III perivascular astrocytes are located between the intravitreous capillaries close to the internal limiting membrane of the retina. The type I perivascular astrocytes are found in the retinal face of the intravitreal capillaries, these being the neurons which are the most distant from the retina.

Animals↗
PubMed2001

[Value of endonasal endoscopic surgery in the treatment of sphenoid cerebrospinal rhinorrheas. 15 cases].

UNLABELLED: Surgical management of cerebrospinal fluid leaks (CSFL) has improved these few past years with the development of paranasal sinus surgery under optical guidance. CSFL localized in the sphenoid sinus represent only 5 to 15% of all CSFL. The authors have analyzed a serie of 15 patients having undergone surgery from 1992 to 1999 for CSFL: 10 cases followed pituitary gland surgery realized through sublabial-transsphenoidal approach, 2 cases followed head trauma, 1 case followed a secondary neurosurgical procedure following recurrence of a rathke's cleft cyst, 1 case followed medical treatment of a bulky pituitary gland adenoma and 1 case was associated to an empty sella syndrome. The surgical procedure has relied on sphenoid sinus approach through the sphenoethmoidal recess (SER) (n = 8), transethmoidal approach (TE) (n = 2) or transseptal approach (TS) (n = 7) followed by a filling of the defect by a graft of fat with biological glue (n = 17). Sometimes it was associated to a cartilagenous graft (n = 7) when there was a bone defect. The average period of hospitalisation was 5.2 days (4-21), mean follow-up was 2.9 years (6 months-7 years). RESULTS: The success rate was 80% (3 failures were observed), 2 patients underwent secondary procedures by TS approach with success. Our results combined with the literature data led us to propose an alternative surgical strategy adapted to each case. Endonasal surgery under optic guidance compared to the transrhinoseptal approach represents an attractive alternative with less undesirable iatrogenic consequences.

Adipose Tissue↗
PubMed2001

Ethics in action.

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Ethics, Nursing↗
PubMed2001

Ethics in action.

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Communication↗
PubMed2000

[Blood pressure in Guadeloupe. Analysis according to classification criteria of the 6th report of the Joint National Committee].

OBJECTIVES: To study blood pressure distribution according to the new classification criteria of the JNC VI. To study the other cardiovascular risk factors related to blood pressure stage. METHOD: A cross sectional survey was undertaken in a medical center in Guadeloupe in 1999. The study included 1016 consecutive adult subjects. Blood pressure measurements were done with an automated oscillometric method (dynamap). RESULTS: A total of 609 women and 407 men participated in the study. Hypertension (systolic blood pressure > or = 140 mmHg and/or diastolic blood pressure > or = 90 mmHg or being on antihypertensive medication) was present in 326 subjects (32.1%). Hypertension was more frequently found in men than in women (p = 0.008). Over the whole sample, 53.1% had optimal or normal blood pressure, 14.9% had high normal blood pressure, 16.1% were stage 1 hypertension and 15.9% were stage 2 or 3 hypertension or were on antihypertensive medication. Prevalence of hypercholesterolemia (total cholesterol > or = 240 mg/dl) increased significantly with increasing blood pressure in men (p = 0.002) and women (p < 0.001). Prevalence of dyslipidemia (total cholesterolemia > or = 240 mg/dl or HDL-cholesterol < 35 mg/dl or currently receiving antihyperlipidemic therapy) increased significantly with increasing blood pressure in both sex (p < 0.001). The same trend was found for prevalence of obesity (BMI (30 kg/m2) in both sex (p < 0.01). CONCLUSION: In this population with a high prevalence of hypertension, we showed that hypercholesterolemia and obesity increased significantly with increasing blood pressure. We also showed that caring for high blood pressure should be part of a global caring of the patient looking for other cardiovascular risk factors.

Adult↗
PubMed2000

Increasing drug resistance of Mycobacterium tuberculosis isolates in Ontario, Canada, 1987-1998.

We examined trends in resistance to first-line antituberculous agents for Mycobacterium tuberculosis strains isolated in Ontario, Canada from 1987 through 1998 (n=8069). The proportions resistant were as follows: isoniazid, 9.6%; rifampin, 1.9%; streptomycin, 4. 9%; ethambutol, 1.3%; and pyrazinamide, 1.7%. Resistance to isoniazid has increased markedly since 1990, whereas resistance to streptomycin, ethambutol, and pyrazinamide increased from 1997 through 1998. Resistance to both isoniazid and rifampin did not increase. The incidence of persistence and reactivation (early or late treatment failure) was 1-2 per 100 person-years (PY) in the first 7-12 months and 0.3-0.9 per 100 PY from 13 months to 5 years thereafter. For initially susceptible strains, the incidence of resistance to isoniazid was 0.11 per 100 PY and for and rifampin was 0.06 per 100 PY in the first year and negligible thereafter, with an overall risk of 0.14% for isoniazid and 0.10% for rifampin. Resistance of M. tuberculosis to antituberculous agents, and in particular to isoniazid, is a growing problem in Ontario and is higher than elsewhere in Canada.

Antitubercular Agents↗
PubMed2000

Thermally affected characterization region by Barkhausen noise.

The controlling of some industrial components require the development of new and particular nondestructive testing techniques. The testing method using Barkhausen noise (BN) is a particular one which can be applied to ferromagnetic materials. It is a magnetic nondestructive evaluation method and can provide very important information about the material structure. The aim of our work is to study the material structure using this technique to characterize the region submitted to thermal processing. Samples of steel have been heated at temperatures between 650 degrees C and 1,200 degrees C with variable parameters (time processing, maintenance time, etc.). Acoustic BN processing allows an easy interpretation of results. Micrographs of samples have been obtained to confirm the results obtained by BN.

Fourier Analysis↗
PubMed2000

Renewal of the rabbit corneal epithelium as investigated by autoradiography after intravitreal injection of 3H-thymidine.

PURPOSE: To evaluate the renewal time of the rabbit corneal epithelium and to verify whether there are differences in the rate of renewal related to the topography of the cornea. METHODS: After the intravitreal injection of 20 microBq/eye of 3H-thymidine (3H-TdR), the rabbits were killed at variable survival-time intervals (3 hours to 90 days), and their corneas were processed for autoradiography on paraffin and 0.75-microm-thick Epon sections. The frequency of labeled nuclei, per each linear millimeter of epithelium, was estimated on paraffin sections of the whole length of the cornea of rabbits killed 6 hours after injection. The activity of unbound 3H-TdR was measured in the vitreous and aqueous humor. RESULTS: The incorporation of 3H-TdR into newly synthesized DNA ceased between 1 and 2 days after the intravitreal injection. At the shortest time intervals (3 hours to 1 day), the overwhelming majority of the labeled nuclei were located in the basal stratum of the stratified squamous epithelium. Cells of the wing stratum were labeled from 3 days onward. At 14 days, labeled nuclei were visualized only in the inner portion of the surface stratum, whereas their outermost layers were labeled only at 21 days and later. Lightly labeled nuclei could still be detected in the epithelium < or = 90 days after injection. The counts of labeled nuclei did not show significant differences in their frequencies between the periphery and the center of the cornea. The existence of vascularization at the periphery of the corneal stroma and the lack of a conspicuous Bowman's layer made it difficult to characterize morphologically the rabbit limbus with the light microscope. CONCLUSION: It takes >14 days for a daughter cell to migrate from the basal stratum to the outermost layer of the epithelium. Labeled daughter cells were detected < or = 90 days in several layers of the corneal epithelium. Therefore it takes >2 weeks for the complete renewal of the epithelium. Our data suggest that the proliferative capability of the centrally located basal cells is enough to guarantee the renewal of the corneal epithelium under physiologic conditions.

Animals↗