Biomedical subjects

E Pacella

Publications and source records attributed to E Pacella.

9 recordsLinked to original sources

PubMed2003

Age-related changes in rat optic nerve: morphological studies.

Age-related changes of the optic nerve were studied in 3-month-old (young), 12-month-old (adult) and 24-month-old (aged) male Sprague-Dawley rats. Cross sections of the intracranial portion of the optic nerves of animals of different age groups were stained with haematoxylin-eosin and examined under a light microscope at low and high magnification. Other sections were stained with crystal violet for demonstration of glial cells. A third group of sections were stained immunohistochemically to detect glial fibrillary acidic protein (GFAP) which is a marker for localizing and characterizing astrocytes. All morphological results were subjected to the quantitative analysis of images and to statistical analysis to identify significant morphometrical data. Tissue protein concentrations were determined on homogenized fragments of optic nerve. Our results demonstrate the following age-related changes: (1) increase of the optic nerve sheaths (meningeal membranes); (2) increased number of astrocytes; (3) increase of areal density of GFAP immunoreactivity; (4) increased diameter and area of the optic nerve; (5) decreased number of nerve fibres; (6) decreased-size of nerve fibres and (7) decrease of the nerve fibres/meningeal membrane ratio from 3:1 to 1:1. Moreover, the protein amount does not change with age. The rat optic nerve, therefore, appears sensitive to ageing processes and can be considered as a useful model for the studies on neuronal ageing.

Aging↗

PubMed2001

Occurrence of catecholaminergic nerve fibers in the human uveoscleral tissue in conditions of normal and raised intraocular pressure.

The distribution of catecholaminergic nerve fibers (CNF) in human uveoscleral tissue was studied in six human eyes with normal intraocular pressure and in five eyes with increased pressure. The eyes with increased pressure had no visual field alterations and the patients did not have any glaucoma-related optic neuropathies. The amount of norepinephrine in these structures was also analysed. Catecholaminergic nerve fibers were detected by means of fluorescence microscopy and were counted using the quantitative analysis of images. Our results demonstrate that the occurrence of catecholaminergic nerve fibers (expressed in Conventional Units = C.U.) in human uveoscleral tissue is 15.4 +/- 1.6 C.U. in eyes with normal intraocular pressure. In eyes with increased intraocular pressure, these values were 12.2 +/- 1.2 C.U. Moreover, the amount of norepinephrine in tissue homogenates of the same eyes was evaluated and found to be 21.7 +/- 1.3 microg/gr tissue fresh weight of the human uveoscleral tissue in eyes with normal intraocular pressure. This value decreased to 18.8 +/- 1.1 microg/gr tissue fresh weight in the same tissue in conditions of raised intraocular pressure. In these experiments, the small number of eyes examined made it difficult to draw general conclusions. However, the role of human uveoscleral tissue was emphasized by the rich catecholaminergic innervation. A decrease of catecholaminergic nerve fibers and norepinephrine occurs when intraocular pressure is elevated. The modifications of these parameters, involved in the sympathetic control of aqueous humor outflow, may support the hypothesis of a possible relevant role for the human uveoscleral tissue in different pathological conditions.

Adult↗

PubMed2000

Distribution of peptidergic nerve fibres in the guinea pig trabecular meshwork.

A quantitative analysis of peptidergic nerve fibres located in the trabecular meshwork of the guinea pig has been performed. Our results confirm that this structure contains VIP-, NPY- and substance P-like immunoreactivity as major neurotransmitters. These findings were obtained using immunohistochemical techniques. For this purpose serial sections of the eye were stained by immunohistochemistry for each of three neurotransmitters and stained sections were analysed by quantitative image analysis. Our findings demonstrate that SP-positive, NPY-positive and VIP-positive nerve fibres occupy 11.2, 4.9 and 2.4%, respectively, of the observed area (expressed as conventional units, C.U.) in the trabecular meshwork of the guinea pig eye. It is relevant to emphasize that the area containing these three types of peptidergic nerve fibres appears to be large (18.5 +/- 6.6 C.U.) in proportion to the total observed area. The innervation of the drainage angle of the guinea pig eye has been well described by many authors. This is the first study to report quantitative measurements of three types of peptidergic nerve fibres identified and measured in this area. The presence of these three neurotransmitters in the trabecular meshwork of guinea pig eye suggests their possible participation in aqueous humor regulation.

Animals↗

PubMed1999

Excimer laser photorefractive keratectomy for high myopia and myopic astigmatism.

BACKGROUND AND OBJECTIVE: To determine the efficacy, safety, and predictability of excimer laser photorefractive keratectomy of high myopia and myopic astigmatism. PATIENTS AND METHODS: 76 eyes of 52 patients with myopia from -8.00 to -23.50 diopters (D) with or without astigmatism up to -5.50D were treated with the VISX 20/20 excimer laser (VISK, Santa Clara, CA) and a multi-zone ablation technique. Visual acuity, manifest refraction, corneal haze, and topography were evaluated at 1 week and 1, 3, 6, 12, and 18 months postoperatively. RESULTS: Postoperative refractions were generally stable after 12 months. At the last follow-up all patients were within - 1.96 D of the intended correction. Eighteen months postoperatively, 68% of patients undergoing photorefractive keratectomy (PRK), and 65% of patients undergoing photo astigmatic refractive keratectomy (PARK), were within 1 D of planned refraction. Furthermore, 87% of patients after PRK and 80% of patients after PARK had a visual acuity of 20/40 or better. CONCLUSIONS: High myopia with or without astigmatism was successfully treated in most of the patients using PRK. The stability of the postoperative refraction during the first 18 months seems to be good. The incidence of adverse effects was low but improvements in the future should further reduce complications, thus increasing the safety of refractive procedures.

Adult↗

PubMed1996

Fox's modified technique using the Mersilene mesh sling in the management of blepharoptosis.

BACKGROUND AND OBJECTIVE: Frontalis suspension is the best surgical procedure for severe ptosis with poor or absent levator muscle function. In addition to autologous fascia lata, a variety of materials are available for suspension. The authors describe the use of Mersilene mesh slings developed to overcome the problems of failure, slippage, and extrusion commonly associated with various suspensory materials. PATIENTS AND METHODS: Brow suspension was performed in 20 ptotic eyelids of 14 patients. All patients had severe ptosis with levator function of 4 mm or less. The surgical technique used was a modified version of the method originally described by Fox using the Mersilene mesh sling. RESULTS: The improvement in lid height was evaluated by preoperative and postoperative vertical aperture measurements and ranged from 2 to 5 mm (average 3.5 mm). The results were maintained in all cases during a follow-up period of 18 months. CONCLUSION: The good functional and cosmetic results suggest that Fox's modified technique using the Mersilene mesh sling has a definite place in ptosis management.

Blepharoptosis↗

PubMed1990

Intraocular lens complications.

The authors implanted intraocular lenses (IOL) in 780 eyes and considered complications of this surgery, dividing the complications into intraoperative and postoperative, the latter early and late. The most frequent intraoperative complications were: hyphema, vitreous injury, pupil deformation with an IOL in the anterior chamber (AC), and hyphema and corneal lesions with an IOL in the posterior chamber (PC). Among the early postoperative complications of an IOL in the AC the authors noticed striate keratopathy and uveal flare and postoperative transitory ocular hypertension and striate keratitis with an IOL in the PC. Moreover, in late postoperative complications in AC implantation they observed: cystoid macular edema, bullous keratitis, retinal detachment, late uveitis, opacification of posterior capsule, eccentric displacement of the IOL, and less frequently, cystoid macular edema in PC implantations. The authors prefer IOL implantation in the PC after extracapsular cataract extraction, since this surgery causes less problems in the cornea, vitreous, and retina.

Anterior Chamber↗

PubMed1989

[Retinal lesions in HIV seropositive patients].

118 patients with HIV infection underwent complete ophthalmologic examination to detect the presence of any eye pathology. The study was intended to show a correlation between such pathology and the total CD4 + lymphocyte count considered to be indicative of the immunologic status. The most frequently encountered lesions were cotton-wool patches, vascular congestion, hemorrhages, chorioretinitis, segmental vasculitis and optic disc pallar. Almost all the patients with ocular manifestations, also had a CD4 + count of less than 200/mm3 which suggest that ocular lesions are of bad prognostic significance even in asymptomatic patients.

Acquired Immunodeficiency Syndrome↗

PubMedDate not supplied

A morphometric study of age changes in the rat optic nerve.

Age-related changes of the optic nerve fibres were studied in 3-month-old (young), 12-month-old (adult) and 24-month-old (aged) male Sprague-Dawley rats. The optic nerve was harvested with particular care from the intracranial portion. Cross sections from the optic nerve of animals of different age groups were stained with toluidine blue and examined under a light microscope at low and high magnification. Other sections were stained for the demonstration of glial cells using the method described by Holzer. A third group of sections were stained by the immunohistochemical method to detect glial fibrillary acidic protein, which is a marker for localising and characterising astrocytes. All these morphological results were subjected to the quantitative analysis of images and to statistical analysis of the values to identify significant morphometric data. Biochemical dosages of proteins were also performed on homogenised fragments of the optic nerve. Our results demonstrate that the following age-related changes can be observed: (1) an increase in meningeal membranes, (2) an increased number of astrocytes, (3) an increase in areal density of glial fibrillary acidic protein immunoreactivities, (4) an increased thickness of the entire optic nerve and an increased area of the nerve, (5) a decreased number of nerve fibres and (6) a decrease in the nerve fibre/meningeal membrane ratio from 3:1 to 1:1. Moreover, the amount of protein does not change with age. The rat optic nerve, therefore, appears sensitive to aging processes.

Aging↗

PubMedDate not supplied

Excimer laser photorefractive keratectomy for hyperopia.

BACKGROUND AND OBJECTIVE: Photorefractive keratectomy (PRK) has been extensively evaluated for the correction of myopia. This study was undertaken to assess the safety, efficacy, and reliability of PRK in the correction of hyperopia. PATIENTS AND METHODS: There were 28 eyes with refractions of +1 to +7.75 D treated for hyperopia with the Chiron Technolas 217-C excimer laser. Thorough visual assessments were made before treatment and at regular follow-up to 18 months. Complications and patient satisfaction were noted. RESULTS: At 18 months the mean subjective refraction was +0.46+/-1.00 D with 26 eyes (92.8%) within 1 D of emmetropia. Thirteen eyes (46.4%) achieved uncorrected visual acuity (UCVA) of 20/20 or better and all patients had an UCVA of > or = 20/32 or better. Best corrected visual acuity (BCVA) remained unchanged in 26 eyes (92.8%) and improved in 2 eyes (7.2%). On the seventh day from treatment, 17 eyes (25%) had a loss of 2 or more lines of BCVA. At 15 days this was reduced to 8 eyes (14.3%) and at one month to 3 eyes (3.6%). There were no cases of loss of 2 or more lines of BCVA at 18 months of follow-up. All patients expressed a high degree of satisfaction. CONCLUSIONS: Photorefractive keratectomy safely and effectively reduced hyperopia in the patients studied. The technique was reliable and still offered good results at 18 months of follow-up.

Adult↗