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Biomedical subjects

M T Coroneo

Publications and source records attributed to M T Coroneo.

At least 19 recordsLinked to original sources
PubMed2007

Preventing conjunctival autograft inversion in pterygium surgery.

BACKGROUND: Surgeon-dependent variables influencing pterygium surgical outcome using the conjunctival autograft technique include conjunctival retraction as a consequence of subepithelial contracting fibrous tissue, and autograft inversion causing necrosis and sloughing of the graft. METHOD: A simple and useful technique of pterygium excision is described, which helps to ensure the correct surface and linear orientations of the conjunctival autograft, and also defines the end point of adequate excision of the subepithelial connective tissue. CONCLUSION: This simple technique of defining the anterior surface and the centrifugal orientation with the letter "G" marked on the graft prevents reverse orientation of the graft.

Conjunctiva↗
PubMed2006

Lower eyelid tensometry in younger and older normal subjects.

PURPOSE: This study aimed to establish normative and repeatability data for lower eyelid tensometry (LET) using a newly developed eyelid tensometer. METHODS: In this prospective consecutive observational case series, 32 normal adult subjects, comprising 12 younger (aged 29+/-5 years, 6M:6F) and 20 older subjects (aged 74+/-6 years, 10M:10F), underwent LET. In the younger group, LET was measured for postero-anterior (PA), nasal and temporal displacement. Duplicate measurements were taken and these were repeated on a separate occasion. Associations between repeated measurements and between right and left eyes were determined and the coefficient of repeatability for PA measurements was estimated. Differences in LET between males and females were determined using ANOVA. Only PA tensions, with duplicate measurements, were assessed in the older group, and age effects were determined. RESULTS: Mean temporal tension in the younger group was 7.8+/-2.9 mN (milliNewtons)/mm, while nasal tension was 13.0+/-4.6 mN/mm and PA tension was 11.2+/-5.3 mN/mm. There was a good correlation between interoccasion PA measurements (r=0.82-0.84, P<0.005) and between the right and left eyes (r=0.48, P<0.005). The coefficient of repeatability for PA tension was 1.8 mN/mm. In the younger group, overall eyelid tension (for all directions) for males was significantly higher than for females (ANOVA, P=0.03). For measurements in older subjects on a single occasion, PA tension was 11.1+/-3.5 mN/mm and in younger subjects 12.8+/-4.2 mN/mm (P=0.22). CONCLUSIONS: LET is rapid, repeatable, feasible, and acceptable. PA tension was the most repeatable measurement. Younger males had higher eyelid tension than females, and there was no significant reduction in PA tension with age.

Adult↗
PubMed2006

Mechanosensitivity and the eye: cells coping with the pressure.

The cells of the various organ systems in humans are subject to mechanical forces to which they must respond. Here the authors review what is known of the ways in which the cells of animals, ranging from the prokaryotic to humans, sense and transduce mechanical forces to respond to such stimuli. In what way this pertains to the eye, especially with respect to axial myopia and the pressure related disease of glaucoma, is then surveyed.

Cytoskeleton↗
PubMed2005

Case-controlled clinical and histopathological study of conjunctivochalasis.

BACKGROUND/AIMS: Conjunctivochalasis, a secondary cause of the watery eye, is frequently seen in the older age group as an elevation of the bulbar conjunctiva lying along the lateral or central lower lid margin. A prospective, interventional, case-controlled clinical and histopathological study was conducted. The relevant features of 18 patients (29 eyes) who had their conjunctivochalasis resected as part of the surgical management of their watery eye syndrome were examined. In the control group, tissue was obtained from an age matched series of 24 normal subjects undergoing routine cataract surgery. METHODS: 24 controls (24 specimens) and 18 patients (29 specimens) had conjunctival strip biopsies, taken from the usual lid margin level bulbar conjunctiva in line with the inferior limbus (controls), and the clinically apparent conjunctivochalasis (patients). These were submitted for histological study. RESULTS: 23 of 24 control sections demonstrated normal conjunctival variation. Four of 29 patient specimens demonstrated a chronic non-granulomatous conjunctivitis, while three eyes of the patient group (two patients) demonstrated features of elastosis. Of the four patients who had the inflammatory infiltrates, three had functional nasolacrimal duct obstructions (FNLDOs) and one had a primary acquired nasolacrimal duct obstruction (PANDO). Of the two patients who had elastosis, one had an FNLDO and the other had normal lacrimal drainage and was Jones 1 positive. CONCLUSION: Six of 18 patients--that is, seven of 29 specimens of conjunctivochalasis demonstrated signs of elastosis or of chronic non-granulomatous inflammation. Clinically, patients had a spectrum of aetiologies of their watery eye syndrome.

Aged↗
PubMed2005

Human ganglion cells express the alpha-2 adrenergic receptor: relevance to neuroprotection.

BACKGROUND/AIM: Alpha-2alpha adrenergic receptor (alpha(2)-AR) agonists are thought to be neuroprotective, preventing retinal ganglion cell death independent of pressure reduction. Previous studies have identified alpha(2)-ARs in rat retina. The authors aimed to demonstrate the presence and localisation of alpha(2)-ARs in human and rat retina and on the rat retinal ganglion cell line, RGC-5. METHODS: Seven postmortem human and three postmortem rat eyes were paraformaldehyde fixed and frozen. RGC-5 cells were also paraformaldehyde fixed. The expression of alpha(2A)-ARs was determined by antibody immunofluorescence. RESULTS: alpha(2A)-AR expression was identified in the human retina, on ganglion cells, and cells in the inner and outer nuclear layers (INL, ONL). Differential alpha(2A)-AR staining patterns in the INL and ONL suggest a further restriction to as yet unidentified neuronal subclasses. The RGC-5 cell line also expressed alpha(2A)-ARs in undifferentiated cells and an increased expression upon fully differentiated cells. CONCLUSION: alpha(2)-AR agonists in addition to their pressure lowering effects in the eye, may act directly upon retinal neurons, including retinal ganglion cells. The presence of alpha(2)-ARs on the RGC-5 cell line allows future investigation of these possible direct effects using in vitro glaucoma model systems.

Adrenergic alpha-2 Receptor Agonists↗
PubMed2001

Clinical evaluation of twice-daily emedastine 0.05% eye drops (Emadine eye drops) versus levocabastine 0.05% eye drops in patients with allergic conjunctivitis.

PURPOSE: The efficacy and safety of emedastine 0.05% eye drops (Emadine; Alcon Laboratories, Inc, Fort Worth, Texas), a new H(1) antagonist, were studied in comparison to levocabastine 0.05% eye drops (Livostin; Janssen-Cilag N V, Berchem, Belgium) during a twice-daily treatment schedule for 6 weeks in adult and pediatric patients with seasonal allergic conjunctivitis. METHODS: In a prospective, multicenter, randomized, double-masked, parallel group study, 222 patients with allergic conjunctivitis were randomized (221 received treatment) to either emedastine or levocabastine, instilled twice daily for 6 weeks. Patient diaries were completed four times daily (before the morning and evening instillations, at noon, and in the afternoon), and clinical examinations were conducted at regular intervals. Primary efficacy variables of ocular redness and itching and secondary efficacy variables of chemosis, eyelid swelling, patient diary data, and physician's global assessment were analyzed. RESULTS: Both emedastine and levocabastine produced a statistically significant (P =.0001) reduction in itching and redness within 5 minutes of the first instillation. All signs and symptoms improved progressively over the 6-week treatment period. After 7 days of use, and throughout the remainder of the study, emedastine was statistically superior to levocabastine (P <.006) in preventing and alleviating the signs and symptoms (itching, redness, chemosis, and eyelid swelling) of allergic conjunctivitis. CONCLUSIONS: Emedastine 0.05% eye drops administered twice daily are more efficacious than levocabastine 0.05% eye drops in the prevention and treatment of the signs and symptoms of allergic conjunctivitis in adults and children of 4 years and above. Both emedastine 0.05% eye drops and levocabastine 0.05% eye drops were well tolerated.

Adolescent↗
PubMed2001

Australasian orbital and adnexal Wegener's granulomatosis.

OBJECTIVE: To report a retrospective case series of 29 Australian and New Zealand patients with orbital and adnexal Wegener's granulomatosis (WG). DESIGN: Retrospective case series. PARTICIPANTS: Twenty-nine cases of orbital and adnexal WG were identified. METHODS: A number of oculoplastic surgeons and other clinicians in Australia and New Zealand was asked about their experience with orbital and adnexal WG. Clinical data regarding these cases were conveyed by means of a questionnaire. Cases of ophthalmic WG without features of orbital or adnexal disease were excluded. MAIN OUTCOME MEASURES: Data obtained from the questionnaire includes age, gender, limited or generalized disease, antineutrophil cytoplasmic antibody (ANCA) status, symptoms and signs: nasolacrimal obstruction, sinusitis, fistula/orbital bone erosion, orbital mass/proptosis, extraocular muscle/diplopia, visual acuity reduction caused by optic nerve compression, orbital pain, lid edema/erythema, biopsy status, and treatment status. RESULTS: Twenty-nine patients with orbital and adnexal WG were identified and described. Symptoms included awareness of an orbital mass, epiphora, orbital pain and diplopia. Signs included an orbital mass or proptosis (69%), nasolacrimal duct obstruction (52%), limited ocular rotations (52%), lid erythema and edema (31%), bony destruction (21%), and reduced visual acuity (17%). Two patients had a persistent nasolacrimocanthal fistula. Cytoplasmic pattern antineutrophil cytoplasmic antibodies (c-ANCA) were present in 52% of patients, and in 9 of 10 patients with generalized disease. However, c-ANCA was positive in only 32% (6 of 19) of patients with limited WG. Perinuclear pattern antineutrophil cytoplasmic antibodies (p-ANCA) was positive in 10% of cases. CONCLUSIONS: To diagnose and treat ophthalmic WG effectively, the clinician must be aware of its protean orbital and adnexal manifestations. WG may occur with or without systemic involvement, and c-ANCA was negative in approximately half our cases. Our cases also demonstrated two orbital fistulae, an observation previously believed to be rare.

Adolescent↗
PubMed2001

Transcaruncular medial orbitotomy for stabilization of the posterior limb of the medial canthal tendon.

PURPOSE: A method to stabilize the posterior limb of the medial canthal tendon (MCT), using a transcaruncular medial orbitotomy (TMO) approach, is described in a stepwise fashion. The technique described is a modified version of procedures published by Ritleng, Crawford and Collin, and Fante and Elner METHODS: A prospective clinical evaluation of MCT stabilization via the TMO approach was undertaken in I I consecutive patients who presented with MCT laxity as one of the features of their ectropion. These cases are initially described in detail in two representative case reports, and summarized in 11 cases. The stepwise surgical approach is outlined. RESULTS: All patients had improved symptomatology in terms of epiphora and comfort. Furthermore, in all cases the lid position was improved or normalized. In four of the I cases (36%) the lower punctum did not ultimately reside in the lacrimal ake, but the punctal position was nevertheless improved and the MCT was stabilized. CONCLUSION: The TMO procedure provides both excellent MCT stabilization and adequate placement of the lower lacrimal punctum onto the globe. It does not require canalicular resection, and avoids continued anterior displacement of the medial lower lid which may occur when only the anterior limb of the MCT is addressed surgically.

Aged↗
PubMed2001

Stabilization of the posterior limb of the medial canthal tendon using biodegradable tag anchors: a cadaveric model.

PURPOSE: This study describes and tests in a cadaveric model a new method of fixation designed for potential stabilization of the posterior limb of the medial canthal tendon, using biodegradable Tag anchors. METHODS: Study of the possibility of performing surgery to repair medial ectropion using biodegradable polyglyconate Tag anchors was commenced in the sheep cadaveric head model, and in the whole dry human skull model. This was then performed using five preserved human cadaveric whole heads, and pullout tensions were estimated in four of these. Computed tomography and magnetic resonance imaging were obtained for this model in the fifth head, and computed tomography was performed on the whole dry human skull. Dissections were carried out to establish the site of the bony defect in each of the heads. RESULTS: It was possible to obtain good Tag anchor fixation in bone overlying the maxillary and ethmoidal sinuses of the sheep, and in a young human skull. It was also possible to place adequately the anchor in the medial wall of the orbit close to the posterior lacrimal crest in all cases in the human cadaveric model. Pullout strengths were evaluated and found to range from 3.5 N to 12.4 N (mean, 7.5 N). Computed tomography and magnetic resonance imaging failed to demonstrate the biodegradable anchors in both the dry human whole skull and in the fifth cadaveric head, but did demonstrate the bony defects in the medial orbital walls through which the anchor passed. CONCLUSIONS: We have shown, for the first time, the stability of biodegradable Tag anchor fixation in a human cadaveric head model using pullout tensions and dissection studies. This method would allow adequate strength and stability to provide for control of fixation of the medial end of the lower eyelid in patients with medial ectropion and medial canthal tendon laxity.

Absorbable Implants↗
PubMed2001

Active matrilysin (MMP-7) in human pterygia: potential role in angiogenesis.

PURPOSE: Pterygia are invasive, proliferative fibrovascular growths, with the matrix metalloproteinase (MMP) family of enzymes strongly implicated in the pathogenesis of these lesions. The purpose of this study was to determine the cellular distribution and activation status of matrilysin (MMP-7) in pterygia. METHODS: Resected pterygia (n = 8) and normal conjunctiva (n = 8) were sectioned and analyzed immunohistochemically with two different epitope-specific anti-MMP-7 monoclonal antibodies (Abs) which differentiate pro- and active MMP-7. The specificity of each Ab was confirmed by Western blot analysis of p-aminophenylmercuric acetate (APMA)-activated and latent recombinant MMP-7. Pterygia (n = 4) and autologous normal conjunctiva (n = 4) were placed in organ culture to determine the activation status of secreted MMP-7. RESULTS: Precursor and active forms of MMP-7 were detected in epithelial cells from both pterygia and normal conjunctiva. Intense immunoreactivity for pro- and active MMP-7 was also observed in the pterygium vasculature, but was essentially absent from conjunctival vessels. Pro-MMP-7 was also identified in the epithelial basement membrane and associated with matrix components in pterygia. The 141-7B2 Ab reacted with the 30-kDa latent MMP-7, and the IM47L Ab precipitated a 19-kDa active enzyme, thus confirming the differential specificity of each Ab. Pro- and active MMP-7 were increased 1.4- and 2.7-fold, respectively, in the supernatants from organ-cultured pterygia compared with conjunctiva. CONCLUSIONS: This study is the first to specifically localize an active MMP species in pterygia and strengthens the hypothesis that these enzymes are involved in the pathogenesis of this disease. The data also suggest that MMP-7 may play a significant role in the angiogenesis that characterizes this lesion. Future studies will be directed at determining whether targeting MMP activity may be useful for treatment of pterygia.

Adult↗
PubMed2000

Pressure related apoptosis in neuronal cell lines.

Pressure is a crucial component of the cellular environment, and can lead to pathology if it varies beyond its normal range. The increased intra-ocular pressures in acute glaucoma are associated with the loss of neurons by apoptosis. Little is known regarding the interaction between pressure and apoptosis at the level of the cell. The model developed in this study examines the effects of elevated ambient hydrostatic pressure directly upon cultured neuronal lines. Conditions were selected to be within physiological limits: 100 mmHg over and above atmospheric pressure for a period of 2 hr, as seen clinically in acute glaucoma. This system can be used to investigate pressure relatively independently of other variables. Neuronal cell line cultures (B35 and PC12) were subjected to pressure conditions in specially designed pressure chambers. Controls were treated identically, except for the application of pressure, and positive controls were treated with a known apoptotic stimulus. Apoptosis was detected by cell morphology changes and by 2 specific apoptotic markers: TUNEL (Terminal transferase dUTP Nick-End Labeling) and Annexin V. These fluorescent markers were detected and quantified by automated Laser Scanning Cytometry. All techniques showed that increased pressure was associated with a greater level of apoptosis compared to equivalent controls. Our results suggest that pressure alone may act as a stimulus for apoptosis in neuronal cell cultures. This raises the possibility of a more direct relationship at the cellular level between pressure and neuronal loss.

Acute Disease↗
PubMed2000

Temporal and spatial growth patterns in the normal and cataractous human lens.

This study presents a computational model of the growth of the normal human lens and the induction of spoke-like cortical cataract in the aging lens. The anterior lens is modelled as a 2-D disk with a circumferential germinative zone. Lens cortical fibre cells in the same generation cover the surface in three identical 120 deg growth wedge-shaped sectors, with centre cardinal fibres at the 90, 210 and 330 deg meridians. In the foetal lens all primary fibre cells begin to elongate simultaneously. Anterior migration is spatially asynchronous, where the centre fibre begins to move towards the anterior pole first. The fibres at the end of the sector move last in the anterior direction. Fibre elongation advanced at constant speed until the boundary of the sector is reached. Spatio-temporal asynchrony and random fluctuations were increased for the adult lens. The model foetal lens evolved Y-shaped sutures anteriorly, and an inverted Y-shaped posteriorly. Fibre length varied periodically with meridional angle. The adult lens displayed irregular growth. If clusters of germinative cells are caused to opacify the resultant opacities are predominantly spoke-shaped. The model mimics crystalline lens fibre growth to the extent of successfully evolving lens sutures. Fluctuations in lens mass are consistent with an ordered pattern of growth. Lens senescence includes a progressive loss of spatio-temporal synchrony in fibre migration from the germinative zone. Peripheral light focusing by the anterior eye is a possible explanation for the nasal predilection and cuneiform shape of age-related cortical cataract.

Adult↗
PubMed2000

Primary phacoemulsification for uncontrolled angle-closure glaucoma.

PURPOSE: To report the results of primary phacoemulsification to treat uncontrolled angle-closure glaucoma. SETTING: Private practice and teaching hospital department. METHODS: This retrospective interventional case series assessed 3 patients having phacoemulsification and posterior chamber intraocular lens implantation for uncontrolled intraocular pressure (IOP) after acute primary angle-closure glaucoma. RESULTS: Intraocular pressure control was achieved in all patients postoperatively. CONCLUSIONS: Primary phacoemulsification with the option of future trabeculectomy should be considered in selected patients with persistent appositional angle closure and uncontrolled IOP after angle-closure glaucoma.

Adult↗
PubMed2000

The spectrum of presentation of silent sinus syndrome.

The general clinical, ophthalmologic, and radiologic features of three patients with silent sinus syndrome are presented. All three patients were treated surgically. The cases of these patients illustrate the spectrum of presentation of silent sinus syndrome, including enophthalmos, hypophthalmos, transient vertical diplopia, lid retraction, lagophthalmos, and blurred vision. All patients had sinus disease, and all patients improved after surgery using functional endoscopic sinus surgery techniques. The protean manifestations of silent sinus syndrome can be identified, thereby allowing appropriate management.

Adult↗
PubMed2000

Management of acute surgical orbital haemorrhage: an otorhinolaryngological and ophthalmological perspective.

This retrospective report describes the management and outcome of seven patients who suffered an acute surgical orbital haemorrhage (ASOH), secondary to a surgical procedure performed on either the sinuses, orbits or eyelids. All patients but one recovered their pre-operative vision. A management plan is outlined on how to assess and tackle this complication, so that the ENT surgeon may be better prepared to meet such an acute surgical emergency, should it arise.

Adult↗