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Biomedical subjects

R Forte

Publications and source records attributed to R Forte.

At least 19 recordsLinked to original sources
PubMed2006

Evaluation of peripapillary detachment in pathologic myopia with en face optical coherence tomography.

BACKGROUND: A newly recognized lesion in pathologic myopia is peripapillary detachment of the retinal pigment epithelium (RPE) and retina. Recently introduced en face optical coherence tomography (OCT) provides not only cross-sectional but also coronal scans of the retina, and allows lateral extent visualization and thickness measurement of lesions. METHODS: Three patients presenting bilateral peripapillary yellow-orange lobulated area in high myopia have been evaluated with fluorescein angiography (FA), indocyanine green angiography (ICGA), en face OCT (OCT/SLO; Ophthalmic Technologies Inc, Toronto, Canada), and Humphrey visual field analyzer. RESULTS: In all eyes, en face OCT has shown the presence of a peripapillary sub-RPE nonreflective area. The lateral extent of this area was clearly detectable and the measurement of its thickness was obtained. We detected a cleft in the RPE at one edge of the cavitation in two eyes, vascular tractions and vitreoretinal tractions in two eyes, a macular hole with posterior retinal detachment, and small areas of RPE detachment nonconnected with the peripapillary detachment in one eye. In the four eyes presenting a proper central fixation, glaucomatous visual field defects were evident. CONCLUSION: En face OCT has allowed to evaluate the thickness and the lateral extent of the peripapillary detachment. Therefore, its use could be important in determining the size and grading of these lesions at first visit, and to detect minimal changes of width and thickness during follow-up as an alternative to fluorescein angiography.

Aged↗
PubMed2006

Visualization of vitreomacular tractions with en face optical coherence tomography.

BACKGROUND: In vitreomacular traction syndrome, an incomplete vitreous detachment with persistent vitreous traction on the macula is present. This condition may determine formation of epiretinal membranes, macular puckering, macular oedema, and traction macular detachment. Recently introduced en face optical coherence tomography (OCT) provides not only longitudinal B-scan but also coronal C-scan images of the retina. METHODS: Fifteen eyes of 11 non-diabetic patients presenting vitreomacular traction syndrome have been evaluated with en face OCT (OTI, Toronto, Ontario, Canada). RESULTS: In 12 eyes, cystoid macular oedema was detectable at fundus examination and was associated with a broad-based adherence of the posterior hyaloid to the macula. In three eyes, foveal detachment appeared to be associated with focal foveal vitreoretinal traction. In all eyes, the lateral extent of the hyaloidal tractions on the macula was clearly detectable at coronal C-scan. They appeared as sigmoid hyper-reflective bands in the hyporeflective vitreous chamber. Overlay of C-scans on red-free confocal images allowed the visualization of the edges of the adherences in relation to the structures of the posterior pole. CONCLUSIONS: The C-scan images allowed clear visualization of the total extension of the posterior vitreomacular adherences and their relationships with the vascular arcades, the optic disc, and the fovea.

Adult↗
PubMed2006

[Intracorneal invasion of the ciliary body by melanoma].

The authors report a case of a slow reduction of vision in the left eye of a 69-year-old woman. The slit-lamp examination of the eye showed a vascularized achromic subconjunctival mass close to the nasal limbus, invading the inferonasal corneal quadrant. At B-scan and standardized A-scan echography, the mass was shown to be localized to the ciliary body, with characteristics of a malignant melanoma. The patient did not want to undergo conservative treatment. Therefore, enucleation was performed and light microscopy revealed a pigmented malignant melanoma of the ciliary body with extrascleral growth and infiltration of the anterior third of the corneal stroma. No alteration of Bowman's membrane was present. The corneal infiltration, limited to the anterior third of the stroma, could be due to the fact that at this level the collagen fibers are disposed less regularly than those of the posterior two-thirds, with this different disposition responsible for the weak resistance opposed to the tumoral invasion.

Aged↗
PubMed2006

[Iridoschisis and angle-closure glaucoma: a case report].

INTRODUCTION: Iridoschisis is a rare condition where a localized area of iris stroma is cleaved in two, with the anterior atrophic portion disintegrating into fibrils. It is frequently associated with angle closure glaucoma and with cataract. CASE REPORT: A 70-year-old male presented with reduction of visual acuity in the left eye. Visual acuity was 20/25 OD and 20/70 OS. He had suffered acute angle-closure glaucoma in the right eye 10 years before, treated with laser iridotomy and topical antiglaucomatous therapy. Intraocular pressure was 12 mmHg OD and 46 mmHg OS. Slit lamp biomicroscopic examination revealed bilateral shallow anterior chamber, iris atrophy, and leaf degeneration of the iris stroma. A-scan and B-scan standardized echography in both eyes showed shortening of the anterior chamber, a thickened and more anteriorly located lens, the presence of a few hyperechogeneous flocculated masses floating in the vitreous, and optic disc excavation. CONCLUSION: The mechanism by which iridoschisis causes angle closure is unclear. A pupillary block could be favored by the thickening and anteriorization of the lens and the ciliary processes. Both the presence of strings of iris stroma occluding the trabecula and pupillary block could cause an elevation in intraocular pressure.

Aged↗
PubMed2005

Echographic examination with new generation contrast agent of choroidal malignant melanomas.

PURPOSE: To determine the efficacy of echography with new generation contrast agents in visualizing vascularization of choroidal malignant melanomas. METHODS: An echographic contrast medium consisting of phospholipidic microbubbles filled with sulphur hexafluoride (Sonovue) was used to visualize microcirculation in 25 cases of choroidal lesions already diagnosed with standardized echography (21 choroidal malignant melanomas, four disciform lesions). RESULTS: In untreated malignant melanomas contrast agent echography revealed the presence of a dense microcirculation inside the mass. In one case vitreal seeding of the contrast agent was detectable before enucleation and histological examination revealed the presence of tumoral cells. In 12 cases treated with transpupillary thermotherapy, contrast agent echographic evaluation showed heavy regression of microcirculation after 1 week, confirmed in one case by histology, and a reduction of 70-80% in dimensions after 6 months (which appeared to have stabilized at subsequent examinations). In four cases treated with proton beam brachytherapy 2 years prior to our examination, contrast agent echography showed the absence of a microvascular network and the presence of large vessels and blood lakes. In four cases of disciform lesion, deep and superficial retina-associated vascularization was observed, with a weak spread of contrast agent inside the lesion. CONCLUSION: Live representation with good resolution of choroidal malignant melanoma microcirculation was obtained.

Adult↗
PubMed2003

Botulinum toxin dilution: our technique.

The optimal dilution of botulinum toxin remains a controversial matter. With the use of botulinum toxin in new and more delicate indications, dilution is the main procedure to reduce side effects. The objective of this paper is to review the literature and report our dilution method and our experience. We use either 500 U Dysport and 100 U Botox sterile vials. For facial indications we dilute them with 1 ml of sterile solution and in Dysport solution we add adrenalin with final solution 1:100.000. For platisma and dysidrosis we use more diluted solutions without adrenalin. It is very important to use a 30 U syringe to properly calibrate the low doses used. Although there is a great variation in toxin dilution used by practitioners, in our opinion this particular aspect of the technique remains very important: using low amounts of toxin in very low amounts of saline solution reduces side effects. The use of adrenalin, such as for local anesthetic solutions, needs more study but may be useful to reduce doses, to minimalize spread in nearby muscles and, in our experience, does not produce side effects.

Adrenergic Agonists↗
PubMed2003

How to avoid brow ptosis after forehead treatment with botulinum toxin.

Botulinum toxin is primarily indicated on the upper third of face. The treatment of the forehead wrinkles has a limited number of side effects, but can lead to brow ptosis. Brow ptosis appears in many studies with a frequency of around 1-5%. This is caused, often, by using incorrect injection sites, too high dosages, and by an inappropriate selection of patients. In our experience, this side effect has occurred in less than 1% of cases. This paper will emphasize the technical methods we use in order to reduce to a minimum this unpleasant side effect. Understanding the side effects of botulinum toxin on forehead requires a thorough understanding of muscular anatomy. We emphasize the importance of the correct dilution, the use of adrenalin and a 30 U syringe, particularly for patients who have skin abundance (dermatocalasys) of forehead. Patients with dermatocalasys should usually be excluded, but if treated, it should be done in two different sessions, without overdosing and respecting the symmetry. Brow ptosis, the only real side effect of forehead treatment with botulinum toxin A, can be reduced to a minimum by using simple rules.

Botulinum Toxins, Type A↗
PubMed2001

Is acetazolamide effective in the treatment of diabetic macular edema? A pilot study.

AIM: To investigate whether acetazolamide, already found to be helpful in decreasing cystoid macular edema in patients with retinitis pigmentosa, was also effective in the treatment of diabetic macular edema in nonproliferative retinopathy. METHODS: Two randomized age- and sex-matched groups (cases and controls) of 12 diabetics (five Type 1 and seven Type 2) were selected for this pilot study and graded for retinopathy (Early Treatment of Diabetic Retinopathy Study-Airlie House Classification). Cases were treated with acetazolamide for three months according to a standard protocol. The Early Treatment of Diabetic Retinopathy Study chart was used for assessing far-best corrected visual-acuity, and fluorescein angiography was performed using the Heidelberg Retina Angiograph. The Amsler grid-test and computerized-perimetry (Octopus 2000R) were also performed. RESULTS: Fluorescein-angiographic findings and perimetric data improved significantly (p < 0.01) in the acetazolamide-treated cases compared to the controls while visual-acuity varied only slightly (p > 0.01). The Amsler grid-test resulted insignificant in our study (p > 0.05). No adverse effects or significant variations in laboratory tests were recorded. CONCLUSION: Further clinical investigations involving larger numbers of patients and a longer follow-up are required to confirm these preliminary results. However, the present study seems to suggest that acetazolamide could be effective in reducing fluorescein-angiographic findings and improving perimetric data in diabetics with macular edema, even though the mechanism of action remains obscure. Visual-acuity varied only slightly.

Acetazolamide↗
PubMed2001

Fault tree analysis for exposure to refrigerants used for automotive air conditioning in the United States.

A fault tree analysis was used to estimate the number of refrigerant exposures of automotive service technicians and vehicle occupants in the United States. Exposures of service technicians can occur when service equipment or automotive air-conditioning systems leak during servicing. The number of refrigerant exposures of service technicians was estimated to be 135,000 per year. Exposures of vehicle occupants can occur when refrigerant enters passenger compartments due to sudden leaks in air-conditioning systems, leaks following servicing, or leaks caused by collisions. The total number of exposures of vehicle occupants was estimated to be 3,600 per year. The largest number of exposures of vehicle occupants was estimated for leaks caused by collisions, and the second largest number of exposures was estimated for leaks following servicing. Estimates used in the fault tree analysis were based on a survey of automotive air-conditioning service shops, the best available data from the literature, and the engineering judgement of the authors and expert reviewers from the Society of Automotive Engineers Interior Climate Control Standards Committee. Exposure concentrations and durations were estimated and compared with toxicity data for refrigerants currently used in automotive air conditioners. Uncertainty was high for the estimated numbers of exposures, exposure concentrations, and exposure durations. Uncertainty could be reduced in the future by conducting more extensive surveys, measurements of refrigerant concentrations, and exposure monitoring. Nevertheless, the analysis indicated that the risk of exposure of service technicians and vehicle occupants is significant, and it is recommended that no refrigerant that is substantially more toxic than currently available substitutes be accepted for use in vehicle air-conditioning systems, absent a means of mitigating exposure.

Air Conditioning↗
PubMed1999

Effects of a low-intensity conditioning programme on VO2max and maximal instantaneous peak power in elderly women.

The effects of 12 weeks of a low-intensity general conditioning programme on maximal instantaneous peak power (Wpeak) and maximal oxygen uptake (VO2max) were examined in 20 elderly women. After medical, familiarisation, and ethical procedures, the subjects were randomly divided into either a training and or a control group. The training group [n = 11; mean (SD) age 63.0 (3.1) years] agreed to take part in a 12-week training programme at an exercise intensity kept under 60% of the heart rate reserve for about 60 min, 3 times a week. The control group [n = 9; mean (SD) age 63.5 (3.3) years] did not perform any particular physical training. Before and after the training period, all participants underwent anthropometric measures and a maximal cycling test to exhaustion to measure their VO2max. In addition, Wpeak was determined 1 week later by the subjects performing a vertical jump from a squatting position on a force platform. Following training, neither the anthropometric characteristics nor the VO2max changed in either of the groups. In contrast, Wpeak increased significantly (P < 0.001) in the training group, but did not change in the control group. This result could be interpreted as the result of an improved level of neuromuscular activation. Furthermore, it shows that although muscle power declines with age at a faster rate than does aerobic power, its sensitivity to training seems to be higher than that of the aerobic system.

Age Factors↗
PubMed1999

The role of international environmental agreements in metered-dose inhaler technology changes.

Introduced in the 1950s, metered dose inhalers (MDIs) became a revolutionary way to deliver medication directly to the lungs of patients with asthma and chronic obstructive pulmonary disease. Since their initial introduction, MDIs have used chlorofluorocarbons to propel the medication out of the canister into a patient's lungs. This article presents an overview of the global transition away from the use of chlorofluorocarbon propellants in MDIs to non-ozone-depleting substitutes including hydrofluoroalkane (outside of the pharmaceutical industry and in the context of Montreal Protocol and Kyoto Protocol discussions, these gases are referred to as hydrofluorocarbons; hydrofluoroalkane-134a, for example, is referred to as hydrofluorocarbon-134a) propellants, in accordance with the terms of the international environmental agreement the Montreal Protocol on substances that deplete the ozone layer (the Montreal Protocol). This article will also describe the environmental characteristics of chlorofluorocarbons and hydrofluoroalkanes when they are used as MDI propellants. Finally, the article will review key provisions of the pending Kyoto Protocol to the United Nations Framework Convention on Climate Change (the Kyoto Protocol) that may affect the future of hydrofluoroalkanes.

Administration, Inhalation↗
PubMed1999

Treatment of nonproliferative diabetic retinopathy with Defibrotide in noninsulin-dependent diabetes mellitus: a pilot study.

PURPOSE: Microvascular alterations, impairment of coagulation, ischemia and diffuse endothelial damage are related to the progression of diabetic retinopathy. Defibrotide has been demonstrated to produce profibrinolytic, cytoprotective and vasofacilatory activities. The aim of the present study was to evaluate the therapeutic effect of Defibrotide in the treatment of nonproliferative diabetic retinopathy. METHODS: Two randomized age- and sex-matched groups (cases and controls) of 35 NIDDM patients presenting non-proliferative diabetic retinopathy were included in this study: cases were treated with Defibrotide (800-1600 mg daily) for two years. RESULTS: All tested parameters (ETDRS visual acuity; computerized perimetry; retinography; fluorescein angiography), improved significantly (p<0.001) in Defibrotide-treated patients compared to controls. In our opinion, Defibrotide's manifold effects on vascular endothelia may account for this improvement by stimulation of tPA, PGI2, PGE2, thrombomodulin and modulation of endothelin-1 release. CONCLUSIONS: Our preliminary data seem to suggest that Defibrotide could be proposed for medical treatment of nonproliferative diabetic retinopathy.

Aged↗
PubMed1998

Determinants of maximal instantaneous muscle power in women aged 50-75 years.

The present study aimed at analysing the age-related decline in maximal muscle power (W) in 52 sedentary healthy women aged between 50 and 75 years to determine whether force or velocity is the major determinant. Maximal muscle power was estimated from two types of vertical jumps, squatting (SJ) and countermovement (CmJ), performed on a force platform. It was obtained by measuring the vertical force (F(opt)) applied to the body centre of gravity and calculating the corresponding vertical velocity (v(opt)). An age-related decline in absolute W was statistically significant in all the conditions examined and in both peak W and average power (W) values. The decrease in v(opt) was also statistically significant. Also F(opt) declined but this reduction was not statistically significant with the exception of the average value in CmJ. Not surprisingly the highest W were obtained in CmJ, and the difference in power production between the two types of jump showed an age-related decrement only in W. The main finding of the study was the demonstration that v(opt) was the critical determinant of the age-related decline in W in healthy elderly women.

Aged↗
PubMed1996

Autosomal-dominant retinitis pigmentosa associated with an Arg-135-Trp point mutation of the rhodopsin gene. Clinical features and longitudinal observations.

PURPOSE: To report the clinical and functional characteristics of patients affected with autosomal-dominant transmitted retinitis pigmentosa (adRP) from a large Italian pedigree in which a point mutation predicting the Arg-135-Trp change of rhodopsin was identified by polymerase chain reaction-single-strand conformation polymorphism analysis. METHODS: Seven patients, ranging in age from 6 to 41 years, underwent a full clinical ophthalmologic evaluation, kinetic visual field testing, and electroretinographic testing. RESULTS: In agreement with previous reports, this rhodopsin mutation yielded a particularly severe phenotype, both clinically and functionally. The evaluation of patients from this pedigree in the first and second decade of life demonstrated that retinal function is still electroretinographically measurable at least until 18 years of age, although reduced to 2% to 4% of normal. Longitudinal measures showed that the rate of progression of the disease was unusually high, with an average 50% loss per year of electroretinographic amplitude and visual field area with respect to baseline. Later in the course of the disease, macular function is also severely compromised, leaving only residual central vision by the fourth decade of life. CONCLUSIONS: The phenotype associated with mutations in codon 135 of the rhodopsin molecule appears to have an unusually high progression rate and yields an extremely poor prognosis. These distinctive features make the Arg-135-Trp phenotype substantially different from the general RP population, and also from many of the other adRP pedigrees with known rhodopsin mutations reported to date.

Adolescent↗