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Biomedical subjects

M R Angi

Publications and source records attributed to M R Angi.

At least 19 recordsLinked to original sources
PubMed1996

Changes in myopia, visual acuity, and psychological distress after biofeedback visual training.

The effects of auditory biofeedback training on myopia, visual acuity (VA), and psychological distress were evaluated in a controlled prospective study involving 55 mildly myopic (< or = -3.5 D) high school students. These myopes were divided into 2 groups, matched for age and dioptric defect: 33 were treated with visual training and 22 were not; 27 emmetropic subjects formed a further control group. Subjects were evaluated at the baseline (T0), at 10 weeks after the end of the treatment (T1), and after an interval of 12 months (T2) from the baseline for: (1) manifest and cycloplegic refraction, and the difference between them (cycloplegic tonus); (2) VA measured with a conventional optotype in all subjects, and also with a computer-generated optotype in the treated group; and (3) psychometric values and personality profile. At T2, myopia had significantly worsened both in the treated and in the control myopes; VA in the treated myopes appeared significantly improved when measured by the conventional optotype, but unchanged when measured by computer. Psychometric scores improved significantly in the treated myopes and in the emmetropic controls. Objectively the autorefractometer showed that 38% of the myopes had voluntary control of positive accommodation, i.e., the ability to increase spherical defect; no voluntary control of negative accommodation was observed. An increase in VA was associated with a significant increase in the foveation time (i.e., the period of time when the target is imaged on the fovea and the eye is motionless), and was partly attributable to a learning effect. In conclusion, biofeedback visual training had a positive effect on psychological distress and subjective VA improvement, but failed to reduce the existing myopia or delay its evolution.

Adolescent↗
PubMed1993

Heritability of myopic refractive errors in identical and fraternal twins.

The existence of a visual feedback control of eye growth in humans is controversial, as the contributions of genetic and environmental factors are still unknown. To evaluate the heritability of refractive defects, we measured ocular refraction in 19 monozygote and 20 dizygote twin pairs (mean age 5 years). Monozygosity was ascertained by a common chorion, similarity of somatic traits, and identical dermatogliphes and was confirmed in myopes by blood marker diagnosis. Ocular refractive defects and axial length were evaluated by cycloplegic autorefractometry and biometry. By comparing identical and fraternal twins heritability of refractive defects was estimated to be 0.08-0.14; this low value indicates that the observed variability in refractive errors is nongenetic in origin. Three monozygote pairs were anisomyopic; differences between eyes in identical twins were related to the increased axial length of myopic eyes. In one eye, myopia was attributed to visual deprivation induced by a congenital cataract, while in five eyes it was correlated directly to the degree of astigmatic defects. The discordant axial length observed in monozygote twins is nongenetic. In agreement with previous findings reported in the literature, it is proposed that visual impoverishment of retinal images may play an early regulatory role in postnatal eye growth.

Blood Grouping and Crossmatching↗
PubMed1993

The binocular videorefractoscope for visual screening in infancy.

Photorefraction is a promising technique for screening infants for amblyopiogenic defects, but currently used instruments often produce images that are difficult to interpret due to inaccurate control of the subject's fixation, to the narrow range (+/- 4 D) of the measurable error, to ill-defined crescent borders, and to chromatic aberration. A charge-coupled device (CCD) camera with near-infrared sensitivity connected to a computer with an image grabber for real-time equalization was devised to overcome the aforementioned problems. This binocular videorefractoscope (VRB) enables a dynamic and nondissociating refractive status and an ocular motility testing. Fixation and accommodative response are observed on-line and the strabismic angle is measured off-line. Arrays of infrared-emitting diodes with a variable eccentricity and position reveal sphere and/or cylinder errors (+/- 10 D; null interval, +0.00 to -2 in an 8-mm pupil diameter) as well as squint (> 5 prism diopters) and dioptric media opacities. The VRB was tested during noncycloplegic screening for amblyopiogenic defects in 212 3-year-old children. The findings were compared with the results of manifest and cycloplegic autorefractometry in a blind study. The VRB revealed a sensitivity of 81% and a specificity of 97%. In conclusion, the VRB can give a fast, noninvasive, and reliable evaluation of amblyopiogenic factors in infants.

Accommodation, Ocular↗
PubMed1992

Results of photorefractometric screening for amblyogenic defects in children aged 20 months.

This report evaluates the validity of a preventive programme in a population which underwent refractometric screening at the ages of 20 months and 4 years. In 1987, 1,046 children born in 1985 in the territory of the Veneto National Health Unit No. 19 were invited to undergo screening for amblyogenic factors such as meridional hyperopia greater than or equal to +2.50 diopters (D), myopia less than or equal to -2.50 D, anisometropia greater than or equal to 2 D, opacity of the dioptric media and strabismus. The test method was non-cycloplegic photorefractometry (PhR). Seven hundred and ninety-five children were tested (76%); positive cases underwent subsequent cycloplegic autorefractometry (AR) and corrective lenses were prescribed as necessary. In 1989, an eye test was performed on 653 children who had taken part in the previous PhR screening and on 350 similar children who had not: the test included evaluation of visual acuity, stereopsis and AR. An eye with a corrected visual acuity of less than 0.7 was considered amblyopic. PhR demonstrated a sensitivity of 80%, a specificity of 96% and a positive prediction rating of 46% in the identification of amblyogenic factors. The prevalence of amblyopia at 4 years of age in the group which had undergone previous screening was 1.07% vs. 2.57% in the group which had not (P: not significant). The progress of the myopia was studied in a group with full optical correction used continuously (Group A) and in a control group under-corrected by at least 1.5 D (Group B).(ABSTRACT TRUNCATED AT 250 WORDS)

Amblyopia↗
PubMed1990

Immunopathology of ocular sarcoidosis.

Sarcoidosis is a multisystem disease characterized by enhanced immune responses at sites of involvement. To elucidate the immunopathogenesis of ophthalmic lesions, cell infiltrates in biopsies from conjunctiva and other tissues involved (lungs, lymph nodes, skin) were studied in 26 patients with active sarcoidosis in order to define the surface phenotype and the distribution of cells in granulomatous lesions. Biopsy specimens were also stained for detection of immunoglobulins, complement and fibrinogen deposits. The data demonstrate a lymphocytes/macrophages interaction in the central core of granulomatous areas as the crucial event that initiates the maintains the state of inflammation: at all sites of disease activity is present a compartmentalization of T-cells expressing a helper-related phenotype which account for the great majority of infiltrating cells both in the early lesions (aggregate of macrophages surrounded by lymphocytic infiltrate) and in well-organized sarcoid granulomata. The presence of plasma cells and immunoglobulin deposits may represent an epiphenomenon in line with the helper infiltration, suggesting a local hyper-reactivity of the B-cells immune system. This study suggests some immunopathogenetic mechanisms leading to the formation and growth of conjunctival sarcoid granulomata.

Adolescent↗
PubMed1987

A psychosomatic approach to idiopathic recurrences of anterior uveitis.

We examined 60 patients affected by idiopathic recurrent anterior uveitis and studied the relevance of stressful life events and psychological distress in relation to relapses of the disease. The results were statistically insignificant when compared to the control groups. We found that neither life events nor psychological distress played a contributory role in this disease.

Adult↗
PubMed1986

Activated T cells with immunoregulatory functions at different sites of involvement in sarcoidosis. Phenotypic and functional evaluations.

Cells from recovered BAL fluid and from infiltrates in different involved tissues (lungs, lymph nodes, conjunctiva, liver, spleen, and skin) were studied in 22 patients with active sarcoidosis in order to define the surface phenotype, functional in vitro properties, and topographic distribution of the cells in granulomatous lesions. Our data demonstrated a compartmentalization of activated T cells with immunoregulatory functions from the blood to all sites of disease activity. In fact, these cells were found to express the T4+ Leu 8- 5/9+ T17- phenotype, which belongs to cells with helper activity, and that provide heightened responses in functional assays of helper activity, IL-2 release, and the ability to respond in AMLR's. Both a cellular redistribution and a local in vitro replication account for this tissue compartmentalization in sarcoidosis. The microanatomic location of activated T cells, as defined by immunohistological evaluation, showed that the state of activation in these T cells may be a consequence of an intimate contact between helper cells and macrophages within the sarcoidosis granulomas.

Adult↗
PubMed1985

A rapid HPLC technique for determining levels of histamine in tears from normal and inflamed human eyes.

Because of the important role of histamine in the inflammatory process, the measurement of histamine levels in tears has been considered as a possible index of eye irritancy. Histamine levels have been measured using an HPLC procedure involving fluorimetric detection after fluorescamine derivatization. Analyses, at picomole levels, were carried out in less than 5 minutes using 10 microliter of tear samples collected from either normal or inflamed human eyes.

Chromatography, High Pressure Liquid↗
PubMed1985

Asymptomatic ocular sarcoidosis.

Sarcoidosis, as multisystem disease, may affect the entire visual apparatus and its adnexa: the eye hence is an optimal observation point to confirm diagnosis and assess disease activity. However, the eyes are affected only in one-fourth of cases, and the majority of the lesions are asymptomatic, requiring appropriate examination techniques to be detected. In this paper we reviewed the ophthalmic changes found in a group of 163 Italian patients affected with sarcoidosis, comparing the data collected with those published in the literature. Conjunctival granulomata, chorio-retinal lesions and lacrimal gland involvement were the more common ocular manifestations of the sarcoidosis detected; these were asymptomatic in two patients out of three. Ocular changes in sarcoidosis are more common than generally appreciated even in white patients, but their detection requires meticulous eye examination, the use of 67 Gallium scans of the head, fluorangiography, and the yield of biopsies from available eye tissues.

Adult↗
PubMed1985

Double-pointed 30-gauge needle for keratocentesis.

A new, efficient instrument for performing keratocentesis for aqueous humour aspiration and anterior chamber microinfusion is described. It consists of a double-pointed 30-gauge needle, a liquid container (a nonflexible vinyl tube plugged at one end with a rubber stopper) and a aspiration-infusion syringe connected to the container and needle by a flexible vinyl tube. The instrument's advantages are a safer technique, complete collection of the aqueous humour and better handling of the sample.

Aqueous Humor↗
PubMed1984

Immunohistological study in sarcoidosis: evaluation at different sites of disease activity.

Sarcoidosis is a multisystem disease characterized by enhanced immune responses at sites of involvement. For this reason, an immunohistological study using monoclonal antibodies against T-cell subpopulations was carried out in order to evaluate the topographic distribution of immunocompetent cells in tissue sections obtained from a variety of involved organs, such as parenchymal lung, lymph nodes, eyes, skin, and liver. Biopsy specimens were also stained for detection of immunoglobulins, complement, and fibrinogen deposits. The data demonstrate a redistribution of T cells from the blood to all the sites of disease activity where they account for the large majority of infiltrating cells, both in the early lesions (merely a lymphocytic infiltrate) and in well-organized granulomas. Moreover, these cells express a helper-related phenotype, as demonstrated by the high Leu-3/Leu-2 ratios, at sites of involvement with respect to the blood (blood, 1.8/1; transbronchial lung biopsies, 10.5/1; lymph nodes, 19/1; skin, 28/1; liver, 22/1; eye, 14/1). In line with this helper infiltration is the presence of plasma cells and immunoglobulin deposits, suggesting a local hyperreactivity of the B-cell immune system. Both the hypergammaglobulinemia and the T lymphopenia usually observed in the blood of sarcoid patients could be explained by these observations. Comparative analysis of immunohistological data and bronchoalveolar lavage (BAL) findings provides further evidence that BAL cellularity reflects the changes already occurring in lung histology. The studies emphasize the importance that immunological phenomena play in the pathogenesis of sarcoidosis and provide new insights into the mechanisms leading to the formation and maintenance of the sarcoid granuloma.

Adult↗
PubMed1984

Evidence of cells bearing interleukin-2 receptor at sites of disease activity in sarcoid patients.

The frequency of cells reactive with anti-Tac monoclonal antibody (MoAb), which recognizes the interleukin-2 (IL-2) receptor, has been evaluated in cell suspensions from peripheral blood and bronchoalveolar lavage (BAL), and in frozen sections from involved tissues in 18 patients with active sarcoidosis. Peripheral blood lymphocytes of sarcoid patients do not bear Tac determinant and reduced numbers of Tac+ cells are inducible following PHA stimulation. On the other hand, significant numbers of lymphocytes reactive with anti-TacMoAb are present in the cells obtained from the BAL and a number of Tac+ cells infiltrate the lung, lymph node and conjunctiva. The finding of Tac+ cells in the BAL fluid and in other organs in patients with sarcoidosis provides evidence that some T cells in these involved tissues have the characteristics of IL-2 responder cells and thus the potential to absorb IL-2, supporting the hypothesis that T lymphocytes replicate in situ at sites of disease activity.

Adult↗