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Biomedical subjects

A Iannaccone

Publications and source records attributed to A Iannaccone.

At least 37 records · Page 2Linked to original sources
PubMed1995

Correlation between Goldmann perimetry and maximal electroretinogram response in retinitis pigmentosa.

To evaluate the relationship between Goldmann perimetry and maximal electroretinographic responses in patients with retinitis pigmentosa, analyses were performed on 220 affected subjects and separately on two subgroups with autosomal dominant (n = 35) and autosomal recessive (n = 29) inheritance. Electroretinograms were recorded averaging 100 iterations elicited with a 20-lux/s, 0.5-Hz white flash ganzfeld stimulation. The peripheral isopters of the visual fields were delimited with I4e, IIIe and V4e targets, measured on conventional perimetry charts with a light pen and expressed in square centimeters. Unlike most previously published reports, this investigation showed a definite correlation (p = 0.0001) between maximal electroretinographic response amplitude and visual field areas. This correlation was more evident for I4e and IIIe isopters (r = 0.89 and 0.87, respectively) than for V4e isopter (r = 0.69). This phenomenon appears to be related to distortion occurring on standard isometric charts and to spatial summation effects in the peripheral field. Such correlations held for both the autosomal dominant and autosomal recessive subgroups. It appears that, if enough accuracy is provided, maximal electroretinographic responses and Goldmann visual fields are both good measures of the remaining functioning retina in nonsyndromic retinitis pigmentosa, irrespective of inheritance models and dystrophic patterns.

Adolescent↗
PubMed1994

Clinical heterogeneity of dominant optic atrophy: the contribution of visual function investigations to diagnosis.

BACKGROUND: The variability of the visual function impairment in dominant optic atrophy (DOA) makes it difficult to diagnose the disease within genealogies. Physiologic investigations were conducted on a family with DOA to evaluate methods of detecting clinical and subclinical signs in obligate heterozygotes, in order to identify affected subjects within the genealogy and to formulate the individual and reproductive risks. METHODS: Investigations included tests for color vision, contrast sensitivity function (CSF), kinetic and static computerized perimetry, transient pattern reversal visual evoked potentials (VEPs) and steady-state flash VEPs. RESULTS: Eight subjects from the pedigree were diagnosed as having DOA. Two of them were unaware of their affection, and six showed wide clinical variability. CSF paralleled the central visual impairment, but was also slightly impaired in the two unaware subjects. Static computerized perimetry disclosed mild sensitivity defects in the central visual fields in these two patients. VEPs showed heterogeneous results as well, ranging from normal findings to severely altered tracings. CONCLUSIONS: This investigation suggests that combined clinical and functional evaluation is necessary to diagnose DOA. Particularly, the combined use of computerized perimetry, CSF, and VEPs allowed the identification of cases at a subclinical stage.

Adolescent↗
PubMed1994

Low-noise electroretinogram recording techniques in retinitis pigmentosa.

The achievement of a sharp retinal signal depends on many factors, particularly the stability of the electrodes on the corneal surface, the maximal reduction of electrical and electromagnetic disturbances and the avoidance of the noise caused by events that are synchronous with the stimulation. The availability of a low-noise recording system becomes critical in the detection of the electroretinogram in patients with retinitis pigmentosa. We studied an electroretinographic recording technique specifically designed to enhance the signal-to-noise ratio in patients with retinitis pigmentosa. The main features of the method are a membrane suction pump connected to the corneal electrodes to improve contact lens stability on the corneal surface, and a differential derivation system to record the signal. One corneal electrode is used as the recording electrode, while the other, acting as the reference electrode, is covered during full-field ganzfeld stimulation. In addition, computerized averaging and signal postrecording analyses were performed on 100 iterations. The methods described here resulted in a sharp reduction in the number of undetectable electroretinograms in our case material (28.8%). This investigation demonstrates that some of the undetectable signals reported in the literature may be due to noisy recording methods rather than to actually extinguished retinal responses.

Adolescent↗
PubMed1994

Autosomal dominant simple microphthalmos.

Congenital bilateral microphthalmos is a rare malformation of the eye, which ranges from extreme to mild reduction of total axial length. Microphthalmos may occur as an isolated ocular abnormality or as part of a systemic disorder, and different classifications of the condition have been attempted. We describe a large pedigree with 14 persons in four generations affected with bilateral microphthalmos without other ocular or systemic signs. An autosomal dominant trait with complete penetrance is proposed. Five subjects underwent a complete ophthalmological evaluation. The total axial length was measured by A scan ultrasonography in all persons. Ultrasonography showed a reduction of the total axial length (range 18.4-19.7 mm) and a reduced vitreous cavity length (range 11.4-13.5 mm) in all investigated patients. All the patients had microcornea (range 8-9.7 mm). No other ocular anomalies or associated systemic malformations were found. A review of published reports also suggests that simple, partial, posterior, pure microphthalmos and nanophthalmos are similar clinical entities sharing total axial length and vitreous cavity length reduction. Therefore, the term simple microphthalmos is proposed to identify these clinical conditions.

Adult↗
PubMed1993

Electrophysiologic monitoring of diabetic retinopathy in pregnancy.

The authors studied the correlations between electroretinographic, ophthalmologic, and clinical parameters in 30 pregnant women (20 with diabetes and 10 control subjects). Diabetic patients were divided into two groups: group 1 included 11 cases of insulin-dependent diabetes (IDDM); and group 2 included 6 cases of noninsulin-dependent diabetes (NIDDM) and 3 cases of gestational diabetes (GDM). Adapto-electroretinography (AERG) was used as the main monitoring parameter, and in particular, the relationship between the cone-mediated (b1) and rod-mediated (b2) components of the b wave (b2/b1 ratio) 7 minutes after photobleaching was studied. The results indicate that the b2/b1 ratio can detect functional modifications before the onset of ophthalmoscopically detectable retinopathy. Significant statistical correlations were demonstrated both between the type of diabetes and AERG responses, and between metabolic control (HbA1c values) and AERG alterations. A higher maternofetal complication rate in those patients with severe and frequent AERG alterations during pregnancy also was found.

Adult↗
PubMed1988

Emergency treatment of the complications of giant liver hemangiomas.

The authors discuss the problems of emergency treatment of cavernous hemangiomas of the liver. Five cases were observed and treated with different techniques, ligation of the hepatic artery, excision of the mass, embolization of the hepatic artery. The results of these procedures were strongly influenced by the patient's previous state. Treatment was successful in three patients, while the procedure adopted was able to stop the hemorrage in the other two patients. The physical state was very important for the prognosis; the two patients arriving at our Institute in deep shock both died.

Abdomen, Acute↗
PubMed1983

Effects of chronic exposure to arsenate on the cardiovascular function of rats.

Cardiovascular function was studied in anaesthetised male rats which received 50 micrograms/ml of arsenic (as sodium arsenate) in deionised drinking water for 320 days. High urinary excretion of arsenic was found at the end of treatment and the metal accumulated considerably in the kidneys and liver, which both presented slight alterations. No histopathological modifications were evident in other organs. Base line blood pressure, cardiac inotropism, and chronotropism and cardiovascular reactivity to noradrenaline, acetylcholine, angiotensin II, bradykinin, histamine, and serotonin did not differ in exposed or in control animals. In the exposed group, however, there was potentiation of the effects of vascular beta-adrenoceptor stimulation and a reduction in the vascular responsiveness to angiotensin I. Chronic arsenic exposure did not affect the baroreflex sensitivity but was able to induce sympathetic hyperactivity or hypersensitivity, or both, possibly associated with an antivagal action. Our results might help to explain the cardiovascular alterations seen in people chronically exposed to high concentrations of arsenic.

Angiotensin I↗
PubMed1981

Interferences in the spectrophotometric S-diphenylcarbazide determination of environmental hexavalent chromium in a chromium and zinc plating plant.

A study on the determination of environmental hexavalent chromium [Cr(VI)] was carried out in a chromium and zinc plating plant. The atmospheric particulate was collected both on glass wool filters and with an electrostatic sampler; Cr(VI) was determined by the S-diphenylcarbazide method. The filtered and electrostatically collected Cr(VI) was extracted with both 1.4% sulfuric acid and 7% sodium carbonate. Strong interference was observed when extraction was carried out with the acid medium. Alkaline extraction permits 95 +/- 6 (+/- SD)% recovery of the total chromium and has been shown to be suitable in releasing Cr(VI). The analyses of the alkaline samples were carried out with the standard addition method to compensate for a depressive interference of 26 +/- 8 (+/- SD)%. The absorbance decrease of the Cr-S-diphenylcarbazide complex is a time function, and it should be measured within a few minutes of the reagent addition.

Air Pollutants↗