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Biomedical subjects

J Feher

Publications and source records attributed to J Feher.

42 records · Page 3Linked to original sources
PubMedDate not supplied

Age-related changes in rat retina.

PURPOSE: To describe the changes in rat retina occurring with ageing by means of histological methods, scanning electron microscopic observations and morphometrical data; and to study by means of biochemical methods the amount of protein content in retinal tissues. METHODS: Samples of fresh retinal tissue obtained from young, adult, and aged rats were studied by means of traditional histological methods and by scanning electron microscopy. Particular attention was paid to morphometrical data and to the changes which occur with ageing. With the aid of a quantitative analysis of images, a large amount of morphometrical data was collected. Moreover, the amount of protein content in retinal tissues has been determined. RESULTS: Retinal thickness significantly decreases with age. The ganglion cells seem to be more vulnerable to age-related loss than other retinal cells. The number of retinal capillaries is diminished with age. The intercellular connections between photoreceptors, the number of cellular processes, and the number of synaptic bodies of the bipolar cells also decrease significantly with age. These results were all confirmed by scanning electron microscopy observations and morphometrical findings. Biochemical dosage of proteins demonstrates that retinal tissues decrease with age. CONCLUSIONS: All morphological, morphometrical, ultrastructural and biochemical data are concordant in demonstrating that the retinal tissues of rats undergo specific changes with age. Our findings are in agreement with those described by previous authors and underline that the rat retina can be considered an optimal model for studies on neuronal maturation and/or neuronal ageing. Since our data have confirmed that many changes occur in rat retina with ageing, we can hypothesize that rat retina is particularly sensitive to developmental changes and to senile decay.

Aging↗
PubMedDate not supplied

Metabolic changes in rabbit lens induced by treatment with dexamethasone.

Metabolic changes in the rabbit lens have been studied by means of nuclear magnetic resonance spectroscopy. These changes have been induced by prolonged topical treatment with dexamethasone. Our results demonstrate an increase in sorbitol, sorbitol-3-phosphate, fructose-3-phosphate, glycerol-3-phosphate and glucose-6-phosphate levels and a decrease in glutathione sulphate (GSH) and myo-inositol levels, in agreement with what was observed in lenses from streptozocin-diabetic rats before lens opacity. The hyperglycaemia can only partially explain all these observed biochemical variations. The lack of increase in the intermediates of pentose cycle, such as sedoheptulose-7-phosphate, seems to support the hypothesis of an inhibition of glucose-6-phosphate dehydrogenase by dexamethasone treatment. Finally dexamethasone treatment induces a decrease in GSH. The decreasing or the loss of GSH has been suggested as a possible pathogenic mechanism in the cataract formation.

Administration, Topical↗
PubMedDate not supplied

Mitotropic compounds for the treatment of age-related macular degeneration. The metabolic approach and a pilot study.

Recent histopathologic studies have shown that mitochondria and peroxisomes of the retinal pigment epithelium may play a central role in the pathophysiology of age-related macular degeneration (AMD). We supposed that compounds which improve mitochondrial functions (mitotropic compounds) may show beneficial effects in preventing AMD. Fourteen patients affected by early AMD were treated with a mixture containing acetyl-L-carnitine (ALC), polyunsaturated fatty acids (PUFAs), coenzyme Q10 (CoQ10) and vitamin E, while an equal number of age- and sex-matched patients affected by early AMD were treated with vitamin E only. Recovery time after macular photostress, foveal sensitivity and mean defect in the visual field as well as blood lipid levels were recorded at the beginning and after 3, 6, 9, 12 and 24 months of follow-up. In the treated group, all the visual functions showed slight improvement which was evident after 3 months of treatment and remained nearly stationary by the end of 24 months. The same tests in the control group showed slow worsening. The divergence between treated and control groups became more marked with time, but the difference was not significant at any time of the follow-up. These findings suggest that the blend of ALC, PUFA, CoQ10 and vitamin E may improve retinal functions in early AMD.

Acetylcarnitine↗
PubMedDate not supplied

Improvement of visual functions and fundus alterations in early age-related macular degeneration treated with a combination of acetyl-L-carnitine, n-3 fatty acids, and coenzyme Q10.

The aim of this randomized, double-blind, placebo-controlled clinical trial was to determine the efficacy of a combination of acetyl-L-carnitine, n-3 fatty acids, and coenzyme Q10 (Phototrop) on the visual functions and fundus alterations in early age-related macular degeneration (AMD). One hundred and six patients with a clinical diagnosis of early AMD were randomized to the treated or control groups. The primary efficacy variable was the change in the visual field mean defect (VFMD) from baseline to 12 months of treatment, with secondary efficacy parameters: visual acuity (Snellen chart and ETDRS chart), foveal sensitivity as measured by perimetry, and fundus alterations as evaluated according to the criteria of the International Classification and Grading System for AMD. The mean change in all four parameters of visual functions showed significant improvement in the treated group by the end of the study period. In addition, in the treated group only 1 out of 48 cases (2%) while in the placebo group 9 out of 53 (17%) showed clinically significant (>2.0 dB) worsening in VFMD (p = 0.006, odds ratio: 10.93). Decrease in drusen-covered area of treated eyes was also statistically significant as compared to placebo when either the most affected eyes (p = 0.045) or the less affected eyes (p = 0.017) were considered. These findings strongly suggested that an appropriate combination of compounds which affect mitochondrial lipid metabolism, may improve and subsequently stabilize visual functions, and it may also improve fundus alterations in patients affected by early AMD.

Acetylcarnitine↗