Showing papers in "Ophthalmic Research in 1984"
TL;DR: A new method to measure in vivo nuclear transmittance using scanning photometry is proposed, thus complementing its present application in measuring lens scatter and fluorescence, and a correlation of the three phenomena with each other is allowed, indicating that the loss oftransmittance of the nucleus cannot be explained by its thickening alone but that changes in its composition must take place.
Abstract: We propose a new method to measure in vivo nuclear transmittance using scanning photometry, thus complementing its present application in measuring lens scatter and fluorescence. We compared our method of measuring the transmittance with a previously reported in vivo method and found an adequate correlation. We then measured the fluorescence, scatter and transmittance of lenses without cataract and those with as much as a mild yellowing. The three phenomena correlated with age. In addition, this study allowed a correlation of the three phenomena with each other, indicating that the loss of transmittance of the nucleus cannot be explained by its thickening alone but that changes in its composition must take place. Finally, a preliminary study on diabetics showed early onset of the process responsible for the increase in lens fluorescence. This process did not seem to be accelerated in diabetics in comparison with normals. The nuclear scatter appeared to increase more rapidly with age in nondiabetics as compared to diabetics. This preliminary study suggests mainly that scanning photometry can be used to study aging and pathologic changes in the lens.
85 citations
TL;DR: The pineal organ is a derivative and integral component of the brain and has changed from a 'third eye' capable of direct achromatic and/or chromatic responses to light to an endocrine gland influenced by visual stimuli from the retina.
Abstract: The pineal organ is a derivative and integral component of the brain. In phylogeny it has changed from a 'third eye' capable of direct achromatic and/or chromatic responses to light to an endocrine gland influenced by visual stimuli from the retina. The outer segment of pineal photoreceptors contains a microspectrophotometrically detectable photopigment and an opsin-immunoreactive protein. Certain pinealocytes endowed with an outer segment display fluorophores of 5-HT/HTP and can be regarded as photoneuroendocrine cells. These photoneuroendocrine cells resemble cerebrospinal fluid-contacting neurons. The intrinsic circuitry (wiring diagram) of pineal photoreceptor organs has been only partly deciphered ; this holds true also for the neurotransmitters and synaptic patterns. Pineal photoreceptor organs are connected to the brain, i.e., to habenular, pretectal, thalamic, tegmental (reticular), and hypothalamic centers. The special anatomical and physiological features of the pineal organ enable it to translate photic information into neural and neuroendocrine responses.
43 citations
TL;DR: The experimental model proposed here provides the possibility to monitor the survival of the retina and demonstrates that ocular lipid peroxidation very notably shortens the survival time.
Abstract: The effects of membrane lipid peroxidation are determined in isolated albino rat retina. Lipoperoxidation induced by addition of Fe2+ + ascorbate to the perfusion liquid leads to an irreversible decrease of amplitude in the electroretinogram. The experimental model proposed here provides the possibility to monitor the survival of the retina and demonstrates that ocular lipid peroxidation very notably shortens the survival time. The specific role of the rod membranes for the excitation mechanism in the retina as revealed by these experiments is discussed.
38 citations
TL;DR: Results indicate that a chemical which decreases melatonin content in the eye also lowers the IOP and vice versa, and it is suggested that some melatonergic mechanism is involved in the circadian rhythm of IOP.
Abstract: It has been reported that diurnal changes in intraocular pressure (IOP) may be related to the fluctuation of melatonin levels in the eye. In order to test this hypothesis, effects of methysergide, tranylcypromine, and p-chlorophenylalanine (PCPA) on IOP recovery were studied in rabbits infused with hypertonic saline. Methysergide, a serotonin blocker at receptor sites, did not affect IOP recovery, presumably because it did not affect melatonin synthesis. Tranylcypromine, a monoamine oxidase inhibitor which preserves serotonin and eventually increases the level of melatonin in tissues, facilitated IOP recovery. PCPA, known to inhibit serotonin synthesis and to lower the melatonin level in tissues, markedly delayed IOP recovery. These results indicate that a chemical which decreases melatonin content in the eye also lowers the IOP and vice versa. It is suggested that some melatonergic mechanism is involved in the circadian rhythm of IOP.
30 citations
TL;DR: The ultrastructural study of the corneo-scleral trabeculum in steroid induced glaucoma shows a greater endothelial activity and an increase of the ground substance and of the cytoplasmic organelles, as well as a great sensitivity of theGround substance to hyaluronidase.
Abstract: The ultrastructural study of the corneo-scleral trabeculum in steroid induced glaucoma shows a greater endothelial activity and an increase of the ground substance and of the cytoplasmic organelles, as well as a great sensitivity of the ground substance to hyaluronidase. The morphometric study of the cytoplasmic organelles showed a significant difference between treated and non-treated eyes.
28 citations
TL;DR: Findings strengthen the view that the avian pineal organ has not lost its photoreceptive capacity and may establish synaptic contacts to intrapineal neurons via complex neuropil formations.
Abstract: The pineal organs of the adult domestic mallard, fowl and pigeon were investigated by means of neurohistological techniques and electron microscopy. The application of opsin immunocytochemistry to the pineal organ of the domestic mallard reveals antigenic sites in the outer segments of the pinealocytes. Avian pinealocytes may establish synaptic contacts to intrapineal neurons via complex neuropil formations. Bundles of nerve fibers resembling the pineal tract of poikilothermic vertebrates were found in the pineal stalk. These findings strengthen the view that the avian pineal organ has not lost its photoreceptive capacity.
24 citations
TL;DR: Corneal sensitivity was measured before and after exposure to an electric welding arc and the other eye serving as a control retained the same sensitivity throughout the same period of time.
Abstract: Corneal sensitivity was measured before and after exposure to an electric welding arc. The ultraviolet radiation produced in the exposed eye a rapid and large decrease in corneal sensitivity with an equally rapid recovery, all occurring within 4 h. The other eye serving as a control retained the same sensitivity throughout the same period of time.
22 citations
TL;DR: The changes observed in the ganglion cell responses after application of the drugs are discussed in light of the possible neuronal circuitry of the pineal organ.
Abstract: Extracellular recordings were performed on electrophysiologically identified achromatic neurons of the photosensitive pineal organ of the frog. The effects of iontophoretically applied aspartate and glutamate as well as one aspartate antagonist (D-α-aminoadipate) were observed on spontaneous activity and light-evoked responses of pineal neurons. Aspartate and glutamate showed a powerful excitatory effect on achromatic neurons. The effect was dose-related and reversible. D-α-Aminoadipate substantially diminished the excitatory aspartate effect. The changes observed in the ganglion cell responses after application of the drugs are discussed in light of the possible neuronal circuitry of the pineal organ.
21 citations
TL;DR: The density of stromal nerve trunks and their branches was determined at the peripheral and the central areas of the four corneal quadrants in the Long-Evans hooded rat by using a nonspecific cholines.
Abstract: The density of stromal nerve trunks and their branches was determined at the peripheral and the central areas of the four corneal quadrants in the Long-Evans hooded rat by using a nonspecific cholinesterase histochemical reaction. It was found that the density of stromal innervation is the same in the different quadrants and in the 2 eyes of the same animal. However, the density of stromal innervation was higher at the periphery that at the center of the cornea. The study provides quantitative information on the density of corneal stromal innervation in a commonly used laboratory animal. These data were unavailable in the literature, and can be used as a baseline for experimental studies.
20 citations
TL;DR: Patients with diabetes mellitus with diabetic retinopathy, open-angle glaucoma, raised intraocular pressure, and hyperviscosity of whole blood, plasma, and aqueous humor were divided by a random method into 2 equal groups and received 1,500 mg of Doxium daily for 3 months.
Abstract: 50 patients with diabetes mellitus of 2-7 years' duration were divided by a random method into 2 equal groups, one of which received 1,500 mg of Doxium (calcium dobesilate) daily for 3 months, the other group receiving a placebo. All the patients had diabetic retinopathy, open-angle glaucoma, raised intraocular pressure, and hyperviscosity of whole blood, plasma, and aqueous humor. 10 patients in each group underwent operation for glaucoma. At the end of the trial the state of the retina, the visual acuity, and the visual fields had improved, and the intraocular pressure and the 3 viscosity values had fallen to a statistically significant extent in the Doxium group compared with the initial status and with the placebo group. These results are consistent with Doxium's known action in reducing capillary fragility, microvascular hyperpermeability, and blood viscosity.
19 citations
TL;DR: The isolated retina of rabbit lies on nylon tissue fixed in a ring, which is placed in a chamber and the receptor potential is recorded extracellularly between an intraretinal microelectrode and a reference electrode at the receptor side.
Abstract: The isolated retina of rabbit lies on nylon tissue fixed in a ring, which is placed in a chamber. The lower side of the retina, by choice the receptor or ganglion cell side, is superfused by a plasma
TL;DR: The increase in collagen solubility with elevated glucose concentrations appears to be the result of the inhibition of lysyl-derived cross-link formation because of an increased nonenzymatic glycosylation of the epsilon-amino groups of lYSyl residues of newly synthesized collagen in culture.
Abstract: The effect of increasing glucose concentration on the solubility of newly synthesized collagen was studied in bovine retinal capillary pericyte (BRCP) cultures. Synchronized pericytes were labeled with [3H]-proline in media containing either 5, 10, 20 or 40 mM glucose, or 5 mM glucose and 100 μg/ml β-aminopropionitrile fumarate (BAPN). The relative rate of collagen synthesis in the medium (soluble collagen) was significantly increased, and the rate in the cell layer (insoluble collagen) was decreased, by an elevated glucose concentration. The increase in collagen solubility with 20 and 40 mM glucose (over normal, 5 mM glucose) was 14 and 42%, respectively, of that obtained with BAPN. BAPN and 4-deoxypyridoxine inhibited BRCP lysyl oxidase activity, but elevated glucose concentrations did not. Increased nonenzymatic glycosylation of newly synthesized collagen was demonstrated in BRCP cultures co-labeled with L-[14C]-glucose and L-[3H]-proline. The increase in collagen solubility with elevated glucose concentrations therefore appears to be the result of the inhibition of lysyl-derived cross-link formation because of an increased nonenzymatic glycosylation of the e-amino groups of lysyl residues of newly synthesized collagen in culture.
TL;DR: Stripe patterns of varying spatial frequency were presented in the onset-offset mode and the amplitude of the onset response showed a spatial selectivity which occurred with a high intensity at a higher spatial frequency than with a low intensity.
Abstract: Stripe patterns of varying spatial frequency were presented in the onset-offset mode. At a high contrast the amplitude of the onset response showed a spatial selectivity which occurred with a high int
TL;DR: The results indicate that prostaglandins are involved in early phase of the inflammation which can be reduced with cyclooxygenase inhibitors such as indomethacin and leukotrienes are responsible primarily in the later phase because they are suppressed by lipoxygenases such as phenidone and NDGA.
Abstract: Ocular inflammation was induced by lens protein to minic the traumatic injury of the eyes. Pretreatment of the eyes with indomethacin resulted in marked reduction of this ocular inflammation in the early phase. Pretreatment of the eyes with phenidone and nordihydroguaiaretic acid (NDGA) on the other hand reduced ocular inflammation during both early and late phases. These results indicate that prostaglandins are involved in early phase of the inflammation which can be reduced with cyclooxygenase inhibitors such as indomethacin and leukotrienes are responsible primarily in the later phase because they are suppressed by lipoxygenase inhibitors such as phenidone and NDGA. Although histamine is implicated in the process of inflammation, the H1-antagonist, pyrilamine, had very little effect on ocular inflammation, whereas the H2-antagonist, cimetidine, exhibited no effect but rather enhanced the ocular inflammatory responses at the peak of inflammation. These results are not in accord with published findings.
TL;DR: Results suggest that Stimulation of A13 cells may disinhibit ganglion cells, thus heightening their responsiveness at low levels of illumination, and AII cells appear to quicken the response time of the rod system in the mid-scotopic range.
Abstract: Signals from rod bipolar cells of cat retina are processed by a variety of rod amacrine cells before finally arriving at ganglion cells. Three of these rod amacrine cells (All, A13, and A17) have been studied at the physiological and anatomical levels; the results suggest that each carries out a unique visual function: All cells appear to quicken the response time of the rod system in the mid-scotopic range, while A17 cells may increase the light-gathering area of rod bipolars near visual threshold. Stimulation of A13 cells may disinhibit ganglion cells, thus heightening their responsiveness at low levels of illumination.
TL;DR: Treating alkali-burned corneas with ascorbic acid significantly decreases the incidence of corneal ulcerations and perforations compared to the control group that received the vehicle.
Abstract: Alkali-burned corneas were treated with 2% ascorbic acid. Topical applications and subconjunctival injections were given for 32 days. Treatment with ascorbic acid significantly decreases the incidence of corneal ulcerations and perforations compared to the control group that received the vehicle. These results confirm previous studies and strongly suggest that ascorbic acid presents a potential for use in the alkali-burned human eye
TL;DR: The ophthalmic examination of patients with hypertrophic cardiomyopathy treated with high doses of verapamil over a considerable period of time showed no evidence of a side effect of the drug, thus proving the drug is safe and effective in these patients.
Abstract: The ophthalmic examination of patients with hypertrophic cardiomyopathy treated with high doses of verapamil over a considerable period of time showed no evidence of a side effect of the drug, thus pr
TL;DR: It can be concluded that the drugs currently available are of suitable local anaesthetic effect with little influence of the vehicle or preservative agent used.
Abstract: By means of a recently developed electronical optical esthesiometer the efficacy of five different topical anaesthetics was compared. The influence of vehicle and concentration was also investigated. From the results it can be concluded that the drugs currently available are of suitable local anaesthetic effect with little influence of the vehicle or preservative agent used.
TL;DR: The results suggest that distinction between primary and secondary vitreous is difficult by classical histochemical techniques and electron microscopy, and that the vitreOUS glycosaminoglycans concentration seems to be high at 7th- and 8th-week embyonic stages and decreases at later fetal stages.
Abstract: The vascular and the avascular vitreous in 7th- and 8th-week human embryos and 9th-week fetuses were stained strongly by alcian blue, while marked decrease in staining by alcian blue was observed in 12th- and 13th-week human fetuses. The nature of alcian blue positive materials was identified as hyaluronic acid and chondroitin sulfate or dermatan sulfate by enzymatic digestion methods and the Scott-Dorling method. The results suggest that distinction between primary and secondary vitreous is difficult by classical histochemical techniques and electron microscopy, and that the vitreous glycosaminoglycans concentration seems to be high at 7th- and 8th-week embyonic stages and decreases at later fetal stages.
TL;DR: A parallel shift for the human pattern reversal ERG response to higher spatial frequencies is observed, in accordance with the difference in visual resolution in man and cat.
Abstract: In 42 enucleated and arterially perfused cat eyes, graded potentials were recorded from the retina (ERG) and from the optic nerve (ONR) in response to checkerboard stimuli, reversing at a low temporal frequency in a square wave mode. The ERG and ONR responses show an almost perfect duplication of the response to each reversal of the pattern and exhibit, in contrast to luminance responses, striking similarities in response characteristics such as amplitude, wave shape and time course. Furthermore, the amplitude versus check size plots coincide in both responses. In cat, pattern reversal responses can be recorded from 74 to 9 min of arc, correlating to the cat’s visual resolution. In man, almost identical responses can be recorded for the pattern ERG. However, in accordance with the difference in visual resolution in man and cat, a parallel shift for the human pattern reversal ERG response to higher spatial frequencies is observed.
TL;DR: Free amino acids were determined quantitatively in tear fluid and serum samples from the fasting blood of 21 healthy men and women and none of the 43 subjects showed any evidence of liver damage, kidney or metabolic disease.
Abstract: Free amino acids were determined quantitatively in tear fluid and serum samples from the fasting blood of 21 healthy men (aged 22-45 years) and 22 women (aged 21-56 years). Protein was removed from tears and serum by adding an equal volume of 5% sulfosalicyclic acid, and the amino acids were separated by ion exchange column chromatography. None of the 43 subjects showed any evidence of liver damage, kidney or metabolic disease. Men had significantly higher valine, isoleucine and histidine concentrations than women. The range of normal values was determined from these findings.
TL;DR: Ouabain-sensitive, K-dependent p-nitrophenylphosphatase (K- NPPase) activity of the Na-K- ATPase complex and the Ca-ATPase activity were studied ultracytochemically in the inner and outer segments of guinea pig photoreceptor cells by means of newly developed methods.
Abstract: Ouabain-sensitive, K-dependent p -nitrophenylphosphatase (K-NPPase) activity of the Na-K-ATPase complex and the Ca-ATPase activity were studied ultracytochemically in the inner and o
TL;DR: Only one subset of retinal ganglion cells, those excited by the short wave sensitive cones and inhibited by the other cones, can distinguish white/yellow contrast, implying that the paired opponent channels of Hering's colour vision theory do not exist in the retinogeniculate pathway.
Abstract: We have used pure hue contrast stimuli to examine the responses of single primate retinal ganglion cells. Only one subset of these cells, those excited by the short wave sensitive cones and inhibited
TL;DR: Differences between both species in processing chromatic stimuli can help to explain certain types of colour vision deficiencies in man.
Abstract: Cone mechanisms and colour opponency were investigated in 108 recordings from tonic ganglion cells of the rhesus monkey retina and 265 recordings from ganglion cells of the cat retina. Colour-opponent
TL;DR: In the light-sensitive epiphysis cerebri of adult frogs adapted in summer to an artificial long day, outer segments of cone-like pineal photoreceptor cells exhibit a cyclic and complete renewal.
Abstract: In the light-sensitive epiphysis cerebri of adult frogs (Rana esculenta) adapted in summer to an artificial long day (L:D = 17:7; L = 90 lx at 2,300°K; controlled temperature of 8°C) outer segments of cone-like pineal photoreceptor cells exhibit a cyclic and complete renewal. Shortly after ‘lights off’ inner segments protruding into the pineal lumen bear exclusively bulbous cilia of the sensory type. Considering these results, concepts dealing with different types of sensory pinealocytes have to be re-evaluated.
TL;DR: The spectral sensitivity of the European ground squirrel was investigated and it was concluded that the second spectral system is a blue cone system which in its rod-like properties is comparable to the blue cones found in cat, monkey and man.
Abstract: The spectral sensitivity of the European ground squirrel was investigated by electroretinography (ERG) and visual-evoked cortical potentials. Using chromatic adaptation, two spectral systems were found, one peaking between 520 and 530 nm, the other at 465 nm. The blue system was characterized by a slower course of the potential, a lower threshold and the lack of a d wave in the ERG. However, its threshold is higher than the rod threshold and it was shown to be more resistant to adapting light stimuli than rod systems are. It is concluded that the second spectral system is a blue cone system which in its rod-like properties is comparable to the blue cones found in cat, monkey and man.
TL;DR: Evidence is given for the decisive role of some prostaglandins and leukotrienes in inflammation in general, and in corneal inflammatory processes in special, in relation to polymorphonuclear leukocytes.
Abstract: Cyclooxygenase- and lipoxygenase-dependent compounds of arachidonic acid were studied in a corneal implantation technique concerning their chemotactic activity for polymorphonuclear leukocytes. Arachidonic acid, prostaglandins Aι, A2, B2, I2, thromboxane A2 and leukotriene D4 showed no activity, whereas leukotriene B4 was the most potent chemoattractant substance for polymorphonuclear leukocytes, followed by 5-HETE, prostaglandins E2 and E1· This gives evidence for the decisive role of some prostaglandins and leukotrienes in inflammation in general, and in corneal inflammatory processes in special
TL;DR: The electroretinographic rapid off-response, composed mainly of the late receptor potential of cones, is found to be abnormal in all protans and deutans so far tested and can be used as an objective measure in the diagnosis of congenital red-green colour defect.
Abstract: The electroretinographic rapid off-response, composed mainly of the late receptor potential of cones, is found to be abnormal in all protans and deutans so far tested. The rapid off-response can thus be used as an objective measure in the diagnosis of congenital red-green colour defect.
TL;DR: The supposed close negative correlation between length of the globe and ocular coat dimensions was confirmed and should provide additional help, when interpreting the reflections of the ocular wall under normal and pathological conditions.
Abstract: In various states of refraction axial eye length and thickness of the posterior ocular coats were measured echographically. As proved in previously performed experimental studies, retina, choroid and sclera were resolved in a considerable percentage of cases by combining the A- and B-mode techniques of modern ultrasonic equipment. The supposed close negative correlation between length of the globe and ocular coat dimensions was confirmed by statistical analysis of our data. This result should provide additional help, when interpreting the reflections of the ocular wall under normal and pathological conditions.
TL;DR: Complete closure of the epithelium over the lesion after 1 day was observed much more frequently in the group of patients treated with Solcoseryl Eye-Gel than in the reference group (63 vs. 53%).
Abstract: Solcoseryl, a protein-free haemodialysate, promotes tissue regeneration and improves utilization of oxygen in the cell. In a randomized, double-blind, clinical study, Solcoseryl Eye-Gel was compared with Cysteine Eye-Gel in the treatment of foreign-body injuries of the cornea in a total of 99 eyes. In order to facilitate objective evaluation of the effects of the treatment, the area of the lesion before the start of treatment and on the following day was determined by means of slit-lamp photographs. Healing of the lesion and relative reduction of the area of the wound were observed much more frequently in the group treated with Solcoseryl Eye-Gel than in the reference group. Maculae corneae after the end of the treatment were significantly less frequent under Solcoseryl Eye-Gel than under Cysteine Eye-Gel. Teh tolerability of the test preparation was good; an itching sensation was reported in only 2 cases. Under Cysteine Eye-Gel, on the other hand, a burning sensation was reported by a number of patients and very fine deposits in the epithelium were also observed in a few cases. Thus complete closure of the epithelium over the lesion after 1 day was observed much more frequently in the group of patients treated with Solcoseryl Eye-Gel than in the reference group (63 vs. 53%).