scholarly journals Quantum Relations of the Rat Electroretinogram

1963 ◽  
Vol 46 (6) ◽  
pp. 1267-1286 ◽  
Author(s):  
Richard A. Cone
Keyword(s):  
Wave Amplitude ◽  
Inner Nuclear Layer ◽  
Intensity Scale ◽  
Rat Retina ◽  
The Individual ◽  
Wave Latency ◽  
Near Threshold

The rat retina is uniform and contains almost exclusively rods. Therefore the rat eye, when uniformly illuminated, produces a gross electroretinogram (ERG) which is simply related to the activity of the individual retinal sources of the ERG. Characteristics of ERG's are shown on an intensity scale of the average number of quanta absorbed per rod per stimulus flash obtained by direct accurate measurement of all quantities involved. An independent check on the accuracy of these measurements is applied to pigment-bleaching data reported by Dowling (1963). When ERG characteristics are placed on this scale it is found that: (a) The b-wave can usually be observed when fewer than one out of two hundred rods absorbs a quantum, the threshold being determined by the noise of the preparation. (b) Near threshold the b-wave amplitude is proportional to intensity. (c) The a-wave appears when there are more than two to four absorptions per rod per flash. (d) The b-wave latency decreases with intensity, and the amplitude becomes proportional to the logarithm of intensity when fewer than one out of ten rods absorbs a quantum. This implies that the b-wave sources must combine excitation from more than one rod (probably more than seven). Therefore the b-wave cannot arise from independent rods or rod-bipolar synapses, but probably reflects activity of entire inner nuclear layer cells.

scholarly journals Electrical activity in rat retina in a streptozotocin-induced diabetes model

2018 ◽  
Vol 21 (5) ◽  
pp. 356-363
Author(s):  
Ekaterina M. Klochihina ◽  
Aleksey K. Erdyakov ◽  
Maria P. Morozova ◽  
Svetlana A. Gavrilova ◽  
Elena S. Akhapkina ◽  
...  
Keyword(s):  
Diabetic Retinopathy ◽  
Wave Amplitude ◽  
Developed Countries ◽  
Laboratory Animals ◽  
Control Group ◽  
Oscillatory Potential ◽  
Ischaemic Injury ◽  
Rhythmic Stimulation ◽  
Potential Test ◽  
Wave Latency

Objectives: Diabetic retinopathy remains the major cause of blindness among the working-age population of developed countries. Considering this, experimental models of diabetes involving laboratory animals are important for assessing clinically significant methods to determine early pathologic alterations of the retina. The early detection of diabetic retinopathy in combination with a search for new pathogenetic targets will enable focusing on new strategies to limit the development of critical changes in the retina and to prolong retinal functioning during the development of diabetes mellitus. Aim: This study aimed to define parameters of electroretinography test that identifies changes due to retinal impairment in diabetes. Methods: Experimental diabetes was induced in Wistar rats by intraperitoneally injecting streptozocin (65 mg/kg; group DM). The control group (CB) received intraperitoneal injections of the vehicle, i.e. citric buffer. On each consecutive day of the experiment, all rats received insulin detemir (2 u/kg). Ophthalmoscopy and electroretinography were conducted before initiating the experiment and after 50, 58 and 66 days of injectin sptreptozocin. Results: Amid 2u\kg insulin injection the glucose level in venous blood in DM group amounted to 30-40 mM. The ophthalmoscopy showed that the optic nerve disk paled by the 50th day, with its line erasing. During electroretinography, wave amplitude in oscillatory potential test tended to decrease. -wave latency of photopic system increased with -wave latency of photopic system and - and -waves latency of scotopic system not altering. In addition, the amplitude of rhythmic stimulation of 8 and 12 Hz decreased. Conclusion: The most apparent parameters of electroretinography for modelling streptozocin-induced diabetes are wave amplitude during the oscillatory potential test, photopic B-wave latency and the amplitude of rhythmic stimulation. These results suggest that in diabetes, ischaemic injury is an important cause of early dysfunction of inner retinal layers.

Tsunami intensity scale based on wave amplitude and current applied to the French Riviera: the case study of local seismicity

2020 ◽  
Vol 102 (1) ◽  
pp. 219-248
Author(s):  
Laurie Boschetti ◽  
Mansour Ioualalen ◽  
Fatemeh Nemati ◽  
Stephan Grilli ◽  
Jean-Xavier Dessa ◽  
...  
Keyword(s):  
Wave Amplitude ◽  
Intensity Scale ◽  
Local Seismicity ◽  
Tsunami Intensity ◽  
French Riviera

Photoelectron Diffraction Imaging of Microcrystallites on the Surface of a Ni Polycrystal

1998 ◽  
Vol 05 (02) ◽  
pp. 501-513 ◽  
Author(s):  
M. Zharnikov ◽  
M. Neuber ◽  
M. Grunze
Keyword(s):  
Electron Microscopy ◽  
Crystallographic Orientation ◽  
Optical Method ◽  
Optical Microscope ◽  
Forward Scattering ◽  
Intensity Scale ◽  
Photoelectron Diffraction ◽  
Diffraction Imaging ◽  
Variable Direction ◽  
The Individual

The applicability of the forward scattering of photoelectrons in electron microscopy is demonstrated for the characterization and investigation of the polycrystalline substrates. The well-resolved images of individual microcrystallites on the surface of Ni polycrystal have been obtained by using the Ni 2p3/2 photoelectrons (E kin = 635 eV ) collected at a widely variable direction of emission. By using the forward scattering approach, not only crystallites resolved by an optical microscope but also the microcrystallites, which were not distinguished by the optical method, have been easily identified through the photoelectron diffraction contrast. This contrast amounted to almost 50% of the whole intensity scale and could be observed directly during the acquisition of the images. Crystallographic information on the orientation of the microcrystallites constituting the polycrystal was obtained: some crystallites with the low index surfaces were identified, some microcrystallites with the same orientation were recognized, and the symmetry of the surfaces of the individual crystallites was partly controlled. An approximate identification of the crystallographic orientation of several individual microcrystallites in the investigated Ni polycrystal has been achieved.

scholarly journals Electrophysiological parameters in patients with the «dry» form of age-related macular degeneration treated with polarized polychromatic non-coherent light and dynamic electromyostimulation

2012 ◽  
Vol 93 (6) ◽  
pp. 961-965
Author(s):  
F R Saifullina ◽  
R Z Sharafieva ◽  
V I Pogorel’tsev ◽  
E A Abdulaeva
Keyword(s):  
Macular Degeneration ◽  
Wave Amplitude ◽  
Light Stimulus ◽  
Combined Treatment ◽  
Red Light ◽  
Age Related Macular Degeneration ◽  
Control Group ◽  
Coherent Light ◽  
Age Related ◽  
Wave Latency

Aim. To study the electrophysiological parameters in patients with the «dry» form of age-related macular degeneration before and after combined treatment with polarized polychromatic non-coherent light and dynamic electromyostimulation. Methods. Two groups of patients with the «dry» form of age-related macular degeneration were examined. Patients in the main group (40 patients, 80 eyes) were treated with a combination of polarized polychromatic non-coherent light and dynamic electromyostimulation, patients in the control group (39 patients, 78 eyes) were treated conventionally. Mean age of the patients was 71.3±1.1 years. All patients underwent standard ophthalmic examination. To assess the functional status of the macula, electroretinography was performed using the «Neuro-MVP» device (Ivanovo, Russia). A-wave amplitude and latency on the red light stimulus were examined. Results. A-wave amplitude on macular electroretinogram was 11.9% lower and A-wave latency was 20.8% higher in patients with age-related macular degeneration compared to healthy subjects. A statistically significant improvement of the A-wave amplitude and latency was observed on macular electroretinogram after the combined treatment. A-wave amplitude increased from 13.22±1.36 to 17.17±1.59 µV (p 0.01) after 2 months and up to 17.80±1.60 µV (p 0.05) after 6 months of treatment. A-wave latency decreased from 19.32±0.41 to 18.51±0.36 ms (p 0.01) after 2 months and down to 18.31±0.45 ms (p 0.05) after 6 months of treatment. There was a relevant increase in A-wave amplitude from 13.15±1.09 to 16.3±1.09 µV (p 0.01) and decrease in A-wave latency from 19.23±0.30 to 18.64±0.30 ms (p 0.05) in patients of the control group 2 months after the end of treatment. Conclusion. There were relevant increase in A-wave amplitude and decrease in A-wave latency observed on macular electroretinography after treatment. The proposed treatment method does not cause any complications and can be used as a treatment option in patients with allergic reactions to standard drugs.

Tracer coupling of neurons in the rat retina inner nuclear layer labeled by Fluorogold

2005 ◽  
Vol 1063 (2) ◽  
pp. 114-120 ◽  
Author(s):  
Raja' M. Abdel-Majid ◽  
Michele L. Archibald ◽  
François Tremblay ◽  
William H. Baldridge
Keyword(s):  
Inner Nuclear Layer ◽  
Rat Retina

Somatostatin and prosomatostatin in the retina of the rat: An immunohistochemical, in-situ hybridization, and chromatographic study

1990 ◽  
Vol 5 (5) ◽  
pp. 441-452 ◽  
Author(s):  
Jens Nicolai Brink Larsen ◽  
Maurizio Bersani ◽  
James Olcese ◽  
Jens Juul Holst ◽  
Morten Møller
Keyword(s):  
Ganglion Cell ◽  
Ganglion Cell Layer ◽  
Cell Layer ◽  
Gel Filtration ◽  
Plexiform Layer ◽  
Inner Nuclear Layer ◽  
Inner Plexiform Layer ◽  
Rat Retina ◽  
Cell Layers

AbstractSpecific antisera, raised in rabbits, against somatostatin 1-14, somatostatin 1-28, the fragment 1-12 of somatostatin 1-28, and prosomatostatin 20-36 were used for immunohistochemistry and gel filtration of the rat retina.With all antisera, immunoreactive perikarya could be located in the inner nuclear and ganglion cell layers. In the inner nuclear layer, amacrine cells with processes extending predominantly into the first sublayer of the inner plexiform layer were observed. Some processes extended also to the ganglion cell layer. In addition, somatostatin-immunoreactive interplexiform cells were present in the inner nuclear layer.In the ganglion cell layer, perikarya were found located in the midperiphery and in the far periphery of the retina. The neurons located in the midperiphery of the retina possessed a round perikaryon from which processes could be followed going into the inner plexiform layer, where they dichotomized in the third and first sublayers. The perikarya in the far periphery of the retina near the ora serrata exhibited an ovoid-shaped cell body from which processes extended horizontally in a bipolar manner in the layer itself.By use of an [35S]-labeled antisense oligonucleotide probe, in situ hybridization of the rat retina showed the presence of perikarya in the inner nuclear layer and ganglion cell layer containing mRNA encoding for prosomatostatin.Gel filtration of the retinal extracts followed by radioimmunoassay showed the presence of somatostatin 1-14, the fragment 1-12 of somatostatin 1-28, and prosomatostatin 1-64. However, somatostatin 1-28 was not detected.The results obtained in this study verify the presence of somatostatin 1-14 in the rat retina located in perikarya and processes in the inner nuclear and ganglion cell layers. The positive in-situ hybridization signals show that the intraneuronal somatostatin immunoreactivity is due to synthesis of the peptide and not uptake in the neurons. The presence of the somatostatin propeptide and fragments of this propeptide, in both intraretinal perikarya and fibers, indicate a posttranslational modification of this neuropeptide in the perikarya and the processes as well.

The Influence of R-Wave Amplitude on the Degree of ST-Segment Depression in Exercise Electrocardiography in the Individual Patient

Angiology ◽  
1987 ◽  
Vol 38 (1) ◽  
pp. 22-27 ◽  
Author(s):  
Dennis V. Cokkinos ◽  
Apostolos Papantonakos ◽  
Costas Perrakis ◽  
Spyros Argyrakis ◽  
George Kouvaras ◽  
...  
Keyword(s):  
Wave Amplitude ◽  
Exercise Electrocardiography ◽  
St Segment ◽  
The Individual ◽  
R Wave Amplitude
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