• 제목/요약/키워드: retinal

검색결과 468건 처리시간 0.032초

Photoreception for Photoperiodism and Circadian Rhythms in the Blow Fly

  • Shiga, Sakiko;Numata, Hideharu
    • Journal of Photoscience
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    • 제9권2호
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    • pp.13-16
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    • 2002
  • A comparison of the functional components underlying photoperiodism and circadian rhythmicity in the same species is an interesting issue in the context of unravelling clock mechanisms. In the present study, covering or surgical removal of the compound eyes was performed to localize photoreceptors for photoperiodism to control reproductive diapause and for entrainment of circadian locomotor rhythms in the blow fly Protophormia terraenovae. Intact flies showed a long-day photoperiodic response. When the compound eyes were covered by silver paint, diapause incidence increased under diapause-averting conditions of a long-day photoperiod and constant light, as if flies were kept under constant darkness. Covering of a medial region of the head capsule or solvent painting of the compound eyes gave no significant effects. When the compound eyes were removed, flies did not distinguish the photoperiod, whereas removal of antennal lobes or ocelli did not affect the photoperiodism. Intact flies showed a freerunning rhythm under constant darkness. The rhythm entrained to light-dark (LD) cycles with light of high and low intensity. When the compound eyes and ocelli were surgically removed, the rhythm entrained to LD cycles with light of high intensity but freeran under LD cycles with light of low intensity. The results suggest the retinal pathways are involved in photoperiodism and that flies use both retinal and extraretinal pathways for rhythm entrainment. Under dim light-LD cycles, the retinal pathways mainly mediate rhythm entrainment. Retinal photoreceptors seem to be used both for photoperiodism and entrainment of the rhythm.

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Electrophysiological Analysis of GABA and Glycine Action on Neurons of the Catfish Retina

  • Bai, Sun-Ho;Jung, Chang-Sub;Lee, Sung-Jong
    • The Korean Journal of Physiology
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    • 제27권2호
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    • pp.163-174
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    • 1993
  • Vertebrate retinal neurons, like brain tracts farm complex synaptic relations in the enter and inner plexiform layers which ape equivalent to the central nervous system nuclei. The effects of $\gamma-aminobutyric$ acid(GABA) and glycine on retinal neurons were explored to discern the mechanisms of action of neurotransmitters. Experiments were performed in the superfused retina-eyecup preparation of the channel catfish, Ictalurus punctatus, using intracellular electrophysiological techniques. The roles of GABA and glycine as inhibitory neurotransmitters are well established in the vertebrate retina. But, we found that the depolarizing action of GABA and glycine on third-order neurons in the catfish retina. GABA and glycine appeared to act on retinal ueurons based on the observations that (1) effects on photoreceptors were not observed, (2) horizontal cells were either hyperpolarized $({\sim}33%)$ or depolarized $({\sim}67%)$, (3) bipolar cells were all hyperpolarized (4) amacrine and ganglion cells were either hyperpolarized $({\sim}37%)$ or depolarized $({\sim}63%)$, (5) GABA and glycine may be working to suppress presynaptic inhibition. The results suggest that depolarization of third-order neurons by GABA and glycine is due to at least two mechanisms; a direct postsynaptic effect and an indirect effect. Therefore, in the catfish retina, a mechanism of presynaptic inhibition or disinhibition including the direct postsynaptic effect may exist in the third-order neurons.

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One-step isolation of sappanol and brazilin from Caesalpinia sappan and their effects on oxidative stress-induced retinal death

  • Uddin, Golam Mezbah;Kim, Chul Young;Chung, Donghwa;Kim, Kyung-A;Jung, Sang Hoon
    • BMB Reports
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    • 제48권5호
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    • pp.289-294
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    • 2015
  • Caesalpinia sappan is a well-distributed plant that is cultivated in Southeast Asia, Africa, and the Americas. C. sappan has been used in Asian folk medicine and its extract has been shown to have pharmacological effects. Two homoisoflavonoids, sappanol and brazilin, were isolated from C. sappan by using centrifugal partition chromatography (CPC), and tested for protective effects against retinal cell death. The isolated homoisoflavonoids produced approximately 20-fold inhibition of N-retinylidene-N-retinyl-ethanolamine (A2E) photooxidation in a dose-dependent manner. Of the 2 compounds, brazilin showed better inhibition (197.93 ± 1.59 μM of IC50). Cell viability tests and PI/Hoechst 33342 double staining method indicated that compared to the negative control, sappanol significantly attenuated H2O2-induced retinal death. The compounds significantly blunted the up-regulation of intracellular reactive oxygen species (ROS), and sappanol inhibited lipid peroxidation in a concentration-dependent manner. Thus, both compounds represent potential antioxidant treatments for retinal diseases. [BMB Reports 2015; 48(5): 289-294]

Infant Retinal Images Optic Disk Detection Using Active Contours

  • Charmjuree, Thammanoon;Uyyanonvara, Bunyarit;Makhanov, Stanislav S.
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2004년도 ICCAS
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    • pp.312-316
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    • 2004
  • The paper presents a technique to identify the boundary of the optic disc in infant retinal digital images using an approach based on active contours (snakes). The technique can be used to be develop a automate system in order to help the ophthalmologist's diagnosis the retinopathy of prematurity (ROP) disease which may occurred on preterm infant,. The optic disc detection is one of the fundamental step which could help to create an automate diagnose system for the doctors we use a new kind of active contour (snake) method has been developed by Chenyang et. al. [1], based on a new type of external force field, called gradient vector flow, or GVF. GVF is computed as a diffusion of the gradient vectors of a gray-level or binary edge map derived from the image. The testing results on a set of infant retinal ROP images verify the effectiveness of the proposed methods. We show that GVF has a large capture range and it's able to move snakes into boundary concavities of optic disc and finally the optic disk boundary was determined.

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망막정맥폐쇄증의 한약치료 임상연구에 대한 문헌 고찰 - 중국논문을 중심으로 (Literature Review of Clinical Research Herbal Treatment on Retinal Vein Occlusion - Focusing on Traditional Chinese Medicine's Journals -)

  • 강태규;선승호;이선구
    • 동의생리병리학회지
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    • 제30권4호
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    • pp.209-218
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    • 2016
  • The objective of this study was to investigate the diagnosis and treatment of Retinal vein occlusion such as syndrome differentiation and herbal medicine by reviewing Chinese traditional medicine`s journals. The journal search was carried out using China National Knowledge Infrastructure and Pubmed from January 2000 to December 2014. Searching key words were the various combination of "Retinal vein occlusion", "traditional chinese medicine", "syndrome differentiation". The final selection of 11 studies were selected and summarized by researchers. The effective rate was significantly higher than control but, methodological quality of the trials was generally low questioning their liability. The syndrome differentiation was classified as hyperactivity of liver yang and blood stasis. The most frequently prescribed herbal medication was Hyulbuchookeotang, Boyanghwanotang and Cheomagudeungum. This finding could be widely utilized in future clinical practice and form the basis for the development of clinical practice guidelines in advance.

양측성 망막분지정맥폐쇄의 임상적 고찰 (Clinical Observation of the Bilateral Branch Vein Occlusion)

  • 박영훈;한덕기;이상범
    • Journal of Yeungnam Medical Science
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    • 제10권1호
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    • pp.77-81
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    • 1993
  • 1984년 12월부터 1992년 1월까지 망막분지정맥폐쇄환자 4명 8안을 대상으로 임상적 고찰을 하였다. 발병연령은 36세에서 65세까지였고, 반대쪽 눈에 발병하기까지는 3년 이하가 3명이였으며 여자가 3명이였다. 동반질환은 고혈압이 3명으로 가장 많았다. 합병증으로 망막신생혈관이 6안(75%)에서 발생하였으며 초자체 출혈을 갖는 5안중 3안에서 초자체 절제술을 시행하였다. 고혈압이 있는 60대 까지의 여성에서 발생한 망막분지정맥폐쇄는 반대쪽 눈에 대한 주의 깊은 추적검사가 필요할 것으로 생각된다.

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망막분지정맥폐쇄로 유발된 황반부종 치험 1례 (A Case of Macular Edema Resulted from Branch Retinal Vein Occlusion)

  • 김지현;허은정;권강
    • 한방안이비인후피부과학회지
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    • 제23권2호
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    • pp.186-195
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    • 2010
  • Objective : This study was performed to prove the effect of the oriental medical treatments like acupuncture, moxibustion, herbal medicine on macular edema resulted from branch retinal vein occlusion which could lead to terrible result like permanent visual loss at worst. Methods : The patient was treated 62 times, from July 15th, 2009 through May 12th, 2010. We used fundus photography and Dr. Hann's standard test chart for 5m to examinate the patient's eyesight. We used acupuncture, electropuncture, moxibustion and herbal medicine to treat the patient. We considered visual field, scotoma, metamorphopsia and vitreous floater to measure the effect of treatment. Results : After about 10 months of treatment, the eyesight of Rt eye was improved from 0.8 to 0.9, Lt. eye from zero to 0.3. The visual field turbidity were absolutely cleared. The scotomas in Lt. eye were reduced from 5 to 2. The metamorphopsia were improved. The vitreous floaters in Rt. eye were decreased from 5~6 to 1~2. Conclusion : These results show that the oriental medical treatment can be conservative measure to the macular edema resulted from branch retinal vein occlusion.

A Case of Valsalva Retinopathy Associated with Straining at Stool

  • Lee, Tae-Yoon;Chang, Woo-Hyok
    • Journal of Yeungnam Medical Science
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    • 제23권2호
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    • pp.227-231
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    • 2006
  • 기도가 닫힌 상태에서 강하게 숨을 뿜어내는 발살바법은 망막의 정맥압을 상승시키고 이에 따라 망막 출혈을 유발시킬 수 있다. 힘든 배변을 경험한 55세 남자가 우안의 중심시력 감소로 인해 본원을 방문하였다. 전신적인 질환으로 고혈압, 만성 변비를 앓고 있었고 동공을 산대하여 정밀 안저검사를 한 결과 유두 한 개 정도 크기의 망막전 출혈과 황반와주위로 작은 크기의 망막내 출혈이 관찰되었다. 특별한 치료없이 망막 출혈은 자연 흡수되어 시력은 정상으로 회복되었다. 배변으로 인해 급작스런 시력감퇴를 나타낸 발살바 망막증을 경험하였기에 보고하는 바이다.

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網膜中心動脈閉鎖 患者 1例에 對한 臨床的 考察 (Clinical study on 1 Case of Patient with Obstruction of the retinal artery)

  • 이준성;류현신;서형식;노석선
    • 한방안이비인후피부과학회지
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    • 제14권2호
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    • pp.224-230
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    • 2001
  • In the Clinical study on 1 Case of Patient with Obstruction of the retinal artery, the results were as follows. 1. Obstruction of the retinal artery is acute disease that vision isdiminished fastly and become a blindness. 2. It belong to the cathegory of Pock Maeng(暴盲) in Oriental Medicine. 3. The causes of Obstruction of the retinal artery were the yin-deficiency of liver and kidney, the stagnation of vital energy and blood stasis, the abundance of phlegm-heat, the yang-deficiency of spleen and kidney, the yin-deficiency of spleen and kidney, the nonfastness of primordial energy etc. 4. We could get the effective result by providing the patient with Jinkansikpung-tang-gami(鎭肝熄風湯加味) in the acute period 5. In Acupuncture treament and other treament, Electro-acupuncture theraphy ana Lodestone theraphy were useo for neurologic stimulation, Body acupuncture and Auricula-acupuncture were used for promoting the circulation of vital energy and blood.

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고혈당으로 유도된 제브라피쉬 당뇨망막병증 모델에서 약용식물의 효능 평가 (In vivo Screening of Herbal Extracts on High Glucose-induced Changes in Hyaloid-Retinal Vessels of Zebrafish)

  • 이유리;정승현;이익수;김주환;김영숙;김진숙
    • 생약학회지
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    • 제50권1호
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    • pp.25-31
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    • 2019
  • The zebrafish (Danio rerio) is an established model organism for several pathophysiological conditions which are related to human diseases. In this study, we tested the preventive effect of eight herbal extracts, which show the inhibitory effect of advanced glycation end products (AGEs) or aldose reductase (AR) in our previous study, on high glucose (HG)-induced retinal vessel dilation in larval zebrafish and analyzed the change of hyaloid vasculature. HG-induced zebrafish hyaloid vasculatures were significantly increased in the thickness compared to untreated zebrafish (P<0.001, n=6~10). Eight herbal extracts were found to have significant retinal vessel dilation on the inhibitory activity. Particularly, Brandisia hancei (twigs and fruits), Castanopsis orthacantha (leaves and twigs), Litsea japonica (leaves and twigs), Spenceria ramalana (whole plant), and Synedrella nodiflora (leaves and stems) showed potent inhibitory activity against retinal vessel dilation in HG-induced larval zebrafish.