Cone cGMP-gated channel mutations and clinical findings in patients with achromatopsia, macular degeneration, and other hereditary cone diseases

Unrelated patients with achromatopsia, macular degeneration with onset under age 50 years, cone degeneration or dysfunction, cone-rod degeneration, or macular malfunction were screened for mutations in the three genes known to be associated with achromatopsia: the GNAT2 gene encoding the alpha subunit of cone transducin and the CNGA3 and CNGB3 genes encoding the alpha and beta subunits of the cone cGMP-gated cation channel. We found no examples of patients with GNAT2 mutations. Out of 36 achromats, 12 (33%) had mutations in CNGA3 (13 different mutations including five novel mutations) and 12 (33%) had mutations in CNGB3 (six different mutations including four novel mutations). All achromats with CNG mutations had residual, presumably cone function as determined by computer-averaged 30-Hz electroretinograms (ERGs). There was considerable variability in acuity and color vision, with most patients having acuities of 20/200-20/400 and complete absence of color perception, and others having acuities of 20/25-20/40 and some color vision. Two pseudodominant achromatopsia cases were uncovered, both with CNGA3 mutations, including one family in which some compound heterozygotes with achromatopsia mutations were clinically unaffected. We found two novel CNGB3 changes in three patients with juvenile macular degeneration, a phenotype not previously associated with mutations in the cone channel subunits. These patients had subnormal acuity (20/30-20/60), normal to subnormal color vision, and normal to subnormal full-field cone ERG amplitudes. Our results indicate that some patients with channel protein mutations retain residual foveal cone function. Based on our findings, CNGB3 should be considered as a candidate gene to be evaluated in patients with forms of cone dysfunction, including macular degeneration.     

Effects of pinealectomy and exogenous melatonin on rat hearts

The effects of pinealectomy and administration of melatonin, the major secretory product of the pineal gland, which is a direct free radical scavenger and an indirect antioxidant, were studied in rat hearts on the basis of cardiac morphology and biochemical findings. Three groups of Wistar rats were used: one group was the sham-operated control, one group consisted of pinealectomized rats and one group consisted of pinealectomized rats that were treated with melatonin. Serum cholesterol, tissue levels of malondialdehyde (MDA) and reduced glutathione (GSH), and heart weight were determined. Histochemical staining with the Van Gieson, PAS/Alcian blue at pH 2.5 and Masson's trichrome methods were performed in addition to hematoxylin-eosin staining. Levels of serum cholesterol and tissue MDA, and heart weight were increased in pinealectomized rats whereas GSH levels did not change. Melatonin administration reversed these effects. Microscopically, myocardial fibrosis and myxomatous degeneration of cardiac valves were detected in all pinealectomized rats. It can be concluded that pinealectomy of rats causes morphological changes in rat hearts, and short-term application of melatonin does not reverse these changes.     

阿魏酸钠治疗视网膜静脉栓塞疗效观察

目的探讨阿魏酸钠注射液治疗视网膜静脉栓塞的临床效果。方法100例（100只眼）视网膜静脉栓塞患者，随机分成治疗组和对照组各50例。对照组给予常规治疗，治疗组给予阿魏酸钠注射液300mg／d静脉滴注，14d为一疗程。测定治疗前后视力、视网膜中央静脉血流速度、视网膜中央动脉平均收缩期峰值血流速度。结果应用阿魏酸钠治疗后，视力明显改善，视网膜中央静脉血流速度和收缩期峰值血流速度显著提高，与对照组治疗后相比均有显著性差异，疗效优于对照组。结论阿魏酸钠治疗视网膜静脉栓塞疗效显著。     

Genetic testing for inherited eye conditions in over 6,000 individuals through the eyeGENE network

Genetic testing in a multisite clinical trial network for inherited eye conditions is described in this retrospective review of data collected through eyeGENE®, the National Ophthalmic Disease Genotyping and Phenotyping Network. Participants in eyeGENE were enrolled through a network of clinical providers throughout the United States and Canada. Blood samples and clinical data were collected to establish a phenotype:genotype database, biorepository, and patient registry. Data and samples are available for research use, and participants are provided results of clinical genetic testing. eyeGENE utilized a unique, distributed clinical trial design to enroll 6,403 participants from 5,385 families diagnosed with over 30 different inherited eye conditions. The most common diagnoses given for participants were retinitis pigmentosa (RP), Stargardt disease, and choroideremia. Pathogenic variants were most frequently reported in ABCA4 (37%), USH2A (7%), RPGR (6%), CHM (5%), and PRPH2 (3%). Among the 5,552 participants with genetic testing, at least one pathogenic or likely pathogenic variant was observed in 3,448 participants (62.1%), and variants of uncertain significance in 1,712 participants (30.8%). Ten genes represent 68% of all pathogenic and likely pathogenic variants in eyeGENE. Cross‐referencing current gene therapy clinical trials, over a thousand participants may be eligible, based on pathogenic variants in genes targeted by those therapies. This article is the first summary of genetic testing from thousands of participants tested through eyeGENE, including reports from 5,552 individuals. eyeGENE provides a launching point for inherited eye research, connects researchers with potential future study participants, and provides a valuable resource to the vision community.     

Genetic susceptibility to age related macular degeneration

Age related macular degeneration (AMD) is the leading cause of visual impairment in the elderly and a major cause of blindness in the developed world. The disease can take two forms, geographic atrophy and choroidal neovascularisation. The pathogenesis of AMD is poorly understood. There are undoubtedly environmental and other risk factors involved and the adverse effect of smoking is well established. Several studies have shown that genetic factors are important but leave uncertainty about the magnitude and nature of the genetic component and whether it varies with the type of AMD. Several hereditary retinal dystrophies show similarities to AMD and these genes are potential candidate susceptibility genes. Particular interest has focused on the ABCR gene which is responsible for autosomal recessive Stargardt macular dystrophy. It has been claimed that heterozygotes for ABCR mutations are predisposed to AMD but the data are conflicting. Studies of the genes responsible for autosomal dominant Sorsby fundus dystrophy, Doyne honeycomb retinal dystrophy, and Best disease have given negative results. In one large AMD family, linkage has been reported to markers in 1q25-q31. Recent data suggest that the ApoE epsilon4 allele may be associated with reduced risk of AMD. A better understanding of the genetic factors in AMD would contribute to understanding the pathogenesis. If those at risk could be identified it may be possible to modify lifestyle or develop novel therapies in the presymptomatic stage to prevent disease or decrease its severity.     

降钙素治疗延缓卵巢切除大鼠腰椎间盘退变

目的:观察降钙素对卵巢切除大鼠腰椎骨量及椎间盘退变的影响。方法:SD大鼠分为基线对照组、假手术组、卵巢切除组及降钙素治疗组,进行腰椎节段骨密度和骨形态计量学分析,观察椎间盘的组织形态学改变。结果:卵巢切除组骨量较对照组和降钙素治疗组显著下降,骨转化指标明显提高。降钙素治疗组的腰椎间盘组织学评分较卵巢切除组显著下降。结论:卵巢切除大鼠椎间盘退变可能是骨量减少引起的脊柱力学改变所致,降钙素治疗可以预防骨量丢失并延缓其腰椎间盘退变。     

Enhanced sprouting of retinotectal fibers after early superior colliculus lesions in hamsters treated with gangliosides

Summary The effects of exogenous gangliosides on sprouting of optic tract axons was studied in hamsters which, after a right tectal lesion on the day after birth (P1), had an abnormal retinotectal projection from the left eye to the left superior colliculus (SC). Sprouting of these axons was induced by removing the competing input by right eye removal on postnatal day 9 (P9). Intraperitoneal G_M1, given daily and started on P9, significantly stimulated the sprouting response. This was demonstrated by Fink-Heimer silver staining of anterograde axonal degeneration three days after the left eye was removed on P36. Terminal fields in the left SC were, in average, twice as large compared to controls. An estimate of the total number of terminals (silver stained particles) revealed a value of 7.9×10⁶ for G_M1 and 3.2×10⁶ for control hamsters, respectively. Diencephalic structures which also receive collateral input from the sprouting optic tract did not show any alterations in the size of the terminal field due to G_M1-treatment, suggesting that, in vivo, gangliosides fail to initiate sprouting in areas that have not previously been denervated. Unexpectedly, G_M1-treated hamsters also had significantly smaller right SC damage and less left damage near the midline. Subsequent reanalysis of the data based on a lesion-matching procedure indicates that effects on reducing atrophy were independent of the G_M1-enhanced sprouting of retinofugal axons. These findings provide the first direct evidence that exogenous G_M1 stimulates lesion-induced axon sprouting in the mammalian brain.     

NGF prevents further atrophy of cholinergic cells of the nucleus basalis due to cortical infarction in adult post-hypothyroid rats but does not restore cell size compared to euthroid rats

We have tested the hypotheses that nerve growth factor treatment in adult post-hypothyroid rats can: (1) restore cross-sectional area of cholinergic cells of the nucleus basalis and (2) prevent further atrophy of these neurons following cortical infaction. In addition, we assessed the expression of p75^NGFR and p140^trkA mRNAs in the nucleus basalis cells of post-hypothyroid rats. Rats were rendered hypothyroid by the addition of propylthiouracil to their diet beginning on embryonic day 19 until the age of 1 month. At this time both the pups and their dams continued to receive 0.05% propylthiouracil in their diet and the pups were thyroidectomized. At 60 days, propylthiouracil treatment was interrupted and thyroxine levels were restored to normal by daily subcutaneous administration of physiological levels of thyroxine. Morphometric analysis identified atrophied nucleus basalis magnocellularis cholinergic cells at two ages, days 75 and 105, identified by in situ hybridization for p75^NGFR and p140^trkA mRNAs in methylene blue stained cells (day 75) and choline acetyltransferase immunostaining (day 105). The mean number of silver grains (pixels) per μm² (mean±S.E.M.) of cell body cross-sectional area for p75^NGFR mRNA in the nucleus basalis magnocellularis of euthyroid rats was 3.43±0.89, which was not statistically different from post-hypothyroid animals (4.02±1.07). A similar finding was noted for p140^trkA mRNA: mean number of grains in the euthyroid group was 5.54±0.96 and was not statistically different from the post-hypothyroid group (6.32±1.45). Nerve growth factor treatment in adulthood (between days 75 and 82) did not restore cross-sectional area from early thyroid deprivation. However, it prevented further atrophy of nucleus basalis magnocellularis neurons following cortical devascularization inflicted in adulthood (day 75).     

Fertilization and early embryology: Effects of embryo density and co-culture of unfertilized oocytes on embryonic development of in-vitro fertilized mouse embryos

We have evaluated the effects of embryo density and the co-cultureof unfertilized (degenerating) oocytes on the development ofin-vitro fertilized (IVF) mouse embryos. In experiment 1, groupsof one, five, 10 or 20 zygotes were cultured in 20 µldrops of modified human tubal fluid (HTF) medium for 168 h at38.7°C in 5% CO₂ and 95% air. As the embryo density increased,significantly (P < 0.05) higher rates of embryos reachedhatched blastocyst stage. In addition, the time required forhatching after IVF was significantly (P < 0.05) shortenedby the increase in embryo density. In experiment 2, 10 IVF zygoteswere cultured with or without 10 unfertilized (degenerating)oocytes in 20 µl drops of HTF medium. The rates of IVFembryos that developed to morula, blastocyst, expanded blastocystand hatched blastocyst stages were decreased significantly (P< 0.01) by culturing embryos with unfertilized oocytes comparedwith culturing embryos alone. In experiment 3, groups of oneor 10 IVF zygotes or 10 IVF zygotes plus 10 unfertilized oocyteswere cultured in 20 µl drops of HTF medium and the numberof cells per blastocyst was examined at 120 h after IVF. Increasingembryo density resulted in a significant (P < 0.05) increasein the number of cells per blastocyst. In contrast, the cellnumber of IVF embryos that developed to blastocyst decreasedsignificantly (P < 0.05) when they were cultured with unfertilizedoocytes. The results suggest that in-vitro development of IVFmouse embryos is enhanced by increasing embryo density and isimpaired by co-culture with unfertilized (degenerating) oocytes.     

Blood supply to the retina and the lens in the gerbil (<Emphasis Type="Italic">Meriones unguiculatus</Emphasis>)

The blood supply to the retina and the lens in 32 gerbils (Meriones unguiculatus) of both sexes from infancy to maturity was studied under light and stereoscopic microscopes, and a scanning electron microscope. Mercox (CL-2R; Dai Nippon Ink, Tokyo, Japan) was injected into the left ventricle of 30 animals in order to visualize the blood supply to the retina and the lens from the ophthalmic artery. The central retinal artery arises from the ophthalmic artery, passes through the papilla of the optic nerve together with the central retinal vein and penetrates the vitreous space (cavity of the eye) between the lens and the internal limiting membrane of the retina, where it divides into the central branches covering the lens and the parietal branches to supply the retina. The former passes through the hyaloid space after branching several arterioles and then covers the lens like a network from its medial and marginal sides. Different from small experimental animals, the parietal branches, just after separating from the central one, divides into the nasal, dorsal and temporal branches in the vitreous space, each of which then subdivides to distribute across the retina on the inner limiting membrane, then delineates the membrana vasculosa retinae. This basal pattern of vasculization 1 day after birth continues to death. Both the central and parietal branches of the central retinal artery correspond to the branches of the hyaloid artery in embryo and the latter is preserved in adult gerbils.