PubMed Health⌕ Search

Biomedical subjects

Peng Chen

Publications and source records attributed to Peng Chen.

At least 37 records · Page 2Linked to original sources

A "gain of function" mutation in a protein mediates production of novel modified nucleosides.

The mutation sufY204 mediates suppression of a +1 frameshift mutation in the histidine operon of Salmonella enterica serovar Typhimurium and synthesis of two novel modified nucleosides in tRNA. The sufY204 mutation, which results in an amino-acid substitution in a protein, is, surprisingly, dominant over its wild-type allele and thus it is a "gain of function" mutation. One of the new nucleosides is 5-methylaminomethyl-2-thiouridine (mnm(5)s(2)U34) modified by addition of a C(10)H(17) side chain of unknown structure. Increased amounts of both nucleosides in tRNA are correlated to gene dosage of the sufY204 allele, to an increased efficiency of frameshift suppression, and to a decreased amount of the wobble nucleoside mnm(5)s(2)U34 in tRNA. Purified tRNA(Gln)(cmnm(5)s(2)UUG) in the mutant strain contains a modified nucleoside similar to the novel nucleosides and the level of aminoacylation of tRNA(Gln)(cmnm(5)s(2)UUG) was reduced to 26% compared to that found in the wild type (86%). The results are discussed in relation to the mechanism of reading frame maintenance and the evolution of modified nucleosides in tRNA.

Amino Acid Substitution↗

The Genomes of Oryza sativa: a history of duplications.

We report improved whole-genome shotgun sequences for the genomes of indica and japonica rice, both with multimegabase contiguity, or almost 1,000-fold improvement over the drafts of 2002. Tested against a nonredundant collection of 19,079 full-length cDNAs, 97.7% of the genes are aligned, without fragmentation, to the mapped super-scaffolds of one or the other genome. We introduce a gene identification procedure for plants that does not rely on similarity to known genes to remove erroneous predictions resulting from transposable elements. Using the available EST data to adjust for residual errors in the predictions, the estimated gene count is at least 38,000-40,000. Only 2%-3% of the genes are unique to any one subspecies, comparable to the amount of sequence that might still be missing. Despite this lack of variation in gene content, there is enormous variation in the intergenic regions. At least a quarter of the two sequences could not be aligned, and where they could be aligned, single nucleotide polymorphism (SNP) rates varied from as little as 3.0 SNP/kb in the coding regions to 27.6 SNP/kb in the transposable elements. A more inclusive new approach for analyzing duplication history is introduced here. It reveals an ancient whole-genome duplication, a recent segmental duplication on Chromosomes 11 and 12, and massive ongoing individual gene duplications. We find 18 distinct pairs of duplicated segments that cover 65.7% of the genome; 17 of these pairs date back to a common time before the divergence of the grasses. More important, ongoing individual gene duplications provide a never-ending source of raw material for gene genesis and are major contributors to the differences between members of the grass family.

Base Sequence↗

Intraoperative awakening for vision examination during ophthalmic artery aneurysm clipping: technical case report.

OBJECTIVE AND IMPORTANCE: We present a case of a patient with an ophthalmic artery aneurysm in which the ophthalmic artery originated from the body of the aneurysm, requiring sacrifice of the ophthalmic artery to achieve complete aneurysm obliteration. We awakened the patient intraoperatively to assess optic nerve function after clipping and were able to confirm optic nerve function. Controlled intraoperative awakening proved a valuable adjunct to intraoperative angiography in determining the immediate consequences of sacrifice of the ophthalmic artery. CLINICAL PRESENTATION: The patient was a 55-year-old right-handed woman with a 3-month history of episodic blurriness in her left eye; imaging demonstrated an unruptured 5-mm left ophthalmic artery aneurysm in which the ophthalmic artery originated from the body of the aneurysm. INTERVENTION: Complete obliteration of the aneurysm required clip placement across the neck of the aneurysm, incorporating not only the aneurysm but also the ophthalmic artery. Aware that sacrifice of the ophthalmic artery was likely, we awakened the patient after clipping and before dural closure to evaluate her optic nerve function. Once fully awake, the patient was able to execute simple commands and conclusively confirm light perception in both of her eyes. She was then reanesthetized, and intraoperative angiography showed successful aneurysm obliteration and parent artery patency. CONCLUSION: The ophthalmic artery can be sacrificed during aneurysm clipping without loss of vision in many cases, most likely because of adequate collateral filling from the external carotid artery. Certainty about the visual consequences of sacrifice of the ophthalmic artery, however, is difficult to obtain preoperatively or intraoperatively. Intraoperative awakening for evaluation of optic nerve function served as a useful technique to assess the acute results of interruption of ophthalmic artery flow in this case.

Aneurysm↗

Immortalization of human umbilical vein endothelial cells with telomerase reverse transcriptase and simian virus 40 large T antigen.

OBJECTIVE: To establish normally conditionally-immortalized human umbilical vein endothelial cells (HUVECs) by ectopic expression of the human telomerase catalytic enzyme (hTERT) and simian virus 40 large T (SV40 LT) antigen. METHODS: Primary HUVECs were transfected with recombinant retrovirus containing hTERT or SV40 LT respectively. Subsequently drug resistant cell clones were screened and expanded for further studies. Endothelial cell biomarkers were confirmed by examination. RESULTS: The morphological phenotype of the transfected cells was similar to the non-transfected cells. Von Willebrand factor, hTERT and SV40 LT could be detected in transfected HUVECs. Moreover, higher telomerase activity in transfected cells was maintained for over 50 population doublings compared with only low level of endogenous telomerase transiently at early population doublings in primary HUVECs. When exposed to TNF-alpha (tumor necrosis factor-alpha), the expression of E-selectin in transfected cells was significantly up-regulated, but no alteration of endothelial lipase was found. CONCLUSION: Ectopic coexpression of hTERT and SV40 LT can effectively immortalize HUVECs without tumorigenicity in vitro. Immortalized HUVECs may be an ideal target of further molecular function studies.

Antigens, Polyomavirus Transforming↗

[Immortalization of human umbilical vein endothelial cells by transfected with hTERT and SV40LT].

OBJECTIVE: To immortalize human umbilical vein endothelial cells (HUVECs) by ectopic expression of the telomerase reverse transcriptase enzyme (hTERT), and by Simian Virus 40 Large T (SV40LT) antigen without malignant transformation. METHODS: Two different retroviruses that contained hTERT/SV40LT cDNA fragment and drug resistance gene were constructed, and were used to transfect normal primary HUVECs. The transfected cells were screened with 500 microg/ml G418 and 4 microg/ml puromycin. Drug resistance cell clones were selected 3 days after transfection and cultured for further studies. An under inverted microscope and a scanning electron microscope were used to observe the morphology and growth of the cells. The expression of VIII factor and transfected DNA fragments were detected for identification of the endothelial origin and successful transfection. And the expression of E-selectin and endothelial lipase with or without the stimulus of TNF-alpha were also assayed to analyze the biological activity of the transfected cells. RESULTS: The cells were homogenous, closely apposed, large, flat, and polygonal, displayed a characteristic ovoid nucleus with one or two nucleoli and formed monolayer with polygonal shape without overlapping. Immunocytochemical staining showed the existence of VIII factor. SV40LT/hTERT antigen expressed by the transfected cells was detected, while the contrasts had non-expression. Telomerase activity of the cell was detected in the transfected cells, which was 0.36 at 12 th passage and 0.38 at 50 th passage. However, the activity in the normal HUVECs was 1.12 at the first passage and 0.06 at the third passage assayed by PCR-ELISA. Both E-selectin and endothelial lipase were all specific in endothelial cells. The expressions of these two were also detected. And the expression of E-selectin can be up-regulated with the stimulus of TNF-alpha, while the expression of endothelial lipase was not unregulated significantly. CONCLUSION: Ectopic expression of hTERT and SV40LT can effectively immortalize HUVECs without tumorigenesis.

Antigens, Polyomavirus Transforming↗

[The significance of Th1/Th2 function imbalance in patients with post-infarction cardiac insufficiency].

OBJECTIVE: To study the significance of Th1/Th2 function imbalance in patients with post-infarction cardiac insufficiency. METHODS: Forty-three MI (myocardial infarction) patients were divided into 2 groups one month after the onset according to the New York Heart Association (NYHA) classification system: group MI 1 (I, II) 25 patients and group MI 2 (III, IV) 18 patients. At the same time, the heart function was evaluated by two-dimensional echocardiography. Peripheral blood mononuclear cells (PBMCs) were collected from these patients. Cytokine-producing CD4 + T cells were quantified by 3-color flow cytometry after being stimulated with phorbol myristate acetate (PMA) and ionomycin. After being stimulated with PHA, the levels of IFN-gamma and IL-4 in culture supernatants were measured by ELISA. RESULTS: The frequencies of IFN-gamma-producing T cells were found to be significantly higher in group MI 2 (16.8%) than that in group MI 1 (13.1%). There was no significant difference on the frequencies of IL-4-producing peripheral T cells between the two groups. The IFN-gamma level and the ratios of IFN-gamma/IL-4 in group MI 2 were significantly higher than those in group MI 1, while there was no significant difference in IL-4 levels between the two groups. CONCLUSIONS: The Th-cell function was associated with heart function in post MI patients. The up-regulation of Th1 cell function was consistent with poor heart function, suggesting that Th1/Th2 cell function imbalance may participate in ventricular remodelling after MI.

Aged↗

Role of donor-derived monocyte chemoattractant protein-1 in murine islet transplantation.

Monocyte chemoattractant protein-1 (CCL2/MCP-1) is a proinflammatory chemokine produced by several cell types, including pancreatic islets. High levels of donor-derived CCL2 have been associated with poor islet allograft outcome in patients with type 1 diabetes; however, the causal relationship is unknown. The constitutive and inducible expression of chemokines and their receptors by pancreatic islets in vitro were investigated, specifically the role of donor-derived CCL2 in marginal mass murine islet transplantation. The results showed that inflammatory cytokine stimulation of islets induced de novo expression of CCL2, CCL5/RANTES, CXCL9/MIG, and CXCL10/IP-10 and increased expression of CXCL2/macrophage-inflammatory protein-2. CCL2 mRNA and protein were highly expressed within 2 d in cultures. Transplantation of islets with high levels of CCL2 into syngeneic recipients led to a significantly greater influx of CCR2(+) cells and higher expression of monocyte/macrophage-associated inflammatory cytokines compared with low CCL2-donor islets. The level of pretransplantation CCL2 inversely correlated (P < 0.0001) with isograft function. In contrast, in CCR2-/- recipients, this correlation was not present. A direct toxic effect of CCL2 on islets was excluded by assessing cell viability and insulin release in vitro. In conclusion, CCL2 secreted by islets plays an important role in the immediate islet graft function. Strategies to decrease islet-derived CCL2 release may increase the success of islet transplantation.

Animals↗

O2 activation by binuclear Cu sites: noncoupled versus exchange coupled reaction mechanisms.

Binuclear Cu proteins play vital roles in O(2) binding and activation in biology and can be classified into coupled and noncoupled binuclear sites based on the magnetic interaction between the two Cu centers. Coupled binuclear Cu proteins include hemocyanin, tyrosinase, and catechol oxidase. These proteins have two Cu centers strongly magnetically coupled through direct bridging ligands that provide a mechanism for the 2-electron reduction of O(2) to a mu-eta(2):eta(2) side-on peroxide bridged Cu(II)(2)(O(2)(2-)) species. This side-on bridged peroxo-Cu(II)(2) species is activated for electrophilic attack on the phenolic ring of substrates. Noncoupled binuclear Cu proteins include peptidylglycine alpha-hydroxylating monooxygenase and dopamine beta-monooxygenase. These proteins have binuclear Cu active sites that are distant, that exhibit no exchange interaction, and that activate O(2) at a single Cu center to generate a reactive Cu(II)/O(2) species for H-atom abstraction from the C-H bond of substrates. O(2) intermediates in the coupled binuclear Cu enzymes can be trapped and studied spectroscopically. Possible intermediates in noncoupled binuclear Cu proteins can be defined through correlation to mononuclear Cu(II)/O(2) model complexes. The different intermediates in these two classes of binuclear Cu proteins exhibit different reactivities that correlate with their different electronic structures and exchange coupling interactions between the binuclear Cu centers. These studies provide insight into the role of exchange coupling between the Cu centers in their reaction mechanisms.

Binding Sites↗

[Nuclear factor kappa B signal transduction in macrophages during hypoxia: reactive oxygen species generation].

The effects of hypoxia on the level of reactive oxygen species (ROS), IkappaBalpha tyrosine phosphorylation, transcription of P65 mRNA and NF-kappaB activation in isolated rat peritoneal macrophages were investigated by DCFH-DA fluorescence spectrophotometry, Western blotting and RT-PCR. The results obtained are as follows. (1) During hypoxia, the levels of intracellular ROS began to increase at 1 h, then reached a peak at 2 h, and began to decrease after 3 h. IkappaBalpha tyrosine phosphorylation began to rise after 2 h hypoxia and was the highest after 3 h hypoxia. After 4 h hypoxia it decreased gradually. NF-kappaB activation began to increase after 3 h hypoxia, and reached a peak after 4 h hypoxia. (2) When antioxidant NAC (500 mmol/L) was added into the medium, the level of IkappaBalpha phosphorylation showed no significant changes during hypoxia. After adding protein tyrosine kinase inhibitor genistein (200 micromol/L), NF-kappaB activation induced by hypoxia was blocked significantly. (3) The expression of p65 mRNA was also elevated markedly during hypoxia. These results suggest that hypoxia may lead to IkappaBalpha phosphorylation and NF-kappaB activation through intracellular ROS, and that the regulation of NF-kappaB activity may involve IkappaBalpha phosphorylation and the expressions of each subunit gene of NF-kappaB.

Animals↗

N2O reduction by the mu4-sulfide-bridged tetranuclear CuZ cluster active site.

Nitrous oxide (N2O) reduction is a chemical challenge both in the selective oxidation of organic substrates by N2O and in the removal of N2O as a green-house gas. The reduction of N2O is thermodynamically favorable but kinetically inert, and requires activating transition-metal centers. In biological systems, N2O reduction is the last step in the denitrification process of the bacterial nitrogen cycle and is accomplished by the enzyme nitrous oxide reductase, whose active site consists of a micro4-sulfide-bridged tetranuclear CuZ cluster which has many unusual spectroscopic features. Recent studies have developed a detailed electronic-structure description of the resting CuZ cluster, determined its catalytically relevant state, and provided insight into the role of this tetranuclear copper cluster in N2O activation and reduction.

Binding Sites↗

Role of CaMKII in hydrogen peroxide activation of ERK1/2, p38 MAPK, HSP27 and actin reorganization in endothelial cells.

Growing evidence suggests that reactive oxygen species such as hydrogen peroxide (H(2)O(2)) can function as important signaling molecules in vascular cells. H(2)O(2)-activated redox-sensitive pathways mediate both physiological and pathological responses given the location and concentration of H(2)O(2). We showed previously for the first time that calcium/calmodulin-dependent protein kinase II (CaMKII) is redox-sensitive in endothelial cells, mediating H(2)O(2) upregulation of endothelial nitric oxide synthase. This response is always accompanied by an elongation phenotype of endothelial cells, implying modulation of actin cytoskeleton. In the present study, we investigated the role of CaMKII in H(2)O(2) activation of p38 MAPK/heat shock protein 27 (HSP27) pathway and ERK1/2, both of which have been known to regulate actin reorganization in endothelial cells. Addition of H(2)O(2) to bovine aortic endothelial cells increased ERK1/2 phosphorylation and activity, which was attenuated by a specific inhibitor of CaMKII, KN93. KN93 also prevented H(2)O(2) activation of p38 MAPK. Transfection of endothelial cells with a CaMKII-specific inhibitory peptide (AA 281-309) reduced H(2)O(2) phosphorylation of p38 MAPK and ERK1/2. Furthermore, blockade of CaMKII or janus kinase 2 (JAK2, downstream of CaMKII) prevented H(2)O(2) activation of HSP27. KN93 attenuated, whereas AG490 (JAK2 inhibitor) abolished, H(2)O(2)-induced formation of actin stress fibers. Blockade of ERK1/2 inhibited H(2)O(2) phosphorylation of HSP27 transiently. It also partially prevented H(2)O(2) induction of actin stress fibers. In summary, redox-sensitive activation of p38 MAPK/HSP27 pathway or ERK1/2 in endothelial cells requires CaMKII. These pathways are at least partially responsible for H(2)O(2) induced reorganization of actin cytoskeleton.

Actins↗

Selenium distribution in a Se-enriched mushroom species of the genus Ganoderma.

Data reported here show that Ganoderma lucidum could biotransform inorganic selenite in the substrate into organic forms by intergrating Se into proteins (56-61%) and polysaccharides (11-18%) and other components. Furthermore, water- and alkaline-soluble protein components were mainly responsible for the storage of organic Se, and Se-Met accounts for only a minor (8.2-18.3%) amount of the selenocompounds present in proteins. The molecular mass of most proteins or protein subunits containing Se was no more than 16 kDa. A low concentration of Se (<100 microg/g) in the substrate facilitated the synthesis of total protein and amino acids in G. lucidum, but a high concentration of Se (>150 microg/g) played a reverse role. Additionally, Se concentration in the culture had no significant effect on the distribution of the amino acids and proteins.

Amino Acids↗

Oxygen activation by the noncoupled binuclear copper site in peptidylglycine alpha-hydroxylating monooxygenase. Spectroscopic definition of the resting sites and the putative CuIIM-OOH intermediate.

Spectroscopic methods, density functional calculations, and ligand field analyses are combined to define the geometric models and electronic structure descriptions of the Cu(M) and Cu(H) sites in the oxidized form of the noncoupled binuclear copper protein peptidylglycine alpha-hydroxylating monooxygenase (PHM). The Cu(M) site has a square pyramidal geometry with a long axial Cu-methionine bond and two histidines, H(2)O, and OH(-) as equatorial ligands. The Cu(H) site has a slightly D(2)(d) distorted square planar geometry with three histidines and H(2)O ligands. The structurally inequivalent Cu(M) and Cu(H) sites do not exhibit measurable differences in optical and electron paramagnetic resonance (EPR) spectra, which result from their similar ligand field transition energies and ground-state Cu covalencies. The additional axial methionine ligand interaction and associated square pyramidal distortion of the Cu(M) site have the opposite effect of the strong equatorial OH(-) donor ligand on the Cu d orbital splitting pattern relative to the Cu(H) site leading to similar ligand field transition energies for both sites. The small molecule NO(2)(-) binds in different coordination modes to the Cu(M) and Cu(H) site because of differences in their exchangeable coordination positions resulting in these Cu(II) sites being spectroscopically distinguishable. Azide binding to PHM is used as a spectroscopic and electronic structure analogue to OOH(-) binding to provide a starting point for developing a geometric and electronic structural model for the putative Cu(II)(M)-OOH intermediate in the H-atom abstraction reaction of PHM. Possible electronic structure contributions of the Cu(II)(M)-OOH intermediate to reactivity are considered by correlation to the well-studied L3Cu(II)-OOH model complex (L3 = [HB[3-tBu-5-iPrpz](3)]). The Met-S ligand of the Cu(M) site is found to contribute to the stabilization of the Cu(II)(M)-oxyl species, which would be a product of Cu(II)(M)-OOH H-atom abstraction reaction. This Met-S contribution could have a significant effect on the energetics of a H-atom abstraction reaction by the Cu(II)(M)-OOH intermediate.

Binding Sites↗

Oxygen activation by the noncoupled binuclear copper site in peptidylglycine alpha-hydroxylating monooxygenase. Reaction mechanism and role of the noncoupled nature of the active site.

Reaction thermodynamics and potential energy surfaces are calculated using density functional methods to investigate possible reactive Cu/O(2) species for H-atom abstraction in peptidylglycine alpha-hydroxylating monooxygenase (PHM), which has a noncoupled binuclear Cu active site. Two possible mononuclear Cu/O(2) species have been evaluated, the 2-electron reduced Cu(II)(M)-OOH intermediate and the 1-electron reduced side-on Cu(II)(M)-superoxo intermediate, which could form with comparable thermodynamics at the catalytic Cu(M) site. The substrate H-atom abstraction reaction by the Cu(II)(M)-OOH intermediate is found to be thermodynamically accessible due to the contribution of the methionine ligand, but with a high activation barrier ( approximately 37 kcal/mol, at a 3.0-A active site/substrate distance), arguing against the Cu(II)(M)-OOH species as the reactive Cu/O(2) intermediate in PHM. In contrast, H-atom abstraction from substrate by the side-on Cu(II)(M)-superoxo intermediate is a nearly isoenergetic process with a low reaction barrier at a comparable active site/substrate distance ( approximately 14 kcal/mol), suggesting that side-on Cu(II)(M)-superoxo is the reactive species in PHM. The differential reactivities of the Cu(II)(M)-OOH and Cu(II)(M)-superoxo species correlate to their different frontier molecular orbitals involved in the H-atom abstraction reaction. After the H-atom abstraction, a reasonable pathway for substrate hydroxylation involves a "water-assisted" direct OH transfer to the substrate radical, which generates a high-energy Cu(II)(M)-oxyl species. This provides the necessary driving force for intramolecular electron transfer from the Cu(H) site to complete the reaction in PHM. The differential reactivity pattern between the Cu(II)(M)-OOH and Cu(II)(M)-superoxo intermediates provides insight into the role of the noncoupled nature of PHM and dopamine beta-monooxygenase active sites, as compared to the coupled binuclear Cu active sites in hemocyanin, tyrosinase, and catechol oxidase, in O(2) activation.

Binding Sites↗

Reliability of radiologic assessment of fusion: cervical fibular allograft model.

STUDY DESIGN: Prospective assessment of the reliability of determining cervical fusion success based on plain radiographs. OBJECTIVES: Determination of the reliability of plain static radiographs in predicting the presence or absence of fusion. SUMMARY OF BACKGROUND DATA: The ability of plain radiographs to assess the presence of fusion is limited. In addition, variations in the definition of "fusion" make this entity an important aspect for study. METHODS: A study was carried out to determine the reliability of plain radiographs in predicting bony fusion. Cases of cervical spondylosis undergoing a single or multilevel corpectomy with an allograft fusion and anterior instrumentation were chosen for the model. The definition of "bony fusion" was obtained from the literature. Bony fusion was defined by the presence of bony trabeculation across the graft-host interfaces, the assessment of the change in strut height over time, and the development of a kyphotic angulation over time. Data were collected at a tertiary care institution over a 5-year period. Descriptive statistics regarding baseline patient characteristics, the underlying disease process, and the surgical intervention, were obtained. Reliability of plain static radiographs in assessing fusion was evaluated by two independent neuroradiologists blinded to any subsequent clinical outcome. The Cohen Kappa statistic was used to determine the degree of agreement regarding the presence or absence of fusion at the superior and inferior aspect of the graft at the 6-week and the 12-week follow-up. RESULTS: The study involved 57 patients (30 males and 27 females), with a median age of 49 years. The number of levels decompressed was 1, 2, and 3 in 36, 20, and 1 patients, respectively. Fourteen patients had a history of smoking. The Cohen Kappa statistic revealed variable results depending on the time period and aspect evaluated. The degree of agreement at 6 weeks was 0.61 (95% confidence interval = 0.32-0.89) and 0.44 (95% confidence interval = 0.017-0.86) and at 12 weeks was 0.18 (95% confidence interval = -0.21-0.58) and 1.00 for the superior and inferior aspect of the graft, respectively. CONCLUSIONS: Plain radiographs are generally quite unreliable in predicting fusion based on presence or absence of trabeculation.

Bone Regeneration↗

Differentiation potential of bone marrow mesenchymal stem cells into retina in normal and laser-injured rat eye.

Bone marrow mesenchymal stem cells (MSCs) can develop into hematopoietic and mesenchymal lineages but have not been known to participate in the production of retina. Here we report that bone marrow mesenchymal stem cells, after being subretinally transplanted into normal or Nd: YAG laser-injured rat eye, can integrate into RPE layer, photoreceptor layer, bipolar cell layer and ganglion layer. DAPI-labeling detection was used to trace the origin of the repopulating cells. DAPI fluorescence was used to identify retina cells of bone marrow origin 10, 20, 35 and 50 days after transplantation. No formation of rosettes was found but some random cells were found at the end of the observation. MSCs-originated cells spread more widely in the injured retinas than in the normal ones. Immunohistochemical detection showed that though the cells could express neuronal nuclei (NeuN), neuron specific enolase (NSE), glial fibrillary acidic protein (GFAP) and cytokeratin (CK), the proteins expression in the injured transplantation group was abnormal in some region compared with that in the normal transplantation group. Electroretinogram (ERG) showed that ERG-b wave of the injured transplantation group is significantly higher than that of the two laser-injured control groups. These results suggest that a proportion of MSCs can differentiate into retina-like structure in vivo and the differentiation differs in normal and laser-injured retinas.

Animals↗