Chemoresistance is a poor prognostic factor in breast cancer and is a major obstacle to the successful treatment of patients receiving chemotherapy. However, the precise mechanism of resistance remains unclear. In this study, a pair of breast cancer cell lines, MCF-7 and its adriamycin-resistant counterpart MCF-7/ADR was used to examine resistance-dependent cellular responses and to identify potential therapeutic targets. We applied nanoflow liquid chromatography (nLC) and tandem mass tags (TmT) quantitative mass spectrometry to distinguish the differentially expressed proteins (DEPs) between the two cell lines. Bioinformatics analyses were used to identify functionally active proteins and networks. 80 DEPs were identified with either up- or down-regulation. Basing on the human protein-protein interactions (PPI), we have retrieved the associated functional interaction networks for the DEPs and analyzed the biological functions. Six different signaling pathways and most of the DEPs strongly linked to chemoresistance, invasion, metastasis development, proliferation, and apoptosis. The identified proteins in biological networks served to resistant drug and to select critical candidates for validation analyses by western blot. The glucose-6-phosphate dehydrogenase (G6PD), gamma-glutamyl cyclotransferase (GGCT), isocitrate dehydrogenase 1 (NADP+,soluble)(IDH1), isocitrate dehydrogenase 2 (NADP+,mitochondrial) (IDH2) and glutathione S-transferase pi 1(GSTP1), five of the critical components of GSH pathway, contribute to chemoresistance.
Investigating the endophytic bacterial community in special moss species is fundamental to understanding the microbial-plant interactions and discovering the bacteria with stresses tolerance. Thus, the community structure of endophytic bacteria in the xerophilous moss Grimmia montana were estimated using a 16S rDNA library and traditional cultivation methods. In total, 212 sequences derived from the 16S rDNA library were used to assess the bacterial diversity. Sequence alignment showed that the endophytes were assigned to 54 genera in 4 phyla (Proteobacteria, Firmicutes, Actinobacteria and Cytophaga/Flexibacter/Bacteroids). Of them, the dominant phyla were Proteobacteria (45.9%) and Firmicutes (27.6%), the most abundant genera included Acinetobacter, Aeromonas, Enterobacter, Leclercia, Microvirga, Pseudomonas, Rhizobium, Planococcus, Paenisporosarcina and Planomicrobium. In addition, a total of 14 species belonging to 8 genera in 3 phyla (Proteobacteria, Firmicutes, Actinobacteria) were isolated, Curtobacterium, Massilia, Pseudomonas and Sphingomonas were the dominant genera. Although some of the genera isolated were inconsistent with those detected by molecular method, both of two methods proved that many different endophytic bacteria coexist in G. montana. According to the potential functional analyses of these bacteria, some species are known to have possible beneficial effects on hosts, but whether this is the case in G. montana needs to be confirmed.
bacterial diversity; endophytes; moss; molecular method; cultivated isolates
Background. Laparoscopic cyst excision and Roux-en-Y hepaticojejunostomy for treating congenital choledochal cysts (CCCs) have proved to be efficacious in children. Its safety and efficacy in adult patients remain unknown. The purpose of this study was to determine whether the laparoscopic procedure was feasible and safe in adult patients. Methods. We reviewed 35 patients who underwent laparoscopic operation (laparoscopic group) and 39 patients who underwent an open procedure (open group). The operative time, intraoperative blood loss, time until bowel motion recovery, duration of drainage, postoperative stay, time until resumption of diet, postoperative complications, and perioperative laboratory values were recorded and analyzed in both groups. Results. The operative time was longer in the laparoscopic group and decreased significantly with accumulating surgical experience (P < 0.01). The mean intraoperative blood loss was significantly lower in the laparoscopic group (P < 0.01). The time until bowel peristalsis recovery, time until resumption of diet, abdominal drainage, and postoperative stay were significantly shorter in the laparoscopic group (P < 0.01). The postoperative complication rate was not higher in the laparoscopic group than in the open group (P > 0.05). Conclusions. Laparoscopic cyst excision and hepaticojejunostomy are a feasible, effective, and safe method for treating CCCs in adult patients.
AIM: To evaluate human gastric submucosal vascular dysfunction and its mechanism during the aging process.
METHODS: Twenty male patients undergoing subtotal gastrectomy were enrolled in this study. Young and elderly patient groups aged 25-40 years and 60-85 years, respectively, were included. Inclusion criteria were: no clinical evidence of cardiovascular, renal or diabetic diseases. Conventional clinical examinations were carried out. After surgery, gastric submucosal arteries were immediately dissected free of fat and connective tissue. Vascular responses to acetylcholine (ACh) and sodium nitroprusside (SNP) were measured by isolated vascular perfusion. Morphological changes in the gastric mucosal vessels were observed by hematoxylin and eosin (HE) staining and Verhoeff van Gieson (EVG) staining. The expression of xanthine oxidase (XO) and manganese-superoxide dismutase (Mn-SOD) was assessed by Western blotting analysis. The malondialdehyde (MDA) and hydrogen peroxide (H2O2) content and the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were determined according to commercial kits.
RESULTS: The overall structure of vessel walls was shown by HE and EVG staining, respectively. Disruption of the internal elastic lamina or neointimal layers was not observed in vessels from young or elderly patients; however, cell layer number in the vessel wall increased significantly in the elderly group. Compared with submucosal arteries in young patients, the amount of vascular collagen fibers, lumen diameter and media cross-sectional area were significantly increased in elderly patients. Ach- and SNP-induced vasodilatation in elderly arterioles was significantly decreased compared with that of gastric submucosal arterioles from young patients. Compared with the young group, the expression of XO and the contents of MDA and H2O2 in gastric submucosal arterioles were increased in the elderly group. In addition, the expression of Mn-SOD and the activities of SOD and GSH-Px in the elderly group decreased significantly compared with those in the young group.
CONCLUSION: Gastric vascular dysfunction and senescence may be associated with increased oxidative stress and decreased antioxidative defense in the aging process.
Aging; Vascular dysfunction; Gastric blood flow; Oxidative stress; Human
Twelve cDNA libraries from two species of catfish have been sequenced, resulting in the generation of nearly 500,000 ESTs.
Through the Community Sequencing Program, a catfish EST sequencing project was carried out through a collaboration between the catfish research community and the Department of Energy's Joint Genome Institute. Prior to this project, only a limited EST resource from catfish was available for the purpose of SNP identification.
A total of 438,321 quality ESTs were generated from 8 channel catfish (Ictalurus punctatus) and 4 blue catfish (Ictalurus furcatus) libraries, bringing the number of catfish ESTs to nearly 500,000. Assembly of all catfish ESTs resulted in 45,306 contigs and 66,272 singletons. Over 35% of the unique sequences had significant similarities to known genes, allowing the identification of 14,776 unique genes in catfish. Over 300,000 putative SNPs have been identified, of which approximately 48,000 are high-quality SNPs identified from contigs with at least four sequences and the minor allele presence of at least two sequences in the contig. The EST resource should be valuable for identification of microsatellites, genome annotation, large-scale expression analysis, and comparative genome analysis.
This project generated a large EST resource for catfish that captured the majority of the catfish transcriptome. The parallel analysis of ESTs from two closely related Ictalurid catfishes should also provide powerful means for the evaluation of ancient and recent gene duplications, and for the development of high-density microarrays in catfish. The inter- and intra-specific SNPs identified from all catfish EST dataset assembly will greatly benefit the catfish introgression breeding program and whole genome association studies.
Mitochondrial fusion is a highly coordinated process that mixes and unifies the mitochondrial compartment for normal mitochondrial functions and mitochondrial DNA inheritance. Dysregulated mitochondrial fusion causes mitochondrial fragmentation, abnormal mitochondrial physiology and inheritance, and has been causally linked with a number of neuronal diseases. Here, we identified a diterpenoid derivative 15-oxospiramilactone (S3) that potently induced mitochondrial fusion to restore the mitochondrial network and oxidative respiration in cells that are deficient in either Mfn1 or Mfn2. A mitochondria-localized deubiquitinase USP30 is a target of S3. The inhibition of USP30 by S3 leads to an increase of non-degradative ubiquitination of Mfn1/2, which enhances Mfn1 and Mfn2 activity and promotes mitochondrial fusion. Thus, through the use of an inhibitor of USP30, our study uncovers an unconventional function of non-degradative ubiquitination of Mfns in promoting mitochondrial fusion.
mitochondrial fusion; mitofusin1/2; deubiquitinase USP30; 15-Oxospiramilactone
The crystallization of 2-aminophenol 1,6-dioxygenase in complexes with its substrate and with an inhibitor is reported.
Dioxygen activation implemented by nonhaem FeII enzymes containing the 2-His-1-carboxylate facial triad has been extensively studied in recent years. Extradiol dioxygenase is the archetypal member of this superfamily and catalyzes the oxygenolytic ring opening of catechol analogues. Here, the crystallization and preliminary X-ray analysis of 2-aminophenol 1,6-dioxygenase, an enzyme representing a minor subset of extradiol dioxygenases that catalyze the fission of 2-aminophenol rather than catecholic compounds, is reported. Crystals of the holoenzyme with FeII and of complexes with the substrate 2-aminophenol and the suicide inhibitor 4-nitrocatechol were grown using the cocrystallization method under the same conditions as used for the crystallization of the apoenzyme. The crystals belonged to space group C2 and diffracted to 2.3–2.7 Å resolution; the crystal that diffracted to the highest resolution had unit-cell parameters a = 270.24, b = 48.39, c = 108.55 Å, β = 109.57°. All X-ray data sets collected from diffraction-quality crystals were suitable for structure determination.
2-aminophenol 1,6-dioxygenase; extradiol dioxygenases; 2-aminophenol; catechol
Gold nanoparticles (GNPs) can potentially be used in biomedical fields ranging from therapeutics to diagnostics, and their use will result in increased human exposure. Many studies have demonstrated that GNPs can be deposited in the kidneys, particularly in renal tubular epithelial cells. Chronic hypoxic is inevitable in chronic kidney diseases, and it results in renal tubular epithelial cells that are susceptible to different types of injuries. However, the understanding of the interactions between GNPs and hypoxic renal tubular epithelial cells is still rudimentary. In the present study, we characterized the cytotoxic effects of GNPs in hypoxic renal tubular epithelial cells.
Both 5 nm and 13 nm GNPs were synthesized and characterized using various biophysical methods, including transmission electron microscopy, dynamic light scattering, and ultraviolet–visible spectrophotometry. We detected the cytotoxicity of 5 and 13 nm GNPs (0, 1, 25, and 50 nM) to human renal proximal tubular cells (HK-2) by Cell Counting Kit-8 assay and lactate dehydrogenase release assay, but we just found the toxic effect in the 5 nm GNP-treated cells at 50 nM dose under hypoxic condition. Furthermore, the transmission electron microscopy images revealed that GNPs were either localized in vesicles or free in the lysosomes in 5 nm GNPs-treated HK-2 cells, and the cellular uptake of the GNPs in the hypoxic cells was significantly higher than that in normoxic cells. In normoxic HK-2 cells, 5 nm GNPs (50 nM) treatment could cause autophagy and cell survival. However, in hypoxic conditions, the GNP exposure at the same condition led to the production of reactive oxygen species, the loss of mitochondrial membrane potential (ΔΨM), and an increase in apoptosis and autophagic cell death.
Our results demonstrate that renal tubular epithelial cells presented different responses under normoxic and hypoxic environments, which provide an important basis for understanding the risks associated with GNP use–especially for the potential GNP-related therapies in chronic kidney disease patients.
gold nanoparticles (GNPs); toxicity; autophagy; apoptosis
Human induced pluripotent stem cells (iPSCs) hold great promise for regenerative medicine. Generating iPSCs from immunologically immature newborn umbilical cord blood mononuclear cells (UCBMCs) is of great significance. Here we report generation of human iPSCs with great efficiency from UCBMCs using a dox-inducible lentiviral system carrying four Yamanaka factors. We generated these cells by optimizing the existing iPSC induction protocol. The UCBMC-derived iPSCs (UCB-iPSCs) have characteristics that are identical to pluripotent human embryonic stem cells (hESCs). This study highlights the use of UCBMCs to generate highly functional human iPSCs that could accelerate the development of cell-based regenerative therapy for patients suffering from various diseases.
Human UCBMCs; Human iPSCs; Dox-inducible lentiviral system
To evaluate the application of immediate breast reconstruction (IBR) with silicon prosthetic implantation following bilateral nipple-preserving subcutaneous mammary gland excision in the treatment of young patients with early breast cancer.
We retrospectively analyzed the clinical data of 21 patients with breast cancer who were performed on IBR following bilateral nipple-preserving subcutaneous mammary gland excision in our hospital from January 2006 to March 2011.
The operations were successful in all the 21 patients. Also, the treatment provided a good cosmetic effect. No local recurrence or distant metastasis was found in these 21 patients during the 6-66-month follow-up.
For the young patients with early breast cancer, mammary gland excision on the affected side along with prophylactic excision of the contralateral side, namely IBR following bilateral nipple-preserving subcutaneous mammary gland excision, provides good clinical effectiveness and cosmetological effects.
Breast cancer; prophylactic mastectomy; immediate breast reconstruction
Cerebral ischemia is the most common cerebrovascular disease worldwide. Recent studies have demonstrated that curcumin had beneficial effect to attenuate cerebral ischemic injury. However, it is unclear how curcumin protects against cerebral ischemic injury. In the present study, using rat middle cerebral artery occlusion model, we found that curcumin was a potent PPARγ agonist in that it upregulated PPARγ expression and PPARγ-PPRE binding activity. Administration of curcumin markedly decreased the infarct volume, improved neurological deficits, and reduced neuronal damage of rats. In addition, curcumin suppressed neuroinflammatory response by decreasing inflammatory mediators, such as IL-1β, TNF-α, PGE2, NO, COX-2, and iNOS induced by cerebral ischemia of rats. Furthermore, curcumin suppressed IκB degradation that was caused by cerebral ischemia. The present data also showed that PPARγ interacted with NF-κB-p65 and thus inhibited NF-κB activation. All the above protective effects of curcumin on cerebral ischemic injury were markedly attenuated by GW9662, an inhibitor of PPARγ. Our results as described above suggested that PPARγ induced by curcumin may play a critical role in protecting against brain injury through suppression of inflammatory response. It also highlights the potential of curcumin as a therapeutic agent against cerebral ischemia.
Multipotent neural stem/progenitor cells hold great promise for cell therapy. The reprogramming of fibroblasts to induced pluripotent stem cells as well as mature neurons suggests a possibility to convert a terminally differentiated somatic cell into a multipotent state without first establishing pluripotency. Here, we demonstrate that Sertoli cells derived from mesoderm can be directly converted into a multipotent state that possesses neural stem/progenitor cell properties. The induced neural stem/progenitor cells (iNSCs) express multiple NSC-specific markers, exhibit a global gene-expression profile similar to normal NSCs, and are capable of self-renewal and differentiating into glia and electrophysiologically functional neurons. iNSC-derived neurons stain positive for tyrosine hydroxylase (TH), γ-aminobutyric acid, and choline acetyltransferase. In addition, iNSCs can survive and generate synapses following transplantation into the dentate gyrus. Generation of iNSCs may have important implications for disease modeling and regenerative medicine.
direct conversion; neural stem cell; multipotent; transdifferentiation; transplantation
Ovarian cancer is the most common cause of death from gynecologic malignancy. Deregulation of p53 and/or p73-associated apoptotic pathways contribute to the platinum-based resistance in ovarian cancer. NOXA, a pro-apoptotic BH3-only protein, is identified as a transcription target of p53 and/or p73. In this study, we found that genetic variants of Bcl-2 proteins exist among cisplatin-sensitive and -resistant ovarian cancer cells, and the responses of NOXA and Bax to cisplatin are regulated mainly by p53. We further evaluated the effect of NOXA on cisplatin. NOXA induced apoptosis and sensitized A2780s and SKOV3 cells to cisplatin in vitro and in vivo. The effects were mediated by elevated Bax expression, enhanced caspase activation, release of Cyt C and Smac into the cytosol. Furthermore, gene silencing of Bax or Smac significantly attenuated NOXA and/or cisplatin-induced apoptosis in chemosensitive A2780s cells, whereas overexpression of Bax or addition of Smac-N7 peptide significantly increased NOXA and/or cisplatin-induced apoptosis in chemoresistant SKOV3 cells. To our knowledge, these data suggest a new mechanism by which NOXA chemosensitized ovarian cancer cells to cisplatin by inducing alterations in the Bax/Smac axis. Taken together, our findings show that NOXA is potentially useful as a chemosensitizer in ovarian cancer therapy.
Vaccinia Tian Tan (VTT) was attenuated by deletion of the TC7L-TK2L and TA35R genes to generate MVTT3. The mutant was generated by replacing the open reading frames by a gene encoding enhanced green fluorescent protein (EGFP) flanked by loxP sites. Viruses expressing EGFP were then screened for and purified by serial plaque formation. In a second step the marker EGFP gene was removed by transfecting cells with a plasmid encoding cre recombinase and selecting for viruses that had lost the EGFP phenotype. The MVTT3 mutant was shown to be avirulent and immunogenic. These results support the conclusion that TC7L-TK2L and TA35R deletion mutants can be used as safe viral vectors or as platform for vaccines.
In the title molecule, C17H20ClNOS2, the phenyl and oxazole rings are nearly coplanar with an average deviation of 0.022 Å from the mean plane (M). The 1,3-dithiane ring adopts a chair conformation and is twisted in such a way that the C—CBu fragment lies in M (deviations are 0.031 and 0.010 Å, respectively, for the two C atoms).
Parkinson’s disease (PD) is a neurodegenerative disorder characterized by loss of dopaminergic neurons. Dysregulation of mammalian target of rapamycin (mTOR) has been implicated in the pathogenesis of PD. However, the underlying mechanism is incompletely elucidated. Here, we show that PD mimetics (6-hydroxydopamine, N-methyl-4-phenylpyridine or rotenone) suppressed phosphorylation of mTOR, S6K1 and 4E-BP1, reduced cell viability, and activated caspase-3 and PARP in PC12 cells and primary neurons. Overexpression of wild-type mTOR or constitutively active S6K1, or downregulation of 4E-BP1 in PC12 cells partially prevented cell death in response to the PD toxins, revealing that mTOR-mediated S6K1 and 4E-BP1 pathways due to the PD toxins were inhibited, leading to neuronal cell death. Furthermore, we found that the inhibition of mTOR signaling contributing to neuronal cell death was attributed to suppression of Akt and activation of AMPK. This is supported by the findings that ectopic expression of constitutively active Akt or dominant negative AMPKα, or inhibition of AMPKα with compound C partially attenuated inhibition of phosphorylation of mTOR, S6K1 and 4E-BP1, activation of caspase-3, and neuronal cell death triggered by the PD toxins. The results indicate that PD stresses activate AMPK and inactivate Akt, causing neuronal cell death via inhibiting mTOR-mediated S6K1 and 4E-BP1 pathways. Our findings suggest that proper co-manipulation of AMPK/Akt/mTOR signaling may be a potential strategy for prevention and treatment of PD.
AMPK; Akt; mTOR; neuronal cells; Parkinson’s disease
Several epidemiological studies have found a positive association between diabetic retinopathy (DR) and subclinical hypothyroidism (SCH), but the findings are varied or even contradictory. In the work, we performed a meta-analysis to ascertain the relationship between DR and SCH. We searched relevant studies on the relationship between DR and SCH. All English reports were used Medline, EMbase, Web of Science, Google scholar, and all Chinese ones used CBMDisc (Chinese Biochemical Literature on Disc) and CNKI (China National Knowledge Infrastructure) database. Meta-analysis was performed using RevMan 5.1 software. We obtained eight observational studies. Random-effects meta-analysis indicated a significant association between DR and SCH (odds ratio = 2.13, 95% confidence interval = 1.41 – 3.23, p < 0.001). Based on currently evidence, SCH is probably a significant risk factor for DR.
Sex-biased genes are considered to account for most of phenotypic differences between males and females. In order to explore the sex-biased gene expression in crab, we performed the whole-body transcriptome analysis in male and female juveniles of the Chinese mitten crab Eriocheir sinensis using next-generation sequencing technology. Of the 23,349 annotated unigenes, 148 were identified as sex-related genes. A total of 29 candidate genes involved in primary sex determination pathways were detected, indicating the sex determination cascade of the mitten crab might be more complex than previously supposed. Differential expression analysis showed 448 differentially expressed genes (DEGs) between the two transcriptomes. Most of DEGs were involved in processes such as metabolism and immunity, and not associated with obvious sexual function. The pathway predominantly enriched for DEGs were related to lysosome, which might reflect the differences in metabolism between males and females. Of the immune DGEs, 18 up-regulated genes in females were humoral immune factors, and eight up-regulated genes in males were pattern recognition receptors, suggesting sex differences of immune defense might exist in the mitten crab. In addition, two reproduction-related genes, vitellogenin and insulin-like androgenic gland factor, were identified to express in both sexes but with significantly higher level in males. Our research provides the first whole-body RNA sequencing of sex-specific transcriptomes for juvenile E. sinensis and will facilitate further studies on molecular mechanisms of crab sexual dimorphism.
Increasing atmospheric nitrogen (N) deposition could profoundly impact community structure and ecosystem functions in forests. However, conventional experiments with understory addition of N (UAN) largely neglect canopy-associated biota and processes and therefore may not realistically simulate atmospheric N deposition to generate reliable impacts on forest ecosystems. Here we, for the first time, designed a novel experiment with canopy addition of N (CAN) vs. UAN and reviewed the merits and pitfalls of the two approaches. The following hypotheses will be tested: i) UAN overestimates the N addition effects on understory and soil processes but underestimates those on canopy-associated biota and processes, ii) with low-level N addition, CAN favors canopy tree species and canopy-dwelling biota and promotes the detritus food web, and iii) with high-level N addition, CAN suppresses canopy tree species and other biota and favors rhizosphere food web. As a long-term comprehensive program, this experiment will provide opportunities for multidisciplinary collaborations, including biogeochemistry, microbiology, zoology, and plant science to examine forest ecosystem responses to atmospheric N deposition.
mTOR is a central controller for cell growth/proliferation and survival. Recent studies have shown that mTOR also regulates cell adhesion, yet the underlying mechanism is not known. Here we found that inhibition of mTOR by rapamycin reduced the basal or type I insulin-like growth factor (IGF-1)-stimulated adhesion of cancer cells. Further research revealed that both mTORC1 and mTORC2 were involved in the regulation of cell adhesion, as silencing expression of raptor or rictor inhibited cell adhesion. Also, PP242, an mTORC1/2 kinase inhibitor, inhibited cell adhesion more potently than rapamycin (mTORC1 inhibitor). Of interest, ectopic expression of constitutively active and rapamycin-resistant mutant of p70 kinase 1 (S6K1) or downregulation of eukaryotic initiation factor 4E (eIF4E)-binding protein 1 (4E-BP1) conferred resistance to rapamycin inhibition of cell adhesion, whereas expression of constitutively hypophosphorylated 4E-BP1 (4EBP1-5A) or downregulation of S6K1 suppressed cell adhesion. In contrast, neither genetic manipulation of Akt activity nor pharmacological inhibition of Akt affected cell adhesion. The results suggest that both mTORC1 and mTORC2 are involved in the regulation of cell adhesion; and mTORC1 regulates cell adhesion through S6K1 and 4E-BP1 pathways, but mTORC2 regulates cell adhesion via Akt-independent mechanism.
rapamycin; mTOR; cell adhesion; Akt; 4E-BP1
To evaluate the prevalence and risk factors of diabetes and diabetic retinopathy (DR) in northeast area of China with a population-based study.
A population of 3173 (aged from 20 to 80 years old) was stratified by geographical location and age in Liaoning province, China. Prediabetes and diabetes were diagnosed according to the guideline of American Diabetes Association. Retinal photographs were obtained by using digital non-mydriatic camera for the presence and grading of DR according to the modified ETDRS Airlie house classification. Blood samples and comprehensive questionnaires were obtained for evaluation of laboratory results and risk factors.
The prevalence of prediabetes and diabetes was 20.7% and 10.4%, respectively. Among diabetes patients, DR prevalence was 11.9%. Age, obesity, total cholesterol, triglycerides, hypertension, living in rural areas and diabetes family history are all risk factors for prediabetes and diabetes. Waist-to-hip circumference rate served as a better obesity index to estimate diabetes risk compared with body mass index and waist circumference. Among all risk factors that we investigated, only the length of diabetes history was associated with the incidence of DR. However, DR prevalence in the newly discovered patients in rural areas was significantly higher than that in urban areas.
According to this study, 1 in 10 people has diabetes, 2 in 10 people have prediabetes, and 1 in 10 diabetics has DR in Liaoning province. In rural areas, diabetes was poorly recognized with limited medical resources, which probably resulted in more diabetes patient at a high risk of DR.