Branch retinal artery occlusion in a patient with COVID-19 infection: A case report.

We report here, a case of branch retinal artery occlusion (BRAO) in the left eye of a 76-year-old man that involved three arteries which was considered to be related to a COVID-19 infection due to high levels of blood cytokines and coagulation factors. Although the patient had hypertension and atherosclerosis, his hypertension had been well controlled for the past five years by regular antihypertensive medication. Twenty-five days after starting treatment with anti-inflammatory, anticoagulant and conservative therapy, the patient's biomarkers of inflammation and coagulation returned to normal and his vision improved. However, some visual field defects remained and were probably a consequence of low oxygen saturation.

A Comparison of Growth Performance, Blood Parameters, Rumen Fermentation, and Bacterial Community of Tibetan Sheep When Fattened by Pasture Grazing versus Stall Feeding.

Traditionally, Tibetan sheep only graze pastures without any supplementary feed. However, in recent years, feedlots are being used for fattening Tibetan sheep. The present study compared the growth rates, blood parameters, rumen fermentation, and bacterial communities in Tibetan sheep fattened by pasture grazing (PG) versus those fattened by stall feeding (SF). Twenty 18-month-old Tibetan sheep wethers (42.6 ± 2.11 kg) were divided randomly into PG (n = 10) and SF (n = 10) groups. The PG sheep grazed the grasslands without any supplementary feed, while the SF sheep were offered a commercial total mixed ration (TMR) at a crude protein content of 16.2% DM and an ME of 10.59 MJ/kg. The sheep were on their treatments for 70 days, which included 10 days for adaptation and 60 days for measurements. The average daily gain, white blood cell and lymphocyte counts were greater (p < 0.05), while the platelet count was lower (p < 0.05) in the SF group than in the PG group. The serum glutathione peroxidase activity, and concentrations of total proteins and albumin were greater (p < 0.05), while glucose was lower (p < 0.01) in the PG group compared to the SF group. The concentrations of ruminal ammonia-N and total volatile fatty acids (VFAs) were greater (p < 0.05), while the pH was lower (p < 0.05) in the SF group compared to the PG group. The molar proportion of acetate and the ratio of acetate to propionate were greater (p < 0.01) in the PG sheep than in the SF sheep, but the molar proportion of propionate and iso-VFAs did not differ (p > 0.05) between the groups. Based on the PCoA, the ruminal bacterial communities were distinct between groups, and the alpha diversity was greater (p < 0.001) in the PG sheep than in the SF sheep. The dominant phyla of the rumen bacteria were Firmicutes and Bacteroidetes, while the Firmicutes to Bacteroidetes ratio was greater (p < 0.001) in the SF group than in the PG group. At the genus level, the relative abundance of Ruminococcus was greater (p < 0.05) in the SF group, while the abundances of Prevotella, the Rikenellaceae_RC9_gut_group, Butyrivibrio, and unclassified_f_Lachnospiraceae were greater (p < 0.05) in the PG group. It was concluded that the Tibetan sheep adopted a short-term intensive fattening strategy when stall fed which altered the rumen bacterial community and blood parameters, enhanced rumen fermentation, and, ultimately, improved their average daily gain.

Apoplast-Extraction Based Method to Improve the Purity of Plant Produced Recombinant Protein.

Plants are a newly developing eukaryotic expression system being explored to produce therapeutic proteins. Purification of recombinant proteins from plants is one of the most critical steps in the production process. Typically, proteins were purified from total soluble proteins (TSP), and the presence of miscellaneous intracellular proteins and cytochromes poses challenges for subsequent protein purification steps. Moreover, most therapeutic proteins like antigens and antibodies are secreted to obtain proper glycosylation, and the presence of incompletely modified proteins leads to inconsistent antigen or antibody structures. This work introduces a more effective method to obtain highly purified recombinant proteins from the plant apoplastic space. The recombinant Green fluorescent protein (GFP) is engineered to be secreted into the apoplast of Nicotiana benthamiana and is then extracted using an infiltration-centrifugation method. The GFP-His from the extracted apoplast is then purified by nickel affinity chromatography. In contrast to the traditional methods from TSP, purification from the apoplast produces highly purified recombinant proteins. This represents an important technological improvement for plant production systems.

Temporal artery biopsy for suspected giant cell arteritis: A mini review.

Giant cell arteritis (GCA) is a granulomatous inflammation involving medium and large vessels that can lead to serious clinical manifestations associated with tissue ischemia. Temporal artery biopsy (TAB) is currently the gold standard method for the diagnosis of GCA, with a specificity of 100% and a sensitivity of 77%. However, the false-negative rate for TAB ranges from 9% to 61%. False negatives may be related to the timing of biopsy, the length of specimen, and the existence of "skip lesions." We reviewed the relevant evidence for methods to improve the sensitivity and reduce the false-negative rate for TAB. To reduce the false-negative rate for TAB, it is recommended to perform TAB within 1 week of starting corticosteroid therapy. Although there is currently no consensus, we suggest that the temporal artery is cut to a length of 20‒30 mm and to prepare serial pathological sections. It is necessary to attach great importance to patients suspected of having GCA, and complete TAB should be performed as soon as possible while starting corticosteroid therapy promptly. We also discuss the clinical value of non-invasive vascular imaging technologies, such as DUS, CTA, MRA, and 18F-FDG-PET/CT, as auxiliary methods for GCA diagnosis that could partially replace TAB.

Case Report: Multimode Imaging of Chronic Syphilitic Chorioretinitis.

SIGNIFICANCE: The clinical manifestations of ocular syphilis may mimic those of other diseases, which may result in a missed diagnosis and delayed treatment. PURPOSE: We describe multimodal imaging findings and treatment outcomes of a patient with chronic syphilitic chorioretinitis. CASE REPORT: A 40-year-old male patient complained of progressive decreased visual acuity of his left eye for more than 1 year. The best-corrected visual acuity was 20/20 in the right eye and 3/50 in the left eye. Relative afferent pupillary defect and 1+ vitreous cells were detected in the left eye. The authors performed fundus examination, fluorescence angiography, ultrawide-field fundus autofluorescence, structure optical coherence tomography, wide-field montage optical coherence tomography angiography, and visual field. Laboratory tests including a toluidine red unheated serum test (1:32) and the Treponema pallidum antibody (9.01S/CO) showed positive results. Chronic syphilitic chorioretinitis was diagnosed in both eyes. The patient was admitted for administration of intravenous penicillin G for 14 days, followed by intramuscular benzathine penicillin G weekly for three doses. Six months after treatment, the toluidine red unheated serum test ratio had decreased to 1:2 (positive). The best-corrected visual acuity was 20/20 in the right eye and 6/20 in the left eye. The reexamination results showed that the ocular structure and capillaris flow partially recovered. CONCLUSIONS: Chronic syphilitic chorioretinitis profoundly affects the structure of the retina and choroid; however, eyes may partially recover after an effective treatment. Ultrawide-field imaging technology has several advantages, such as broader imaging field and more details provided, in determining syphilis-induced ocular disorders.

Changes of Peripapillary Capillary Density in Patients with Vogt-Koyanagi-Harada Disease Evaluated by Optical Coherence Tomography Angiography.

Objective: To analyze the longitudinal changes in peripapillary capillary density in patients with acute VKH with or without optic disc swelling by optical coherence tomography angiography (OCTA). Methods: Retrospective case series. 44 patients (88 eyes) were enrolled and were divided into two groups according to presence/absence of optic disc swelling before treatment. Peripapillary capillary images were obtained by OCTA before and after 6 months of corticosteroid treatment and used to determine the radial peripapillary capillary (RPC), retinal plexus, and choriocapillaris vessel perfusion densities. Results: Optic disc swelling was present in 12 patients (24 eyes) and absent in 32 patients (64 eyes). The sex distribution, age, intraocular pressure, and best-corrected visual acuity before and after treatment were not significantly different between the two groups (all P > 0.05). Compared to those in nonoptic disc swelling group, the percentages of decreased vessel perfusion densities after treatment in the supranasal (RPC, 100.00% vs. 75.00%), infranasal (RPC, 100.00% vs. 56.25%), infratemporal (RPC, 66.67% vs. 37.50%), and infranasal quadrants (retinal plexus, 83.33% vs. 56.25%) were significantly more in optic disc swelling group. The choriocapillaris vessel perfusion density increased after treatment in both groups. Conclusions: Decreases in vessel perfusion densities of the RPC and retinal plexus after treatment in VKH patients with optic disc swelling were more common than in those without optic disc swelling. The choriocapillaris vessel perfusion density increased after treatment, regardless of the presence/absence of optic disc swelling.

Correlation between serum immunoglobulin levels and retinal structure in patients with newly diagnosed Vogt­Koyanagi­Harada disease.

Immunoglobulins serve immunomodulatory roles in numerous autoimmune diseases. The aim of the present study was to investigate the correlations between serum Ig levels and retinal structural parameters in patients with newly diagnosed acute Vogt­Koyanagi­Harada (VKH) disease. A total of 138 participants were enrolled and the foveal thickness (FT), serous retinal detachment (SRD), sensory retinal thickness, central FT (CFT), cube volume (V) and cube average thickness (AT) were assessed by optical coherence tomography. The patients were divided, according to the extent of SRD, into a high­detachment group (>500 µm) and a low­detachment group (≤500 µm). Rate­scattering turbidimetry was performed to measure the Ig levels. The high­detachment group comprised 51 (36.96%) patients. The proportion of males was significantly greater in the high­detachment group compared with the low­detachment group (58.82 vs. 40.23%; P<0.05) and best­corrected visual acuity was significantly worse in the high­detachment group compared with the low­detachment group (P<0.001). The IgE levels in the high­detachment group were significantly greater compared with the low­detachment group (P<0.05). FT, SRD, CFT, V and AT were significantly greater in the high­detachment group compared with the low­detachment group (P<0.001). The IgE levels were positively associated with SRD, CFT and AT (P<0.05). Multivariate binary logistic regression analysis demonstrated that male sex (B=2.447; P<0.05) and serum IgE levels (B=0.997, P<0.05) may be independent risk factors for severe SRD. The results of the present study demonstrated that males are more likely to develop severe SRD and that serum IgE levels were associated with the extent of detachment. These data suggested that IgE may be involved in the progression of VKH disease.

Elevated Serum Immunoglobulin E Levels are Associated with the Severity of Newly Diagnosed, Acute Vogt-Koyanagi-Harada Disease.

OBJECTIVE: To investigate the correlation between serum immunoglobulin E (IgE) levels and severity of Vogt-Koyanagi-Harada (VKH) disease. METHODS: The medical records of patients with VKH disease between 2015 and 2020 were reviewed. Serum immunoglobulins (IgA, IgE, IgG, and IgM), tumor necrosis factor α (TNFα) and C-reactive protein (CRP) were measured. Patients were divided into IgE-positive (IgE ≥ 100 IU/mL) and IgE-negative (IgE < 100 IU/mL) groups. The best-corrected visual acuity (BCVA) and macular morphologic characteristics including foveal thickness (FT), serous retinal detachment (SRD), sensory retinal thickness (SRT), central foveal thickness (CFT), cube volume (V), and cube average thickness (AT) were determined in patients in both groups. RESULTS: Of 128 patients included in the study, 35 (27.34%) patients were IgE-positive, BCVA (logMAR) was worse in the IgE-positive group. The mean CRP (P= .012) and TNFα (P≤ 0.001) levels were greater in the IgE-positive group than in the IgE-negative group. Regarding macular morphologic characteristics, FT (P= .010), SDR (P= .004), CFT (P= .008), V (P= .013), and AT (P= .006) were significantly greater in the IgE-positive group than in the IgE-negative group. CONCLUSIONS: Elevated serum IgE levels were associated with more severe macular changes in patients with VKH disease. These findings suggest that IgE may be involved in the progression of VKH disease.

Dinucleotides as simple models of the base stacking-unstacking component of DNA 'breathing' mechanisms.

Regulatory protein access to the DNA duplex 'interior' depends on local DNA 'breathing' fluctuations, and the most fundamental of these are thermally-driven base stacking-unstacking interactions. The smallest DNA unit that can undergo such transitions is the dinucleotide, whose structural and dynamic properties are dominated by stacking, while the ion condensation, cooperative stacking and inter-base hydrogen-bonding present in duplex DNA are not involved. We use dApdA to study stacking-unstacking at the dinucleotide level because the fluctuations observed are likely to resemble those of larger DNA molecules, but in the absence of constraints introduced by cooperativity are likely to be more pronounced, and thus more accessible to measurement. We study these fluctuations with a combination of Molecular Dynamics simulations on the microsecond timescale and Markov State Model analyses, and validate our results by calculations of circular dichroism (CD) spectra, with results that agree well with the experimental spectra. Our analyses show that the CD spectrum of dApdA is defined by two distinct chiral conformations that correspond, respectively, to a Watson-Crick form and a hybrid form with one base in a Hoogsteen configuration. We find also that ionic structure and water orientation around dApdA play important roles in controlling its breathing fluctuations.

Local DNA Base Conformations and Ligand Intercalation in DNA Constructs Containing Optical Probes.

Understanding local conformations of DNA at the level of individual nucleic acid bases and base pairs is important for elucidating molecular processes that depend on DNA sequence. Here, we apply linear absorption and circular dichroism measurements to the study of local DNA conformations, using the guanine base analog 6-methyl isoxanthopterin (6-MI) as a structural probe. We show that the spectroscopic properties of this probe can provide detailed information about the average local base and basepair conformations as a function of the surrounding DNA sequence. Based on these results we apply a simple theoretical model to calculate the circular dichroism spectra of 6-MI-substituted DNA constructs and show that our model can be used to extract information about how the local conformations of the 6-MI probe are influenced by the local base or basepair environment. We also use this probe to examine the pathway for the insertion (intercalation) of a tethered acridine ligand (9-amino-6-chloro methoxyacridine) into duplex DNA. We show that this model intercalator interacts with duplex DNA by a "displacement insertion intercalation" mechanism, whereby the acridine moiety is inserted into the DNA structure and displaces the base located opposite its attachment site. These findings suggest that site-specifically positioned base analog probes can be used to characterize the molecular and structural details of binding ligand effects on local base stacking and unstacking reactions in single- and double-stranded DNA and thus may help to define the molecular mechanisms of DNA-protein interactions that involve the site-specific intercalation of aromatic amino acid side chains into genomic DNA.

Effects of NADH Availability on 3-Phenyllactic Acid Production by Lactobacillus plantarum Expressing Formate Dehydrogenase.

It is well known that cofactors play a key role in the production of different compounds in bioconversion processes, while the high cost of cofactors limits their usage in industrial applications. In the present study, a NADH regeneration system was successfully developed in Lactobacillus plantarum by expressing the fdh gene coding for formate dehydrogenase (FDH) from Candida boidinii. Results indicated that the FDH was expressed with the highest activity of 0.82 U/mg of protein when cells entered early stationary phase. In addition, the expression of FDH increased the intracellular level of NADH and NADH/NAD+ ratio in L. plantarum, and therefore, enhanced the NADH-dependent production of 3-phenyllactic acid (PLA) in repeated and fed-batch bioconversions. In brief, the results demonstrate that the NADH regeneration by expressing FDH is a promising strategy for producing NADH-dependent microbial metabolites in L. plantarum.

Sequence-Dependent Conformational Heterogeneity and Proton-Transfer Reactivity of the Fluorescent Guanine Analogue 6-Methyl Isoxanthopterin (6-MI) in DNA.

The local conformations of individual nucleic acid bases in DNA are important components in processes fundamental to gene regulation. Fluorescent nucleic acid base analogues, which can be substituted for natural bases in DNA, can serve as useful spectroscopic probes of average local base conformation and conformational heterogeneity. Here we report excitation-emission peak shift (EES) measurements of the fluorescent guanine (G) analogue 6-methyl isoxanthoptherin (6-MI), both as a ribonucleotide monophosphate (NMP) in solution and as a site-specific substituent for G in various DNA constructs. Changes in the peak positions of the fluorescence spectra as a function of excitation energy indicate that distinct subpopulations of conformational states exist in these samples on time scales longer than the fluorescence lifetime. Our pH-dependent measurements of the 6-MI NMP in solution show that these states can be identified as protonated and deprotonated forms of the 6-MI fluorescent probe. We implement a simple two-state model, which includes four vibrationally coupled electronic levels to estimate the free energy change, the free energy of activation, and the equilibrium constant for the proton transfer reaction. These parameters vary in single-stranded and duplex DNA constructs, and also depend on the sequence context of flanking bases. Our results suggest that proton transfer in 6-MI-substituted DNA constructs is coupled to conformational heterogeneity of the probe base, and can be interpreted to suggest that Watson-Crick base pairing between 6-MI and its complementary cytosine in duplex DNA involves a "low-barrier-hydrogen-bond". These findings may be important in using the 6-MI probe to understand local base conformational fluctuations, which likely play a central role in protein-DNA and ligand-DNA interactions.

[Proliferation apoptotic influence of crocin on human bladder cancer T24 cell line].

OBJECTIVE: To investigate the proliferation, apoptosis and mechanisms on T24 cell of transitional cell carcinoma of bladder (TCCB) by crocin. METHOD: MTT assay was used to evaluate the proliferation of T24 cells. The changes of cell cycle and cell apoptotic percentage were measured by flow cytometry. T24 cells were inoculated into BALB/c nude mice to establish model of carcinoma of bladder. The mice were randomly divided into control group and experimental group. After treatment with 50 mmol x L(-1) crocin, the inhibited growth of tumor was observed. Electronic microscope was used to observe the morphological changes. The expressions of Bcl-2, Bax, Survivin and Cyclin D1 were detected by immunohistochemistry. RESULT: The growth of T24 cells was remarkably inhibited after treatment of crocin. Flow cytometric profiles revealed that crocin led to the increase of the cells in G0/G1 phase, the percentage of cell apoptosis was also increased. Crocin could inhibit the growth of BALB/c xenograft tumor. The morphology changes of cell apoptosis were observed. Bcl-2, Cyclin D1 and survivin expressions determined by immunohistochemical staining were down-regulated after treatment with Bax expression up-regulated. CONCLUSION: Crocin exerts both in vitro and in vivo anti-cancer effect on TCCB T24 cell line. The mechanisms may change tumour cell cycle and induce tumour cell apoptosis by down-regulating the expression of Bcl-2, Survivin, Cyclin D1 and up-regulating the expression of Bax.

[Influence of crocin on gene expression profile of human bladder cancer cell lines T24].

OBJECTIVE: To investigate the changes of gene expression profile in transitional cell carcinoma of bladder T24 cell after crocin treatment, in order to find the possible crocin targets. METHOD: The bladder cancer T24 cell line was treated with crocin. MTT assay was adopted to determine the inhibition rate for selecting the best effect time and concentration of crocin. Differentially expressed genes on groups with or without treatment of crocin were screened with high throughout cDNA microarray. One up-regulated gene p21(WAF1) and one down-regulated gene cyclinD1 were selected to undergo analysis by the reverse transcription polymerase chain reaction (RT-PCR). Moreover, immunocytochemical method was used to evaluate p21(WAF1) and cyclinD1 protein expression. RESULT: The growth of T24 cells was inhibited remarkably following a marked positive correlation between crocin concentration, time and inhibitor rate. When 3 mmol x L(-1) crocin treated T24 cells for 48h, the difference was significant compared with the control group (P < 0.05). Crocin induced wide changes of the gene expression profile of T24 cells. A total of 836 genes were up-regulated or down-regulated by more than 2 times, which were involved cell cycle controlling, DNA cell apoptosis, replication factor, and so on. The mRNA expression of p21(WAF1) and cyclinD1 detected by RT-PCR were in accordance with cDNA microarray data. The results of immunocytochemical method showed that p21(WAF1) and cyclinD1 protein expression were consistent with those mRNA expression. CONCLUSION: Crocin can induce the significant alteration of gene expression profile of T24 cell. It is suggested that the widly konwn anti-tumor effects of crocin are medicated at least in part by regulating the cell cycle controlling gene expression.