Case report: A toxoplasmic encephalitis in an immunocompromised child detected through metagenomic next-generation sequencing.

There exist numerous pathogens that are capable of causing infections within the central nervous system (CNS); however, conventional detection and analysis methods prove to be challenging. Clinical diagnosis of CNS infections often depends on clinical characteristics, cerebrospinal fluid (CSF) analysis, imaging, and molecular detection assays. Unfortunately, these methods can be both insensitive and time consuming, which can lead to missed diagnoses and catastrophic outcomes, especially in the case of infrequent diseases. Despite the application of appropriate prophylactic regimens and evidence-based antimicrobial agents, CNS infections continue to result in significant morbidity and mortality in hospital settings. Metagenomic next-generation sequencing (mNGS) is a novel tool that enables the identification of thousands of pathogens in a target-independent manner in a single run. The role of this innovative detection method in clinical pathogen diagnostics has matured over time. In this particular research, clinicians employed mNGS to investigate a suspected CNS infection in a child with leukemia, and unexpectedly detected Toxoplasma gondii. Case: A 3-year-old child diagnosed with T-cell lymphoblastic lymphoma was admitted to our hospital due to a 2-day history of fever and headache, along with 1 day of altered consciousness. Upon admission, the patient's Glasgow Coma Scale score was 14. Brain magnetic resonance imaging revealed multiple abnormal signals. Due to the patient's atypical clinical symptoms and laboratory test results, determining the etiology and treatment plan was difficulty.Subsequently, the patient underwent next-generation sequencing examination of cerebrospinal fluid. The following day, the results indicated the presence of Toxoplasma gondii. The patient received treatment with a combination of sulfamethoxazole (SMZ) and azithromycin. After approximately 7 days, the patient's symptoms significantly improved, and they were discharged from the hospital with oral medication to continue at home. A follow-up polymerase chain reaction (PCR) testing after about 6 weeks revealed the absence of Toxoplasma. Conclusion: This case highlights the potential of mNGS as an effective method for detecting toxoplasmic encephalitis (TE). Since mNGS can identify thousands of pathogens in a single run, it may be a promising detection method for investigating the causative pathogens of central nervous system infections with atypical features.

The diagnostic value of next-generation sequencing technology in sepsis.

Objective: This study aims to assess the clinical utility of next-generation sequencing (NGS) in sepsis diagnosis. Methods: A prospective study was conducted on patients with a high suspicion of sepsis by unknown pathogens from January 2017 to December 2021. Blood samples were taken from patients to perform NGS, blood culture (BC), leucocyte (WBC), procalcitonin (PCT), creatinine (CREA), Albumin (ALB) and C-reactive protein (CRP) tests. Results: The feedback time for BC was 3~5 days for bacteria and 5~7 days for fungi, while the turnover time for NGS was only 24 h. The clinical diagnosis was considered the "gold standard". 83 patients passed our inclusion criteria and were separated into two groups by clinical diagnosis. 62 met the clinical diagnosis criteria for sepsis and 21 were non-sepsis. The data from the two groups were retrospectively compared and analyzed. Of 62 sepsis in 83 patients, 8(9.64%) were diagnosed by both BC and NGS, 51 (61.45%) by NGS only, 1(1.20%) by BC and 2 (2.41%) by conventional testing only; PCT, CREA, CRP levels and the detection rate of NGS and BC were higher in the sepsis group than in the non-sepsis group, while ALB levels were lower (p<0.05). The logistic regression results in our study revealed that NGS and ALB were independent prediction factors for sepsis (p<0.05), the area under the receiver operating characteristic curve (AUC), sensitivity and specificity of NGS for diagnosing sepsis was 0.857, 95.16% and 76.19%, while ALB was 0.728, 58.06%, 80.95%, respectively. The combination's sensitivity, specificity and AUC of NGS and ALB were 93.55%, 85.71% and 0.935, greater than that of Albumin or NGS only (both p<0.05). Conclusion: NGS can effectively and quickly identify pathogens, thereby emerges as a promising technology for sepsis diagnosis. Combination of NGS and ALB can be used for early screening and is more powerful than NGS or ALB only.

Case Report: A Candida Meningitis in an Immunocompetent Patient Detected Through the Next-Generation Sequencing.

Background: Fungal infections of the central nervous system (CNS) are not commonly seen clinically. Clinical diagnosis of fungal infections often depend on the pathogen culture and the clinical features. This method is time-consuming and insensitive, which can lead to misdiagnosis. The authors introduce an adult patient with fungal infections diagnosed by next-generation sequencing (NGS). Case: The patient was a 60-year-old male Chinese who had both hypermyotonia of the lower extremities and fever. The auxiliary examinations such as MRI, CT, and cerebrospinal fluid (CSF) analysis showed obvious abnormalities. Because of the difficulties in diagnosis, it was hard to determine the treatment plan. The NGS detected specific sequences of Candida albicans in 3 days. The patient was then treated with liposomal amphotericin B and fluconazole. About 3 weeks later, the symptoms of the patient improved significantly and he was discharged from the hospital. Conclusion: Compared with the routine cultural method, NGS has made a huge advancement in infection diagnosis and targeting antimicrobial therapy for CNS infection.

Correlation between contrast sensitivity and the lens opacities classification system III in age-related nuclear and cortical cataracts.

BACKGROUND: Contrast sensitivity (CS) testing can detect differences in functional vision and is highly correlated with visual performance. This study was designed to investigate the association between CS and the grading score using the lens opacities classification system (LOCS) III as well as the association between CS and visual acuity (VA) in nuclear or cortical age-related cataract (ARC) patients. METHODS: A total of 270 eyes with ARC and 30 control eyes were divided into nuclear opacity (NO), nuclear color (NC), cortical cataract (C) based on LOCS III. The CS values measured at all spatial frequencies under photopic and glare conditions that resulted in contrast sensitivity function (CSF) were evaluated, and LogMAR VA was tested with the Early Treatment Diabetic Retinopathy Study (ETDRS) chart. The correlation between CSF and LOCS III grading scores, and between CSF and LogMAR VA were analyzed. RESULTS: Compared to the controls, CSF of the nuclear or cortical ARC significantly declined. There are significant correlation between CSF and LogMAR VA, and between CSF and LOCS III grading scores. Compared to the VA, a stronger correlation existed between CSF and LOCS III grading score than that of LogMAR VA and LOCS III grading score. CS at some spatial frequencies is significantly influenced with LOCS III grading score. CONCLUSIONS: CSF significantly declined with the increasing ARC grading scores. Comparing to VA, CSF reflected the severity of cataract more comprehensively. CS at low spatial frequency is significantly influenced by ARC. Therefore, CS is more precise than VA in assessing the visual function of ARC patients.

Generalized atmospheric turbulence MTF for wave propagating through non-Kolmogorov turbulence.

A generalized exponential spectrum model is derived, which considers finite turbulence inner and outer scales and has a general spectral power law value between the range 3 to 5 instead of standard power law value 11/3. Based on this generalized spectrum model, a new generalized long exposure turbulence modulation transfer function (MTF) is obtained for optical plane and spherical wave propagating through horizontal path in weak fluctuation turbulence. When the inner scale and outer scale are set to zero and infinite, respectively, the new generalized MTF is reduced to the classical generalized MTF derived from the non-Kolmogorov spectrum.

Morning glory syndrome associated with posterior lenticonus.

The clinical features of the morning glory syndrome (MSG) are demonstrated in a 12-year-old male patient with the posterior lenticonus in the left eye. This patient had retinal detachment in the left eye. A complete ocular examination was performed and the patient underwent a pars plana vitrectomy of the left eye. Slit-lamp examination revealed the posterior lenticonus with the posterior subcapsular opacities in the left eye. The fundus showed the symptoms of MGS. The discs were pink and deeply excavated, surrounded by a ring of chorioretinal pigmentary disturbance. The retina has remained reattached for six months after surgery. Although most cases of MGS present with retinal and vitrea abnormalities, it may also occur in association with the lens anomalies, including the posterior lenticonus and subcapsular cataract. This association may be helpful to explore the pathogenesis of MGS.

[Screening of cataract surgery in four rural populations aged 50 years old and above in western China].

OBJECTIVE: To estimate the cataract surgical coverage and cataract surgery rate and to assess the visual outcome of cataract surgery among individuals aged at or over 50 years old in four rural populations from four different areas of western China. METHODS: This cross-sectional study, performed during the period 2003 - 2005, used the method of cluster sampling and recruited 5562 persons aged 50 years old or above through household census. Standardized ocular examinations including visual acuity test, intraocular pressure measurement, slit-lamp and fundus examination were performed. The main outcome criteria were cataract surgical coverage, cataract surgery rate, complication rate and visual outcome after cataract surgery. RESULTS: Of individuals with bilateral presenting visual acuity < 6/60 due to age-related cataract, the cataract surgical coverage was 54% in Qinghai. It was the highest among these four populations. The highest cataract surgery rate (CSR) value was 1551 in Qinghai and the lowest 143 in Guangxi during the period of 2000-2002. The overall intraocular lens implantation rate was 51.5% in 200 eyes with cataract surgery and 40.5% eyes with post-operative visual acuity < 6/60. The overall post-operative complication rate was 28%. CONCLUSION: In the beginning of 21st century, the cataract surgical coverage in four rural populations aged 50 years old or above in western China was low and similar to the situation of the last decade in eastern China. Cataract surgical technique and low IOL implantation rate are the main causes for a poor visual outcome. To reduce the risks of cataract blindness, the clinicians should substantially improve the visual outcome as well as the number of cataract surgery.

[Prevalence of age-related cataract among adults aged 50 and above in four rural areas in western China].

OBJECTIVE: To assess and compare the prevalence of age-related cataract (ARC) among adults aged 50 years or older in Western China. METHODS: Questionnaire survey and ophthalmologic examination were conducted among 5562 permanent rural residents aged 50 years and above in Ping' an County, Qinghai Province, Chuxiong City, Yunnan Province, Liupanshui City, Guizhou Province, and Chongzuo City, Guangxi Zhuang Autonomous region, selected by cluster sampling. All lenses were graded and classified for lens opacities by slit lamp, using the Lens Opacification Classification System (LOCS) II and standard photographs. Definite ARC was defined as either LOGS II nuclear opalescence of grade 1.0 or more and/or cortical cataract of grade 1.0 or more and/or posterior subcapsular cataract of grade 1.0 or more in persons with the visual acuity worse than 10/16. RESULTS: The overall response rate was 88.4%. The prevalence rates of ARC in one or both eyes was 41.8% in Qinghai, 48.2% in Yunnan, 18.8% in Guizhou and 39.4% in Guangxi. After age correction under the data of China Census 2000, the age-adjusted prevalence of ARC correspondingly changed to 44.1% in Qinghai, 45.9% in Yunnan, 18.8% in Guizhou, and 32.8% in Guangxi. The prevalence of ARC increased significantly with increasing age. In those eyes with ARC, cortical cataract was more common in Qinghai and Guizhou, while nuclear cataract was more common in Yunnan and Guangxi. The proportion of grades 4 lens opacities in Qinghai was 17.49%, higher than those in Yunnan, Guizhou, and Guangri (15.58%, 11.03%, and 10.00%. respectively). CONCLUSIONS: Generally the ARC prevalence among the permanent rural residents aged 50 and above in Western China is higher than that in Eastern China. And there is difference in the prevalence rate among different areas. Special attention should be paid toward this situation.

Quercetin inhibits choroidal and retinal angiogenesis in vitro.

BACKGROUND: Quercetin is a natural substance found abundantly in grapes, red wine and other food products. In this study, we examined the effect of quercetin on choroidal and retinal angiogenesis in vitro using rhesus choroids-retina endothelial cell line (RF/6A). METHODS: RF/6A cells were cultured in Dulbecco's Modified Eagle's Medium (DMEM) containing 10% fetal bovine serum. Then cells were treated with different concentrations (from 0 to 100 microM) of quercetin. The cell proliferation was assessed using choromogenic methylthiazol tetrazolium bromide (MTT) dye after 24, 48 and 72 hours. Cell migration after 24-hour incubation with quercetin was investigated by wound assay. Following exposure to the various concentrations of quercetin for 24 hours, tube formation on matrigel by endothelial cells was also analyzed. Apoptosis was measured by flow cytometry using annexin V-FITC and propidium iodide staining. RESULTS: Quercetin inhibits endothelial cell proliferation in a dose-dependent fashion; 10.1%, 42.6% and 65.2% inhibition on treating with 10, 50 and 100 microM Quercetin respectively. The migration and tube formation of RA/6A cells were also significantly inhibited by quercetin in a dose-dependent manner. Flow cytometric analysis showed that the percentages of apoptotic cells were slightly increased only in 100 microM quercetin-treated cells. CONCLUSIONS: Our results show that quercetin inhibits choroidal and retinal angiogenesis in vitro. Further studies are ongoing to evaluate this drug as a potential candidate for the treatment of choroidal or retinal neovascularization.

Responses of human lens epithelial cells to quercetin and DMSO.

PURPOSE: Oxidative stress is an initiating factor in the development of maturity-onset cataract. Diet has a significant impact on cataract development, and individual dietary components responsible for the protective effect include flavonoids, of which quercetin is the most important. The purpose of this study was to investigate the protective effect of quercetin and its toxicity for human lens epithelial cells (HLECs). METHODS: HLECs in culture were incubated for 48 hours with either 1% (vol/vol) dimethyl sulfoxide (DMSO) alone or with this concentration of DMSO and between 0.1 and 100 microM of quercetin. Nonstimulated cells served as control cultures. The viability of HLECs was measured by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) colorimetric assay. Gene expression was assessed with reverse transcription-polymerase chain reaction (RT-PCR). Cellular apoptosis was examined by in situ immunocytochemistry using terminal deoxynucleotidyl transferase-mediated biotin-dUTP nicked labeling (TUNEL) and by flow cytometry, using annexin V-FITC apoptosis detection. RESULTS: DMSO (1% vol/vol) decreased cell viability, increased cellular apoptosis, and upregulated Bax in these cells; 0.1 microM quercetin inhibited these effects and protected HLECs from the toxicity of DMSO. Higher concentrations of quercetin the viability of HLECs decreased. In a dose-dependent response to quercetin, cellular apoptosis increased and the change correlated with upregulation of Bax and decreased cell viability. CONCLUSIONS: Quercetin, at a low concentration (0.1 microM), protects HLECs and reverses the toxic effects of DMSO (1% vol/vol). However, at higher concentrations, quercetin is toxic to HLECs with an LD(50) of 90.85 microM. Quercetin induced apoptosis and upregulates apoptotic genes in HLECs in a dose-dependent manner.