Atypical hemolytic uremic syndrome and eculizumab therapy in children

Hemolytic uremic syndrome (HUS) is often encountered in children with acute kidney injury. Besides the well-known shiga toxin-producing Escherichia coli-associated HUS, atypical HUS (aHUS) caused by genetic complement dysregulation has been studied recently. aHUS is a rare, chronic, and devastating disorder that progressively damages systemic organs, resulting in stroke, end-stage renal disease, and death. The traditional treatment for aHUS is mainly plasmapheresis or plasma infusion; however, many children with aHUS will progress to chronic kidney disease despite plasma therapy. Eculizumab is a newly developed biologic that blocks the terminal complement pathway and has been successfully used in the treatment of aHUS. Currently, several guidelines for aHUS, including the Korean guideline, recommend eculizumab as the first-line therapy in children with aHUS. Moreover, life-long eculizumab therapy is generally recommended. Further studies on discontinuation of eculizumab are needed

Arrayed CRISPR screen with image-based assay reliably uncovers host genes required for coxsackievirus infection

Pooled CRISPR screens based on lentiviral systems have been widely applied to identify the effect of gene knockout on cellular phenotype. Although many screens were successful, they also have the limitation that genes conferring mild phenotypes or those essential for growth can be overlooked, as every genetic perturbation is incorporated in the same population. Arrayed screens, on the other hand, incorporate a single genetic perturbation in each well and could overcome these limitations. However, arrayed screens based on siRNA-mediated knockdown were recently criticized for low reproducibility caused by incomplete inhibition of gene expression. To overcome these limitations, we developed a novel arrayed CRISPR screen based on a plasmid library expressing a single guide RNA (sgRNA) and disrupted 1514 genes, encoding kinases, proteins related to endocytosis, and Golgi-localized proteins, individually using 4542 sgRNAs (three sgRNAs per gene). This screen revealed host factors required for infection by coxsackievirus B3 (CVB3) from Picornaviridae, which includes human pathogens causing diverse diseases. Many host factors that had been overlooked in a conventional pooled screen were identified for CVB3 infection, including entry-related factors, translational initiation factors, and several replication factors with different functions, demonstrating the advantage of the arrayed screen. This screen was quite reliable and reproducible, as most genes identified in the primary screen were confirmed in secondary screens. Moreover, ACBD3, whose phenotype was not affected by siRNA-mediated knockdown, was reliably identified. We propose that arrayed CRISPR screens based on sgRNA plasmid libraries are powerful tools for arrayed genetic screening and applicable to larger-scale screens.

Arrayed CRISPR screen with image-based assay reliably uncovers host genes required for coxsackievirus infection

Pooled CRISPR screens based on lentiviral systems have been widely applied to identify the effect of gene knockout on cellular phenotype. Although many screens were successful, they also have the limitation that genes conferring mild phenotypes or those essential for growth can be overlooked, as every genetic perturbation is incorporated in the same population. Arrayed screens, on the other hand, incorporate a single genetic perturbation in each well and could overcome these limitations. However, arrayed screens based on siRNA-mediated knockdown were recently criticized for low reproducibility caused by incomplete inhibition of gene expression. To overcome these limitations, we developed a novel arrayed CRISPR screen based on a plasmid library expressing a single guide RNA (sgRNA) and disrupted 1514 genes, encoding kinases, proteins related to endocytosis, and Golgi-localized proteins, individually using 4542 sgRNAs (three sgRNAs per gene). This screen revealed host factors required for infection by coxsackievirus B3 (CVB3) from Picornaviridae, which includes human pathogens causing diverse diseases. Many host factors that had been overlooked in a conventional pooled screen were identified for CVB3 infection, including entry-related factors, translational initiation factors, and several replication factors with different functions, demonstrating the advantage of the arrayed screen. This screen was quite reliable and reproducible, as most genes identified in the primary screen were confirmed in secondary screens. Moreover, ACBD3, whose phenotype was not affected by siRNA-mediated knockdown, was reliably identified. We propose that arrayed CRISPR screens based on sgRNA plasmid libraries are powerful tools for arrayed genetic screening and applicable to larger-scale screens.

A case of Creutzfeldt–Jakob disease in a patient on hemodialysis

abstractWe report an unusual case of probable Creutzfeldt–Jakob disease (CJD) in hemodialysis patient. A woman 59 years of age with a past history of hypertension and end-stage renal disease presented with a stuporous state preceded by rapidly progressive cognitive dysfunction, myoclonus, and akinetic mutism. At first, the cause of the altered mental status was assumed to be uremic or hypertensive encephalopathy combined with fever. Proper managements, however, did not improve the neurologic symptoms. Diffusion-weighted magnetic resonance imaging revealed bilaterally asymmetric high signal intensity in both basal ganglia and cerebral cortices. Electroencephalography showed diffuse generalized theta-to-delta range slow wave and intermittent medium-to-high voltage complexes with a characteristic triphasic pattern on both hemispheres. Cerebrospinal fluid assay for the 14-3-3 protein was positive and diagnostic of CJD

Clinical features and outcomes of elderly patients with antineutrophil cytoplasmic antibody-positive vasculitis: a single-center retrospective study

Background We aimed to investigate the clinical characteristics and outcomes of patients aged ≥65 years with antineutrophil cytoplasmic autoantibody (ANCA)-positive ANCA-associated vasculitis (AAV) in Korea. Methods Seventy patients diagnosed with ANCA-positive AAV from 2006 to 2019 at a single center were analyzed and categorized into younger (aged <65 years) or elderly (aged ≥65 years) groups. Initial induction treatments were investigated according to age group. All-cause mortality and kidney outcomes were evaluated. Results After categorization by age, 34 (48.6%) and 36 patients (51.4%) were in the younger and elderly groups, respectively. In the elderly group, more patients were treated with oral cyclophosphamide (CYC) (30.6%) than with intravenous CYC (19.4%). During a median follow-up of 14.6 months (range, 3.0–53.1 months), 13 patients died (elderly group: 11 patients, 84.6%). In the elderly group, older age (hazard ratio [HR], 1.44; 95% confidence interval [CI], 1.09–1.90; p = 0.01), lower hemoglobin (HR, 0.21; 95% CI, 0.08–0.60; p = 0.003), and higher serum creatinine level (HR 14.17; 95% CI, 1.29–155.84; p = 0.03) were significant risk factors for all-cause mortality after adjustment. Oral CYC + steroid treatment was associated with decreased all-cause mortality compared to untreated induction immunosuppressants (HR, 0.01; 95% CI, 0.001–0.47; p = 0.02). Kidney failure or kidney recovery outcomes were not significantly different between the younger and elderly groups. Conclusion Patients aged ≥65 years had higher mortality rates than younger patients, and mortality was associated with older age, lower hemoglobin, higher serum creatinine level, and nontreatment compared to oral CYC + steroids

Clinical features of children with carbon monoxide intoxication: a single center study

Purpose To investigate the effect of lifestyle changes on patterns of carbon monoxide (CO) exposure and the association between neurologic symptoms and outcomes in Korean children with CO intoxication. Methods We reviewed the medical records of patients (< 18 years) with CO intoxication who visited the emergency department of Pusan National University Hospital between February 2012 and January 2020. We collected clinical findings, including age and sex, transfer from other hospitals, source, time and duration of exposure, manifestations with neurologic symptoms (syncope, seizure, and altered mental status), intensive care unit hospitalization, hospital length of stay, implementation of hyperbaric oxygen therapy, and findings of neuroimaging. These variables were compared between children with and without neurologic symptoms. In addition, levels of carboxyhemoglobin and lactate were compared between patients with and without specific manifestations. Results The enrolled 47 patients’ median age was 10 years (interquartile range, 4.5-14.0). The most common source of exposure was fire (46.8%), followed by camping (23.4%). The most common times of exposure were night (44.7%) and winter (44.7%). The patients with neurologic symptoms (14 [29.8%]) showed longer duration of exposure and hospital length of stay (P < 0.001 and P = 0.007, respectively). Of the 14 patients, 2 were hospitalized to the intensive care unit without an in-hospital mortality. A significant association was found between dyspnea and lactate level (P = 0.049), also between syncope or presyncope and carboxy hemoglobin level (P = 0.017). Conclusion CO intoxication in Korean children is most often caused by fire and camping, and at night and in winter. There is a correlation between neurologic symptoms and duration of exposure to CO

Effects of 12 weeks nutrition education on nutritional status in hemodialysis patients

Protein-energy malnutrition is present in a large proportion of patients with end stage renal disease and, is a strong risk factor for mortality in these patients. This study was aimed to evaluate the effectiveness of 12-weeks nutrition education during the hemodialysis session for the improvement of nutritional status. From the June 2011 to the September 2011, patients who were on regular hemodialysis in Pusan National University Hospital were enrolled in this study. In education group, intensive nutrition education was performed by the hemodialysis nurse, for fifty to sixty minutes during the hemodialysis session, once a week. Curriculum for renal nutrition includes regular taking of their medication, intake of moderate amount of protein and sufficient calories, reduction of water, salt, potassium and phosphate intake. Otherwise, any education program was not performed in patients of control group. Nutrition status was assessed by the subjective global assessment (SGA),body mass index (BMI), triceps skinfold thickness (TSF), arm muscle area(AMC) and laboratory markers such as serum albumin, serum blood urea nitrogen(BUN) and hemoglobin(Hb) level before and after the education. Effect of nutrition education was analyzed using ANCOVA test. A total of 49 patients were enrolled in this study and nutrition education was provided to 25 hemodialysis patients. Their mean age was 57.20±15.49 in education group and 55.13±14.42 in control groupand male was 56.0% in education group and 50.0% in control group and, other baseline characteristics were not significantly different between two groups. After the 12-week education, significant improvement was found in SGA, serum albumin, BUN and Hb level. SGA score was improved from 6.36±0.99 to 6.72±0.61 in education group, compared to control group(6.38±0.88 to 6.42±0.88, p=0.029 ). Improvement of serum albumin level, BUN and Hb was as follows: serum albumin(4.23±0.28 to 4.30±0.25 in education group, 4.28±0.39 to 4.13±0.34 in control group, p=0.040), serum Hb(10.45±1.49 to 11.13±1.74 in education group, 10.51±1.12 to 10.04±1.02 in control group, P=0.004), serum BUN(66.52±18.76 to 70.94±17.26 in education group, 59.50±13.61 to 58.68±13.88 in control group, p=0.032). 12 week nutrition education during the hemodialysis session by hemodialysis nurse was effectiv

A new classification system for bacterial Rieske non-heme iron aromatic ring-hydroxylating oxygenases

<p>Abstract</p> <p>Background</p> <p>Rieske non-heme iron aromatic ring-hydroxylating oxygenases (RHOs) are multi-component enzyme systems that are remarkably diverse in bacteria isolated from diverse habitats. Since the first classification in 1990, there has been a need to devise a new classification scheme for these enzymes because many RHOs have been discovered, which do not belong to any group in the previous classification. Here, we present a scheme for classification of RHOs reflecting new sequence information and interactions between RHO enzyme components.</p> <p>Result</p> <p>We have analyzed a total of 130 RHO enzymes in which 25 well-characterized RHO enzymes were used as standards to test our hypothesis for the proposed classification system. From the sequence analysis of electron transport chain (ETC) components of the standard RHOs, we extracted classification keys that reflect not only the phylogenetic affiliation within each component but also relationship among components. Oxygenase components of standard RHOs were phylogenetically classified into 10 groups with the classification keys derived from ETC components. This phylogenetic classification scheme was converted to a new systematic classification consisting of 5 distinct types. The new classification system was statistically examined to justify its stability. Type I represents two-component RHO systems that consist of an oxygenase and an FNR_C-type reductase. Type II contains other two-component RHO systems that consist of an oxygenase and an FNR_N-type reductase. Type III represents a group of three-component RHO systems that consist of an oxygenase, a [2Fe-2S]-type ferredoxin and an FNR_N-type reductase. Type IV represents another three-component systems that consist of oxygenase, [2Fe-2S]-type ferredoxin and GR-type reductase. Type V represents another different three-component systems that consist of an oxygenase, a [3Fe-4S]-type ferredoxin and a GR-type reductase.</p> <p>Conclusion</p> <p>The new classification system provides the following features. First, the new classification system analyzes RHO enzymes as a whole. RwithSecond, the new classification system is not static but responds dynamically to the growing pool of RHO enzymes. Third, our classification can be applied reliably to the classification of incomplete RHOs. Fourth, the classification has direct applicability to experimental work. Fifth, the system provides new insights into the evolution of RHO systems based on enzyme interaction.</p