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1.
J Clin Immunol ; 44(7): 149, 2024 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-38896305

RESUMO

Chronic granulomatous disease (CGD) primarily results from inherited defects in components of the nicotinamide adenine dinucleotide phosphate oxidase enzyme complex. These include gene defects in cytochrome B-245/558 subunit α/ß and neutrophil cytosolic factors 1, 2, and 4. Recently, homozygous loss-of-function variants in cytochrome B-245 chaperone 1 gene (CYBC1) have been discovered to cause CGD (CYBC1-CGD). Data on variant-proven CGD from low-income countries, the most underprivileged regions of the world, remain sparse due to numerous constraints. Herein, we report the first cohort of patients with CGD from Nepal, a low-income country in the Himalayas' challenging terrain. Our report includes a description of a new case of CYBC1 deficiency who was first diagnosed with CGD at our center. Only a dozen cases of CYBC1-CGD have been described in the literature thus far which have been reviewed comprehensively herein. Most of these patients have had significant infections and autoimmune/inflammatory manifestations. Pulmonary and invasive/disseminated bacterial/fungal infections were the most common followed by skin and soft-tissue infections. Inflammatory bowel disease (IBD) was the most common inflammatory manifestation (median age at diagnosis: 9 years) followed by episodes of recurrent/prolonged fever. Other autoimmune/inflammatory manifestations reported in CYBC1-CGD include acute pancreatitis, hemophagocytic lymphohistiocytosis, systemic granulomatosis, interstitial lung disease, arthritis, autoimmune hemolytic anemia, uveitis, nephritis, and eczema. Our analysis shows that patients with CYBC1-CGD are at a significantly higher risk of IBD-like illness as compared to other forms of CGD which merits further confirmatory studies in the future.


Assuntos
Doença Granulomatosa Crônica , Humanos , Doença Granulomatosa Crônica/genética , Doença Granulomatosa Crônica/diagnóstico , Nepal/epidemiologia , Masculino , Feminino , Criança , NADPH Oxidases/genética , NADPH Oxidases/deficiência , Pré-Escolar , Adolescente , Mutação/genética
2.
Rheumatology (Oxford) ; 63(2): 392-398, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-37202349

RESUMO

OBJECTIVES: Kawasaki disease (KD) is a medium vessel vasculitis with a predilection to involve coronary arteries. However, there is a paucity of literature on microvascular changes in patients with KD. METHODS: Children diagnosed with KD based on American Heart Association guidelines 2017 were enrolled prospectively. Demographic details and echocardiographic changes in coronaries were recorded. Nailfold capillaries were assessed using Optilia Video capillaroscopy and data were analysed using Optilia Optiflix Capillaroscopy software at acute (prior to IVIG administration) and subacute/convalescent phase. RESULTS: We enrolled 32 children with KD (17 boys) with a median age of 3 years. Nailfold capillaroscopy (NFC) was performed in 32 patients in the acute phase (compared with 32 controls) and in 17 during the subacute/convalescent phase at a median follow-up of 15 (15-90) days after IVIG treatment. The following findings were seen in NFC in the acute phase of KD: reduced capillary density (n = 12, 38.6%), dilated capillaries (n = 3, 9.3%), ramifications (n = 3, 9.3%) and capillary haemorrhages (n = 2, 6.2%). Capillary density was reduced significantly in the acute phase of KD (38.6%) as compared with the subacute/convalescent phase (25.4%) (P-value <0.001) and controls (0%) (P-value = 0.03). We observed no correlation between coronary artery involvement and mean capillary density (P = 0.870). CONCLUSION: Results show that patients with KD have significant nailfold capillary changes in the acute phase. These findings may provide a new diagnostic paradigm for KD and a window to predict coronary artery abnormalities.


Assuntos
Angioscopia Microscópica , Síndrome de Linfonodos Mucocutâneos , Masculino , Criança , Humanos , Pré-Escolar , Angioscopia Microscópica/métodos , Síndrome de Linfonodos Mucocutâneos/diagnóstico por imagem , Imunoglobulinas Intravenosas/uso terapêutico , Unhas/diagnóstico por imagem , Unhas/irrigação sanguínea , Capilares/diagnóstico por imagem
3.
Int Arch Allergy Immunol ; 185(4): 370-381, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38194943

RESUMO

INTRODUCTION: X-linked lymphoproliferative syndrome (XLP) is a rare primary immune deficiency. Two types of XLP have been described: XLP-1 and XLP-2. METHODS: We found 7 patients with XLP (3 had XLP-1 and 4 had XLP-2) after reviewing the data from Pediatric Immunodeficiency Clinic from 1997 to 2021. RESULTS: Mean age at diagnosis was 3.8 years, and mean delay in diagnosis was 2.6 years. Five patients had recurrent episodes of infections. Four patients developed at least one episode of hemophagocytic lymphohistiocytosis (HLH) (2 with XLP-1 and 2 with XLP-2). Of these, 2 had recurrent HLH (both with XLP-2). Epstein-Barr virus (EBV) infection was detected in 2 (1 with XLP-1 and 1 with XLP-2). Both these patients had HLH. One child with XLP-2 had inflammatory bowel disease. Hypogammaglobulinemia was seen in 3 (2 with XLP-1 and 1 with XLP-2). Genetic analysis showed previously reported variants in 5, while 2 had novel variants (one in exon 7 of XIAP gene [c.1370dup p.Asn457Lysfs Ter16] and other had splice site variant in intron 1 of SH2D1A gene [c.138-2_138-1insG]). Episodes of HLH were managed with intravenous immunoglobulin (IVIg), methylprednisolone, oral prednisolone, cyclosporine, and rituximab. Inflammatory bowel disease was managed using oral prednisolone and azathioprine. One patient underwent haploidentical hematopoietic stem cell transplantation. One child with XLP-2 and WAS died because of fulminant pneumonia. DISCUSSION/CONCLUSIONS: XLP should be considered as a strong possibility in any patient with features of HLH, repeated infections with hypogammaglobulinemia, persistent EBV infection, and early-onset IBD.


Assuntos
Agamaglobulinemia , Infecções por Vírus Epstein-Barr , Doenças Inflamatórias Intestinais , Linfo-Histiocitose Hemofagocítica , Transtornos Linfoproliferativos , Criança , Humanos , Agamaglobulinemia/diagnóstico , Agamaglobulinemia/genética , Agamaglobulinemia/terapia , Infecções por Vírus Epstein-Barr/diagnóstico , Infecções por Vírus Epstein-Barr/complicações , Herpesvirus Humano 4/genética , Transtornos Linfoproliferativos/diagnóstico , Transtornos Linfoproliferativos/genética , Transtornos Linfoproliferativos/terapia , Linfo-Histiocitose Hemofagocítica/diagnóstico , Linfo-Histiocitose Hemofagocítica/genética , Linfo-Histiocitose Hemofagocítica/terapia , Prednisolona
4.
J Clin Immunol ; 44(1): 17, 2023 12 22.
Artigo em Inglês | MEDLINE | ID: mdl-38129705

RESUMO

PURPOSE: Inherited deficiencies of CD40 and CD40 ligand (CD40L) reflect the crucial immunological functions of CD40-CD40L interaction/signaling. Although numerous studies have provided a detailed description of CD40L deficiency, reports of CD40 deficiency are scarce. Herein, we describe the characteristics of all reported patients with CD40 deficiency. METHODS: The PubMed, Embase and Web of Science databases were searched for relevant literature published till 7th August 2023. Study deduplication and identification of relevant reports was performed using the online PICO Portal. The data were extracted using a pre-designed data extraction form and the SPSS software was used for analysis. RESULTS: Systematic literature review revealed 40 unique patients with CD40 deficiency. Respiratory tract and gastrointestinal infections were the predominant clinical manifestations (observed in 93% and 57% patients, respectively). Sclerosing cholangitis has been reported in nearly one-third of patients. Cryptosporidium sp. (29%) and Pneumocystis jirovecii (21%) were the most common microbes identified. Very low to undetectable IgG levels and severely reduced/absent switch memory B cells were observed in all patients tested/reported. Elevated IgM levels were observed in 69% patients. Overall, splice-site and missense variants were the most common (36% and 32%, respectively) molecular defects identified. All patients were managed with immunoglobulin replacement therapy and antimicrobial prophylaxis was utilized in a subset. Hematopoietic stem cell transplantation (HSCT) has been performed in 45% patients (curative outcome observed in 73% of these patients). Overall, a fatal outcome was reported in 21% patients. CONCLUSIONS: We provide a comprehensive description of all important aspects of CD40 deficiency. HSCT is a promising curative treatment option for CD40 deficiency.


Assuntos
Criptosporidiose , Cryptosporidium , Síndrome de Imunodeficiência com Hiper-IgM , Síndromes de Imunodeficiência , Linfopenia , Humanos , Ligante de CD40/genética , Síndrome de Imunodeficiência com Hiper-IgM/genética , Síndromes de Imunodeficiência/genética , Antígenos CD40/genética , Imunoglobulina M
5.
Pediatr Nephrol ; 38(11): 3663-3670, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37335381

RESUMO

BACKGROUND: Enhanced availability of high-throughput sequencing (at progressively reducing costs) has revolutionized the identification of monogenic SRNS. However, in resource-poor settings, it may not be possible to perform next-generation sequencing (NGS) in all children wherein monogenic SRNS is suspected. Besides, the optimal strategy of genetic evaluation (in patients with SRNS) in routine clinical practice in resource-limited settings is unknown. METHODS: Patients with newly diagnosed SRNS were recruited from our center and followed up prospectively. We analyzed the factor(s) independently predicting the occurrence of disease-causing variants in these patients. RESULTS: In our study, 36 children/adolescents with SRNS were included (initial steroid resistance in 53%). On targeted NGS, pathogenic/likely pathogenic variants were identified in 31% (n = 11). These included homozygous or compound heterozygous variants in the following genes: ALOX12B, COL4A3, CRB2, NPHS1, NPHS2, PLCE1, and heterozygous variant in WT1 gene. Overall, 14 variants were identified of which 5 (36%) were novel. Age of < 1 or < 2 years and presence of family history of nephrotic syndrome independently predicted the occurrence of monogenic SRNS on multivariate analysis. CONCLUSIONS: While NGS-based genetic testing in SRNS is increasingly being incorporated in routine clinical practice the world over, the scenario is far from optimal in resource-limited settings. Our study highlights that resources for genetic testing in SRNS should be prioritized for patients with early age at disease onset and presence of family history. Larger studies composed of diverse multi-ethnic cohorts of patients with SRNS are required to further delineate the optimal strategy of genetic evaluation in resource-poor settings. A higher resolution version of the Graphical abstract is available as Supplementary information.


Assuntos
Síndrome Nefrótica , Adolescente , Criança , Humanos , Pré-Escolar , Síndrome Nefrótica/tratamento farmacológico , Síndrome Nefrótica/genética , Síndrome Nefrótica/diagnóstico , Proteínas de Membrana/genética , Testes Genéticos , Sequenciamento de Nucleotídeos em Larga Escala , Mutação , Análise Mutacional de DNA
6.
Rheumatol Int ; 43(1): 33-45, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36469106

RESUMO

We performed a systematic review and meta-analysis of studies evaluating vascular function in patients with JIA. Relevant literature published from 1st January 1965 to 1st March 2022 was searched systematically utilizing PubMed, Web of Science, and Embase databases. Observational studies were included-patients with JIA (classified according to the International League of Associations for Rheumatology criteria) were included as cases (study population) and age/sex-matched healthy participants as controls (comparator group). Outcome measures were differences in non-invasive parameters of vascular function. Online Population, Intervention, Comparison, Outcomes Portal was used for deduplication of studies and data extraction. Review Manager, Comprehensive Meta-analysis, and Meta-Essential softwares were used for data synthesis/analysis (encompassing data pooling and evaluation of heterogeneity and publication bias). Newcastle-Ottawa Scale and GRADEpro GDT software were utilized to assess study quality and certainty of evidence, respectively. Of 338 citations, 17 observational studies with 1423 participants (cases = 757, controls = 666) were included. Carotid intima-media thickness (CIMT) was higher [mean difference (MD) 0.02 mm {95% confidence interval (CI) 0.01-0.04}, p = 0.0006, I2 = 69%] in patients with JIA. Besides, decreased flow-mediated dilatation (FMD) [MD - 2.18% {95%CI - 3.69- - 0.68}, p = 0.004, I2 = 73%] was also observed. Results of studies assessing pulse wave velocity or arterial stiffness could not be pooled due to significant methodological variations. A 'very low' certainty of evidence suggests the presence of vascular dysfunction in JIA. Future longitudinal studies are required to determine whether altered CIMT and FMD in patients with JIA translate to an enhanced risk of (adverse) clinical cardiovascular events. PROSPERO (CRD42022323752).


Assuntos
Artrite Juvenil , Rigidez Vascular , Humanos , Espessura Intima-Media Carotídea , Artrite Juvenil/complicações , Artrite Juvenil/diagnóstico , Análise de Onda de Pulso , Endotélio Vascular
7.
Cardiol Young ; 33(9): 1614-1626, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36102118

RESUMO

BACKGROUND: Long-term physiological dysfunction in coronary/systemic vasculature may persist in individuals with Kawasaki disease even in the absence of coronary artery abnormalities. We perform a systematic review and meta-analyses of studies assessing long-term vascular function in Kawasaki disease. METHODS: PubMed, Embase, and Web of Science databases were searched for relevant literature published till May 2021. Patients with Kawasaki disease were included as cases and healthy age/sex-matched individuals as controls. Newcastle Ottawa Scale was used to assess the study quality. Outcome measures were differences in markers of vascular function 1 year after diagnosis of Kawasaki disease. Data were analysed using Review Manager software. Comprehensive meta-analysis software was used for meta-regression. To assess the certainty of evidence, GRADE Profiler software was utilised. RESULTS: Of 2280 citations, 49 case-control studies (comprising 2714 cases and 2118 controls) were included for data synthesis. Decreased flow-mediated dilatation [3.83, 95%CI 0.94-6.72] and increased pulse-wave velocity [39.34 cm/sec, 95%CI 20.86-57.83], arterial stiffness [0.35, 95%CI 0.11-0.59], and common carotid artery intima-media thickness were noted in patients with Kawasaki disease. No significant difference was observed for nitroglycerine-mediated dilatation and endothelial peripheral artery tonometry (endo-PAT). Significant inter-study heterogeneity was observed for flow-mediated dilatation, arterial stiffness, carotid artery intima-media thickness, and endo-PAT. The GRADE evidence was of 'very low quality' for all outcome measures except 'moderate quality' for pulse-wave velocity. CONCLUSIONS: Evidence suggests the presence of long-term endothelial dysfunction in patients with Kawasaki disease even in the absence of coronary artery abnormalities. Avoidance of development of other cardiovascular risk factors seems prudent in patients with Kawasaki disease.


Assuntos
Doença da Artéria Coronariana , Síndrome de Linfonodos Mucocutâneos , Rigidez Vascular , Humanos , Síndrome de Linfonodos Mucocutâneos/complicações , Espessura Intima-Media Carotídea , Doença da Artéria Coronariana/etiologia , Artéria Carótida Primitiva , Estudos de Casos e Controles , Dilatação Patológica , Rigidez Vascular/fisiologia , Análise de Onda de Pulso
8.
J Trop Pediatr ; 69(3)2023 04 05.
Artigo em Inglês | MEDLINE | ID: mdl-37608506

RESUMO

Various factors (e.g., infections) have been postulated to trigger Kawasaki disease (KD) in genetically predisposed individuals. Whether neoplasms can trigger KD is largely unknown due to paucity of data. Herein, we provide a detailed account of KD occurring in temporal proximity (within 6 months) to neoplasms ('neoplasm-KD'). Patients with 'neoplasm-KD' diagnosed/treated at our center from January 1994 to May 2021 were included. Additionally, we performed a systematic literature review (as per PRISMA 2020 guidelines) utilizing PubMed, Web of Science and Scopus databases to retrieve details of all patients with 'neoplasm-KD' reported till June 2021. Patients with multisystem inflammatory syndrome in children were excluded. As all reports pertained to case description(s), risk of bias assessment was not performed. The details of patients with 'neoplasm-KD' were analyzed using SPSS software. Primary and secondary outcomes were occurrence of coronary artery abnormalities (CAAs) and clinical characteristics of 'neoplasm-KD', respectively. A total of 25 patients (data from 18 reports) were included in the 'neoplasm-KD' dataset. The most frequently diagnosed neoplasm was acute lymphoblastic leukemia followed by neuroblastoma and acute myeloblastic leukemia. Overall, CAAs were noted in 48% of patients. Interval between diagnoses of KD and neoplasm was shorter in patients with CAAs as compared to patients with normal coronary arteries (p-value = 0.03). Besides providing a comprehensive description of 'neoplasm-KD', this study raises a possibility that neoplasms might trigger KD. Also, 'neoplasm-KD' may be associated with a higher risk of development of CAAs. However, the small size of 'neoplasm-KD' dataset precludes definitive conclusions regarding this association. Funding: nil. Registration: PROSPERO (CRD42021270458).


This study is the first exhaustive description of cancers and Kawasaki disease (KD) occurring in close temporal proximity. Nearly half of these patients develop coronary artery abnormalities. In KD, persistent lymphadenopathy, enlargement of liver/spleen and development of low blood cell counts should trigger evaluation for cancer. Our study also raises a possibility that cancers might occasionally trigger KD.


Assuntos
Síndrome de Linfonodos Mucocutâneos , Neoplasias , Criança , Humanos , Predisposição Genética para Doença , Síndrome de Linfonodos Mucocutâneos/complicações , Síndrome de Linfonodos Mucocutâneos/epidemiologia , Neoplasias/epidemiologia , Neoplasias/etiologia
9.
J Clin Immunol ; 42(7): 1434-1450, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35726044

RESUMO

PURPOSE: Specific granule deficiency (SGD) is a rare inborn error of immunity resulting from loss-of-function variants in CEBPE gene (encoding for transcription factor C/EBPε). Although this genetic etiology has been known for over two decades, only a few patients with CEBPE variant-proven SGD (type I) have been reported. Herein, we describe two siblings with a novel homozygous CEBPE deletion who were noted to have profound neutropenia on initial evaluation. We aimed to evaluate the immunohematological consequences of this novel variant, including profound neutropenia. METHODS: Light scatter characteristics of granulocytes were examined on various automated hematology analyzers. Phagocyte immunophenotype, reactive oxygen species generation, and Toll-like receptor (TLR) signaling were assessed using flow cytometry. Relative expression of genes encoding various granule proteins was studied using RT-PCR. Western blot analysis and luciferase reporter assay were performed to explore variant C/EBPε expression and function. RESULTS: Severe infections occurred in both siblings. Analysis of granulocyte light scatter plots revealed automated hematology analyzers can provide anomalously low neutrophil counts due to abnormal neutrophil morphology. Neutrophils displayed absence/marked reduction of CD15/CD16 expression and overexpression (in a subset) of CD14/CD64. Three distinct populations of phagocytes with different oxidase activities were observed. Impaired shedding of CD62-ligand was noted on stimulation with TLR-4, TLR-2/6, and TLR-7/8 agonists. We demonstrated the variant C/EBPε to be functionally deficient. CONCLUSION: Homozygous c.655_665del variant in CEBPE causes SGD. Anomalous automated neutrophil counts may be reported in patients with SGD type I. Aberrant TLR signaling might be an additional pathogenetic mechanism underlying immunodeficiency in SGD type I.


Assuntos
Transtornos Leucocíticos , Neutropenia , Humanos , Proteínas Estimuladoras de Ligação a CCAAT/genética , Proteínas Estimuladoras de Ligação a CCAAT/metabolismo , Transtornos Leucocíticos/genética , Neutropenia/diagnóstico , Neutropenia/genética , Neutropenia/complicações , Neutrófilos
10.
Lupus ; 30(12): 2003-2007, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34652230

RESUMO

Systemic lupus erythematosus (SLE) is a complex multisystemic autoimmune disease. Lupus enteritis (LE), one of the less commonly described manifestations of childhood SLE, presents with relatively nonspecific clinical and laboratory features. In addition, recurrent episodes of LE occurring in temporal proximity are rare in children. Presence of disease activity at other sites (which may not be seen universally) supports the diagnosis of LE in an appropriate setting. Because of its potential role to cause ischemic complications, early recognition and prompt treatment are necessary for a good outcome. Herein, we describe a child with recurrent LE with an interval of about 3 months between the first and the second episode. The first episode correlated with systemic disease activity and bowel thickening was noted on abdominal ultrasonography. This episode was successfully managed with intravenous methylprednisolone pulse therapy. Conversely, the second episode was not associated with significant clinical and laboratory evidence of disease activity at other sites and the initial abdominal ultrasonography was non-contributory. Diagnostic and therapeutic delays, hence, led to the development of fatal complications. We highlight that a high index of suspicion of LE and a timely aggressive treatment is imperative for optimal outcomes even in rare pediatric cases of recurrent LE that may have normal imaging findings initially and may not be associated with systemic lupus erythematosus disease activity index (SLEDAI).


Assuntos
Enterite/epidemiologia , Perfuração Intestinal/etiologia , Lúpus Eritematoso Sistêmico , Criança , Enterite/diagnóstico , Enterite/tratamento farmacológico , Enterite/etiologia , Feminino , Humanos , Imunossupressores/uso terapêutico , Lúpus Eritematoso Discoide , Lúpus Eritematoso Sistêmico/complicações , Lúpus Eritematoso Sistêmico/diagnóstico , Lúpus Eritematoso Sistêmico/tratamento farmacológico , Ultrassonografia
11.
J Trop Pediatr ; 67(1)2021 01 29.
Artigo em Inglês | MEDLINE | ID: mdl-33280037

RESUMO

BACKGROUND: Childhood diffuse brainstem glioma (dBSG) is a rare tumor with a poor prognosis. Any tumor-directed surgical intervention is difficult. Magnetic resonance imaging forms the mainstay of diagnosis and radiation therapy has remained the backbone of therapy. In this study, we compare the outcomes of conformal radiotherapy with conventional therapy in the context of resource-constrained settings. METHODS: In this retrospective analysis, conducted between 2010 and 2019, all pediatric patients with a diagnosis of dBSG were analyzed. The survival data were calculated in months from the date of diagnosis. Survival differences between variables were compared using the Log-rank test and the risk of death was calculated using Cox regression analysis. RESULTS: A total of 20 patients (11 males, 55%) with a diagnosis of dBSG were included. Median age at diagnosis was 6.5 years. No surgical resection or biopsy was done in any patient. Fifteen (75%) patients received radiotherapy and only 4 (20%) patients received additional chemotherapy. Five (25%) patients did not receive any form of anti-cancer therapy. Median overall survival (OS) was 8 months (95% CI 5.2-10.8). Females were at a higher risk of death than males. Children treated with radiotherapy had a longer OS than untreated children; however, the modality of radiotherapy employed or the addition of chemotherapy did not affect the OS. CONCLUSION: Radiotherapy, irrespective of the modality, increases the survival of children with dBSG in resource-poor settings. Additionally, socioeconomic concerns need to be addressed in the management of these tumors, especially in the case of female children. Lay summaryChildhood diffuse brainstem glioma (dBSG) is a rare tumor with a poor prognosis. Any tumor-directed surgical intervention is difficult. Magnetic resonance imaging forms the mainstay of diagnosis and radiation therapy has remained the backbone of therapy. In this 10-year retrospective study, we compare the outcomes of conformal radiotherapy with conventional therapy in the context of resource-constrained settings. A total of 20 patients with a diagnosis of dBSG were included with a median age at diagnosis of 6.5 years (5.25-8.75). No surgical resection or biopsy was done in any patient. Fifteen (75%) patients received radiotherapy and only 4 (20%) patients received additional chemotherapy. Five (25%) patients did not receive any form of anti-cancer therapy. Median overall survival (OS) was 8 months (95% CI 5.2-10.8). Females were at a 3.4-fold (95% CI 1.0-12.1) higher risk of death than males. Children treated with radiotherapy had a longer OS than untreated children; however, the modality of radiotherapy employed or the addition of chemotherapy did not affect the OS. Radiotherapy, irrespective of the modality, increases the survival of children with dBSG in resource-poor settings. Additionally, socioeconomic concerns need to be addressed in the management of these tumors, especially in the case of female children.


Assuntos
Neoplasias do Tronco Encefálico , Glioma , Neoplasias do Tronco Encefálico/radioterapia , Criança , Feminino , Glioma/radioterapia , Humanos , Imageamento por Ressonância Magnética , Masculino , Estudos Retrospectivos
12.
Microbiol Immunol ; 64(11): 737-746, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32930410

RESUMO

An important toxin-antitoxin (TA) system hok/sok, encoded by R1 plasmid of Escherichia coli, is involved in the post segregation killing of cells that have lost the plasmid. The lethal properties of hok protein have been utilized for the environmental containment of microbes and the development of potential vaccine candidates. This study aimed to demonstrate the potent anti-microbial property of a 19 amino acid (AA) long N-terminal fragment of hok peptide. This was accomplished by designing a conditional suicide system based on hok gene expression cloned in an anhydrotetracycline (aTc) inducible vector - pASK75. Heat shock and electroporation were utilized for the transformation of Escherichia coli and Vibrio cholerae cells, respectively. The minimal induction concentration (MId C) of aTc, determined by analyzing the expression of green fluorescent protein cloned separately into pASK75 vector, was 30 ng/mL. As hok gene was synthesized de novo (using recombinant polymerase chain reaction) in our study, various random sized hok fragments were generated (as a result of the error-prone nature of Taq polymerase). The smallest hok fragment able to bring about effective antimicrobial killing was a 19 AA long N-terminal fragment of hok having the wild type sequence, except for the carboxy terminus AA residue. The MId C of aTc in our experiments was 6-fold lower than previously reported, making our bacterial clones suitable for use in mammalian systems as potential vaccine candidates. Based on our experiments, we hypothesize the 19 AA long N-terminal fragment of hok peptide to be the smallest possible hok fragment sufficient to bring about effective antimicrobial killing.


Assuntos
Aminoácidos/metabolismo , Antibacterianos/farmacologia , Clonagem Molecular , Vetores Genéticos/genética , Proteínas Citotóxicas Formadoras de Poros/farmacologia , Tetraciclinas/farmacologia , Escherichia coli/genética , Proteínas de Escherichia coli/genética , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Proteínas de Fluorescência Verde/genética , Plasmídeos/genética , Proteínas Recombinantes , Vibrio cholerae
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