Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 47
Filtrar
1.
Bioorg Med Chem Lett ; 111: 129888, 2024 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-39002937

RESUMO

Trinucleotide repeat expansions fold into long, stable hairpins and cause a variety of incurable RNA gain-of-function diseases such as Huntington's disease, the myotonic dystrophies, and spinocerebellar ataxias. One approach for treating these diseases is to bind small molecules to these structured RNAs. Both Huntington's disease-like 2 (HDL2) and myotonic dystrophy type 1 (DM1) are caused by a r(CUG) repeat expansion, or r(CUG)exp. The RNA folds into a hairpin structure with a periodic array of 1 × 1 nucleotide UU loops (5'CUG/3'GUC; where the underlined nucleotides indicate the Us in the internal loop) that sequester various RNA-binding proteins (RBPs) and hence the source of its gain-of-function. Here, we report nuclear magnetic resonance (NMR)-refined structures of single 5'CUG/3'GUC motifs in complex with three different small molecules, a di-guandinobenzoate (1), a derivative of 1 where the guanidino groups have been exchanged for imidazole (2), and a quinoline with improved drug-like properties (3). These structures were determined using NMR spectroscopy and simulated annealing with restrained molecular dynamics (MD). Compounds 1, 2, and 3 formed stacking and hydrogen bonding interactions with the 5'CUG/3'GUC motif. Compound 3 also formed van der Waals interactions with the internal loop. The global structure of each RNA-small molecule complexes retains an A-form conformation, while the internal loops are still dynamic but to a lesser extent compared to the unbound form. These results aid our understanding of ligand-RNA interactions and enable structure-based design of small molecules with improved binding affinity for and biological activity against r(CUG)exp. As the first ever reported structures of a r(CUG) repeat bound to ligands, these structures can enable virtual screening campaigns combined with machine learning assisted de novo design.


Assuntos
RNA , Bibliotecas de Moléculas Pequenas , Expansão das Repetições de Trinucleotídeos , RNA/química , RNA/metabolismo , Bibliotecas de Moléculas Pequenas/química , Bibliotecas de Moléculas Pequenas/farmacologia , Bibliotecas de Moléculas Pequenas/síntese química , Humanos , Conformação de Ácido Nucleico , Estrutura Molecular , Espectroscopia de Ressonância Magnética , Quinolinas/química , Modelos Moleculares
2.
Retina ; 2024 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-39151183

RESUMO

PURPOSE: To evaluate high-risk histopathological features (HRHF) following primary enucleation of eyes with retinoblastoma (RB) and assess the patient outcomes across continents. METHODS: Retrospective study of 1426 primarily enucleated RB eyes from five continents. RESULTS: Of all, 923 (65%) were from Asia (AS), 27 (2%) from Australia (AUS), 120 (8%) from Europe (EUR), 162 (11%) from North America (NA), and 194 (14%) from South America (SA). Based on the continent (AS vs. AUS vs. EUR vs. NA vs. SA), the histopathology features included massive choroidal invasion (31% vs. 7% vs. 13% vs. 19% vs. 27%, p=0.001), post-laminar optic nerve invasion (27% vs. 0% vs. 16% vs. 21% vs. 19%, p=0.0006), scleral infiltration (5% vs. 0% vs. 4% vs. 2% vs. 7%, p=0.13), and microscopic extrascleral infiltration (4% vs. 0% vs. <1% vs. <1% vs. 4%, p=0.68). Adjuvant chemotherapy with/without orbital radiotherapy was given in 761 (53%) patients. Based on Kaplan-Meier estimates in different continents (AS vs. AUS vs. EUR vs. NA vs. SA), the 6-year risk of orbital tumor recurrence was 5% vs. 2% vs. 0% vs. 0% vs. 12% (p<0.001), systemic metastasis was reported in 8% vs. 5% vs. 2% vs. 0% vs. 13% (p=0.001), and death in 10% vs. 3% vs. 2% vs. 0% vs. 11% (p<0.001) patients. CONCLUSION: There is a wide variation in the infiltrative histopathology features of RB across continents, resulting in variable outcomes. SA and AS had a higher risk of orbital tumor recurrence, systemic metastasis, and death compared to AUS, EUR, and NA.

3.
Chembiochem ; 24(4): e202200609, 2023 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-36455103

RESUMO

We have examined the stabilization of higher-order noncanonical G-quadruplex (G4) DNA structures formed by the G-rich sequences in the promoter region of oncogenes such as c-MYC, c-KIT, VEGF and BCl2 by newly synthesized, novel nitrogen-containing aromatics conjugated to xanthone moiety. Compounds with N-heterocyclic substituents such as pyridine (XNiso), benzimidazole (XBIm), quinoxaline (XQX) and fluorophore dansyl (XDan) showed greater effectiveness in stabilizing the G4 DNA as well as selective cytotoxicity for cancer cells (mainly A549) over normal cells both in terms of UV-Vis spectral titrations and cytotoxicity assay. Both fluorescence spectral titrimetric measurements and circular dichroism (CD) melting experiments further substantiated the G4 stabilization phenomenon by these small-molecular ligands. In addition, these compounds could induce the formation of parallel G4 structures in the absence of any added salt condition in Tris⋅HCl buffer at 25 °C. In a polymerase stop assay, the formation of stable G4 structures in the promoter of oncogenes and halting of DNA synthesis in the presence of the above-mentioned compounds was demonstrated by using oncogene promoter as the DNA synthesis template. Apoptosis-mediated cell death of the cancer cells was proved by Annexin V-PI dual staining assay and cell-cycle arrest occurred in the S phase of the cell cycles. The plausible mode of binding involves the stacking of the xanthone core on the G4 DNA plane with the possibility of interaction with the 5'-overhang as indicated by molecular dynamics simulation studies.


Assuntos
Quadruplex G , Neoplasias , DNA/química , Simulação de Dinâmica Molecular , Ligantes
4.
J Chem Inf Model ; 62(24): 6411-6422, 2022 12 26.
Artigo em Inglês | MEDLINE | ID: mdl-35687766

RESUMO

DNA can adopt various distinct structural motifs, such as quadruplex, duplex, i-motifs, etc. which have multifarious applications in biomedical therapeutics. Quadruplex-duplex hybrids (QDHs) consist of the juxtaposed quadruplex and duplex motifs and are thermally stable and biologically relevant. Selective binding toward these secondary structures plays an important role in the evaluation of the structure-specific ligands. Herein, several small molecules containing anthraquinone conjugated oligopyrrole, oligoimidazole, and pyrrole-imidazole derivatives have been screened for the binding of the quadruplex-duplex nucleic acid hybrids formed in PIM1 sequences through docking and molecular dynamics (MD) simulation studies. The binding interaction of the anthraquinone polypyrrole ligands has also been checked by performing different biophysical experiments. PIM1, being a coactivator of the MYC oncogene, can be targeted by these small molecules to control MYC expression which is overexpressed in the majority of human cancer cells. Accordingly, these cancer cell-specific and blood-compatible anthraquinone conjugated oligopyrrole ligands can be employed for anticancer therapeutic applications. Thus, the structure-activity relationship (SAR) of the screened ligands manifested prudent structural information for designing PIM1 QDHs targeting small molecules.


Assuntos
Quadruplex G , Ácidos Nucleicos , Humanos , Polímeros , Ligantes , Pirróis/farmacologia , Imidazóis/farmacologia , Simulação de Dinâmica Molecular , Antraquinonas/farmacologia , Proteínas Proto-Oncogênicas c-pim-1
5.
Bioconjug Chem ; 28(2): 341-352, 2017 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-28165710

RESUMO

Metal based salen complexes have been considered as an important scaffold toward targeting of DNA structures. In the present work, we have synthesized nickel(II) and palladium(II) salen and salphen complexes by using readily available fluorescein as the backbone to provide an extended aromatic surface. The metal complexes exhibit affinity toward the human telomeric G-quadruplex DNA with promising inhibition of telomerase activity. This has been ascertained by their efficiency in the long term cell proliferation assay which showed significant cancer cell toxicity in the presence of the metal complexes. Confocal microscopy showed cellular internalization followed by localization in the nucleus and mitochondria. Considerable population at the sub-G1 phase of the cell cycle showed cell death via apoptotic pathway.


Assuntos
DNA/química , Fluoresceína/química , Quadruplex G/efeitos dos fármacos , Níquel/química , Compostos Organometálicos/farmacologia , Paládio/química , Telomerase/antagonistas & inibidores , Células A549 , Apoptose/efeitos dos fármacos , DNA/metabolismo , Inibidores Enzimáticos/química , Inibidores Enzimáticos/metabolismo , Inibidores Enzimáticos/farmacologia , Etilenodiaminas/química , Células HEK293 , Humanos , Simulação de Acoplamento Molecular , Compostos Organometálicos/química , Compostos Organometálicos/metabolismo , Fenilenodiaminas/química
6.
J Dairy Sci ; 99(6): 4146-4153, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27040785

RESUMO

The objective of this study was to determine the effect of mineral chelator addition during skim milk powder (SMP) manufacture on the solubility, turbidity, soluble protein, and heat stability (HS). Three chelators (sodium citrate dihydrate, sodium polyphosphate, and disodium EDTA) at 3 different concentrations (5, 15, and 25mM) were added to skim milk concentrate (30% total solids), and the pH was adjusted to 6.65 before spray drying to produce SMP. Spray-dried SMP samples were tested for solubility index (SI). Additionally, samples were reconstituted to contain 9% total solids, adjusted to pH 7.0, and tested for turbidity, protein content from supernatants of ultracentrifuged samples, and HS. Lower SI values were observed for samples treated with 5mM disodium EDTA and sodium polyphosphate than control samples or samples with 5mM sodium citrate dihydrate. Furthermore, lower SI values were observed with an increased level of chelating agents regardless of chelator type. A decreased turbidity value was found with increasing levels of mineral chelating salt treatment. Low turbidity with increasing levels of added chelators may be associated with the dissociation of caseins from micelles. Furthermore, higher protein content was observed in supernatants of ultracentrifuged samples treated with increased level of chelators as compared with the control sample. Higher HS was observed in samples treated with 5mM compared with samples treated with 25mM mineral chelator. The results suggest improved solubility and HS upon addition of mineral chelators to SMP during its manufacture.


Assuntos
Leite/química , Pós/química , Animais , Caseínas , Quelantes , Concentração de Íons de Hidrogênio , Micelas , Proteínas do Leite , Minerais
7.
Orbit ; 33(1): 29-32, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24195743

RESUMO

PURPOSE: To describe the clinical profile and surgical management of patients with lacrimal sac rhinosporidiosis. METHODS: This is a retrospective interventional case series. Eighteen patients, who were clinically diagnosed as isolated lacrimal sac rhinosporidiosis between October 2009 to January 2012, were included in the study. Detailed history, including whether there was exposure to stagnant bathing water, was noted. All patients underwent modified dacryocystorhinostomy (DCR) under general anaesthesia. RESULT: Out of 18 patients, 14 were male and 4 were female. Rhinosporidiosis was more prevalent in the 25 to 34 years age group. The most common clinical presentation was a doughy swelling over the lacrimal sac area, present in all cases. Twelve patients (66.67%) had a history of bathing in stagnant water. After modified DCR operation, all patients were followed for one year and only two patients had recurrence of their disease. CONCLUSION: Patients with lacrimal sac rhinosporidiosis usually present with a soft, doughy swelling in the lacrimal sac area. Bathing in stagnant water is a common risk factor. A modified DCR yields excellent outcomes.


Assuntos
Dacriocistorinostomia/métodos , Infecções Oculares Parasitárias/diagnóstico , Doenças do Aparelho Lacrimal/diagnóstico , Aparelho Lacrimal/parasitologia , Rinosporidiose/diagnóstico , Adolescente , Adulto , Distribuição por Idade , Anestesia Geral , Animais , Criança , Pré-Escolar , Infecções Oculares Parasitárias/parasitologia , Infecções Oculares Parasitárias/cirurgia , Feminino , Humanos , Doenças do Aparelho Lacrimal/parasitologia , Doenças do Aparelho Lacrimal/cirurgia , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Rinosporidiose/parasitologia , Rinosporidiose/cirurgia , Rhinosporidium/isolamento & purificação , Distribuição por Sexo , Resultado do Tratamento , Adulto Jovem
8.
bioRxiv ; 2024 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-38948793

RESUMO

Trinucleotide repeat expansions fold into long, stable hairpins and cause a variety of incurable RNA gain-of-function diseases such as Huntington's disease, the myotonic dystrophies, and spinocerebellar ataxias. One approach for treating these diseases is to bind small molecules to the structured RNAs. Both Huntington's disease-like 2 (HDL2) and myotonic dystrophy type 1 (DM1) are caused by a r(CUG) repeat expansion, or r(CUG)exp. The RNA folds into a hairpin structure with a periodic array of 1×1 nucleotide UU loops (5'CUG/3'GUC; where the underlined nucleotides indicate the Us in the internal loop) that sequester various RNA-binding proteins (RBP) and hence the source of its gain-of-function. Here, we report NMR-refined structures of single 5'CUG/3'GUC motifs in complex with three different small molecules, a di-guandinobenzoate (1), a derivative of 1 where the guanidino groups have been exchanged for imidazole (2), and a quinoline with improved drug-like properties (3). These structures were determined using nuclear magnetic resonance (NMR) spectroscopy and simulated annealing with restrained molecular dynamics (MD). Compounds 1, 2, and 3 formed stacking and hydrogen bonding interactions with the 5'CUG/3'GUC motif. Compound 3 also formed van der Waals interactions with the internal loop. The global structure of each RNA-small molecule complexes retains an A-form conformation, while the internal loops are still dynamic but to a lesser extent compared to the unbound form. These results aid our understanding of ligand-RNA interactions and enable structure-based design of small molecules with improved binding affinity for and biological activity against r(CUG)exp. As the first ever reported structures of RNA r(CUG) repeats bound to ligands, these structures can enable virtual screening campaigns combined with machine learning assisted de novo design.

9.
Am J Ophthalmol ; 268: 399-408, 2024 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-39332513

RESUMO

PURPOSE: To compare the clinical outcomes of children with unilateral retinoblastoma (Rb) and high-risk histopathology features (HRHF) following upfront enucleation with/without adjuvant chemotherapy, and investigate cases locally considered non-HRHF but converted to a standardized HRHF definition. DESIGN: Retrospective multinational clinical cohort study. METHODS: Children with Rb who presented to 21 centers from 12 countries between 2011-2020, and underwent primary enucleation were recruited. Centers retrieved clinical data and were asked to report detailed histopathology findings, as well as indicate cases defined locally as high-risk. For analysis, only unilateral cases with standardized HRHF, defined as retrolaminar optic nerve invasion, massive choroidal invasion, scleral invasion, anterior-segment involvement, and/or combined nonmassive choroidal and prelaminar/laminar optic nerve invasion, were included. Main outcome measures included orbital tumor recurrence, systemic metastasis, survival and number, and outcome of cases converted to standardized HRHF. RESULTS: A total of 600 children presenting to 14 centers in 9 countries were included. Of these, 505 (84.2%) were considered locally as HRHF and received adjuvant chemotherapy. After a median follow-up period of 39.2 ± 1.6 months (range: 0.8-60.0 months), 36 (6.0%) had orbital tumor recurrence, 49 (8.2%) metastasis, and 72 (12.0%) children died. Children not receiving adjuvant chemotherapy were at significantly increased risk of orbital tumor recurrence, metastasis, and death (P ≤ .002). Of the study children, 63/600 (10.5%) were considered locally non-HRHF, but converted to standardized HRHF and included in the analysis. Of these, 6/63 (9.5%) had orbital tumor recurrence, 5/63 (7.9%) metastasis, and 6/63 (9.5%) children died. Isolated minor choroidal invasion with prelaminar/laminar optic nerve invasion was reported in 114 (19.0%) children, but considered locally as HRHF only in 68/114 (59.6%). Of these, 6/114 (5.3%) children developed metastasis and subsequently died, yielding a number needed to treat of 15. CONCLUSION: Based on this multinational cohort of children with Rb, we recommend the use of adjuvant chemotherapy following upfront enucleation and diagnosis of HRHF. Variation exists worldwide among centers when defining HRHF, resulting in adverse patient outcomes, warranting standardization.

10.
Invest Ophthalmol Vis Sci ; 65(4): 39, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38662390

RESUMO

Purpose: Little is known regarding differences in childhood growth between somatic and heritable retinoblastoma (Rb) populations. We aimed to compare childhood growth parameters between somatic and heritable Rb cohorts at birth and at time of diagnosis with Rb. Methods: A multinational, longitudinal cohort study was conducted with patients from 11 centers in 10 countries who presented with treatment naïve Rb from January to December 2019. Variables of interest included age, sex, and size characteristics at birth and at time of presentation, as well as germline mutation status. After Bonferroni correction, results were statistically significant if the P value was less than 0.005. Results: We enrolled 696 patients, with 253 analyzed after exclusion criteria applied. Between somatic (n = 39) and heritable (n = 214) Rb cohorts, with males and females analyzed separately, there was no significant difference in birth weight percentile, weight percentile at time of diagnosis, length percentile at time of diagnosis, weight-for-length percentile at time of diagnosis, or change of weight percentile from birth to time of diagnosis. Patients with heritable Rb had a smaller mean weight percentile at birth and smaller mean weight and length percentiles at time of diagnosis with Rb, although this difference was not statistically significant. All cohorts experienced a slight negative change of weight percentile from birth to time of diagnosis. No cohort mean percentiles met criteria for failure to thrive, defined as less than the 5th percentile. Conclusions: Children with Rb seem to have normal birth and childhood growth patterns. There is no definitive evidence that somatic or heritable Rb has a biological or environmental impact on childhood growth parameters.


Assuntos
Peso ao Nascer , Neoplasias da Retina , Retinoblastoma , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Estatura/genética , Peso Corporal , Desenvolvimento Infantil/fisiologia , Mutação em Linhagem Germinativa , Estudos Longitudinais , Neoplasias da Retina/genética , Retinoblastoma/genética , Estudos Retrospectivos
11.
J Biomol Struct Dyn ; : 1-8, 2023 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-37922129

RESUMO

Flavonoids, low molecular weight polyphenolic compounds, are important natural products that belong to plant secondary metabolites. They have diverse biomedical applications such as antioxidative, anti-inflammatory, enzyme inhibitory, antimutagenic, anticarcinogenic, aromatase inhibitory effects, etc. Some of the flavonoids have been exported for bindings with certain DNA and tRNA structures both experimentally and computationally. RNA-DNA hybrid (RDH) falls into an important category of noncanonical nucleic acid structures that have many important biological functions. We have investigated the interaction of RDH structures with some of the dietary flavonoids with the aid of computational methods such as docking and molecular dynamics simulation. The presence of the - OH group on the ligand and the availability of a proper binding pocket in the macromolecule are the two main factors driving the binding preference. Thus, this computationally guided report explains the binding of the flavonoids with RDH structures to assist the researchers in designing noncanonical nucleic acid-targeted drug molecules.Communicated by Ramaswamy H. Sarma.

12.
Oman J Ophthalmol ; 16(1): 148-150, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37007254

RESUMO

A 36-year-old male patient presented with a firm swelling in the left lacrimal sac region with a history of recurrent episodes of acute dacryocystitis, which partly resolved with systemic antibiotics. Computed tomography showed diffuse soft tissue mass without bony erosion in the same area. Incisional biopsy confirmed diffuse large cell lymphoma of non-Hodgkin's type by histopathology and immunohistochemistry. Oncologists did not detect systemic involvement, and the patient received six cycles of cyclophosphamide, hydroxydaunorubicin, oncovin, and prednisolone (CHOP). Epiphora was resolved, and no recurrence of the lesion was seen with subsequent dacryocystorhinostomy with intubation and was in good health for up to 3 years of follow-up. Although primary lacrimal sac lymphoma is a rare entity, high suspicion, and prompt action in atypical cases can save lives from aggressive diffuse large cell lymphoma.

13.
ACS Pharmacol Transl Sci ; 6(4): 546-566, 2023 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-37082748

RESUMO

Xanthone is an important scaffold for various medicinally relevant compounds. However, it has received scant attention in the design of agents that are cytotoxic to cancer cells via targeting the stabilization of G-quadruplex (G4) nucleic acids. Specific G4 DNA recognition against double-stranded (ds) DNA is receiving epoch-making interest for the development of G4-mediated anticancer agents. Toward this goal, we have synthesized xanthone-based derivatives with various functionalized side-arm substituents that exhibited significant selectivity for G4 DNA as compared to dsDNA. The specific interaction has been demonstrated by performing various biophysical experiments. Based on the computational study as well as the competitive ligand binding assay, it is inferred that the potent compounds exhibit an end-stacking mode of binding with G4 DNA. Additionally, compound-induced conformational changes in the flanking nucleotides form the binding pocket for effective interaction. Selective action of the compounds on cancer cells suggests their effectiveness as potent anti-cancer agents. This study promotes the importance of structure-based screening approaches to get molecular insights for new scaffolds toward desired specific recognition of non-canonical G4 DNA structures.

14.
Eye (Lond) ; 37(5): 966-970, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-35361938

RESUMO

BACKGROUND/OBJECTIVES: Retinoblastoma is a common childhood intraocular malignancy, the bilateral form of which most commonly results from a de novo germline pathogenic variant in the RB1 gene. Both advanced maternal age and decreasing birth order are known to increase the risk of de novo germline pathogenic variants, while the influence of national wealth is understudied. This cohort study aimed to retrospectively observe whether these factors influence the ratio of bilateral retinoblastoma cases compared to unilateral retinoblastoma, thereby inferring an influence on the development of de novo germline pathogenic variants in RB1. SUBJECTS/METHODS: Data from 688 patients from 11 centres in 10 countries were analysed using a series of statistical methods. RESULTS: No associations were found between advanced maternal age, birth order or GDP per capita and the ratio of bilateral to unilateral retinoblastoma cases (p values = 0.534, 0.201, 0.067, respectively), indicating that these factors do not contribute to the development of a de novo pathogenic variant. CONCLUSIONS: Despite a lack of a definitive control group and genetic testing, this study demonstrates that advanced maternal age, birth order or GDP per capita do not influence the risk of developing a bilateral retinoblastoma.


Assuntos
Neoplasias da Retina , Retinoblastoma , Criança , Humanos , Ordem de Nascimento , Estudos de Coortes , Idade Materna , Neoplasias da Retina/epidemiologia , Neoplasias da Retina/genética , Neoplasias da Retina/patologia , Retinoblastoma/epidemiologia , Retinoblastoma/genética , Retinoblastoma/patologia , Estudos Retrospectivos , Fatores de Risco , Feminino
15.
Br J Ophthalmol ; 107(12): 1818-1822, 2023 11 22.
Artigo em Inglês | MEDLINE | ID: mdl-36113955

RESUMO

BACKGROUND: Rates of care abandonment for retinoblastoma (RB) demonstrate significant geographical variation; however, other variables that place a patient at risk of abandoning care remain unclear. This study aims to identify the risk factors for care abandonment across a multinational set of patients. METHODS: A prospective, observational study of 692 patients from 11 RB centres in 10 countries was conducted from 1 January 2019 to 31 December 2019. Multivariate logistic regression was used to identify risk factors associated with higher rates of care abandonment. RESULTS: Logistic regression showed a higher risk of abandoning care based on country (high-risk countries include Bangladesh (OR=18.1), Pakistan (OR=45.5) and Peru (OR=9.23), p<0.001), female sex (OR=2.39, p=0.013) and advanced clinical stage (OR=4.22, p<0.001). Enucleation as primary treatment was not associated with a higher risk of care abandonment (OR=0.59, p=0.206). CONCLUSION: Country, advanced disease and female sex were all associated with higher rates of abandonment. In this analysis, enucleation as the primary treatment was not associated with abandonment. Further research investigating cultural barriers can enable the building of targeted retention strategies unique to each country.


Assuntos
Neoplasias da Retina , Retinoblastoma , Humanos , Feminino , Retinoblastoma/epidemiologia , Retinoblastoma/terapia , Estudos Prospectivos , Recusa do Paciente ao Tratamento , Estudos Retrospectivos , Fatores de Risco , Neoplasias da Retina/epidemiologia , Neoplasias da Retina/terapia
16.
Mitochondrial DNA B Resour ; 7(11): 1939-1941, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36386021

RESUMO

The first complete mitochondrial genome sequencing of Asiatic Water snake or Checkered Keelback or Fowlea piscator (=Xenochrophis piscator) was carried out using Next-Generation Sequencing technology. The complete mitochondrial genome of Asiatic Water snake is 16,999bp long with a base composition of 33% A, 28% T, 12% G and 27% C, with a GC content of 39%. Like the typical snake mitochondrial genome, F. piscator also shows relatively similar mitogenome arrangement comprising 37 genes including 13 protein-coding genes, 22 tRNA genes, two rRNA genes and two non-coding regions or a duplicated control region (D-Loop) along with an origin of replication. Nine genes including eight tRNAs and NAD6 were encoded on the Light or L-strand. Phylogenetic analyses using the complete mitochondrial genome of F. piscator demonstrate a close relationship with the family Colubridae and sub family Natricinae.

17.
ChemMedChem ; 17(22): e202200436, 2022 11 18.
Artigo em Inglês | MEDLINE | ID: mdl-36161519

RESUMO

Anthraquinone-based compounds are well-known as duplex DNA as well as G-quadruplex DNA binders. Implications of various anthraquinone derivatives for specific recognition of G-quadruplex DNA over duplex DNA is a 'challenging' research work that requires adequate experience with molecular design. To address this important issue, we designed and synthesized ten new 2,6-disubstituted anthraquinone-based derivatives with different functionalized piperazinyl side-chains. Among these, particular compounds with certain distant groups have shown selective and significant binding affinities toward the c-MYC and c-KIT G-quadruplex DNA over the duplex DNA, as noticed from various biophysical experiments. The structural difference of quadruplex and duplex DNA was utilized to probe these derivatives for the end-stacking mode of binding with G-quadruplex DNA. The ability of the ligands to halt DNA synthesis by stabilizing G-quadruplex structures is one of the crucial points to further apply them for quadruplex-mediated anti-cancer therapeutics. Interestingly, these ligands trigger apoptosis to exhibit selective cytotoxicity toward cancer cells over normal cells. This was further evidenced by ligand-induced cell cycle arrest as well as cellular apoptotic morphological changes. These blood-compatible ligands provided detailed structure-activity relationship approaches for the molecular design of anthraquinone-based G-quadruplex binders.


Assuntos
Antineoplásicos , Quadruplex G , Neoplasias , DNA/química , Ligantes , Antineoplásicos/farmacologia , Antineoplásicos/química , Antraquinonas/farmacologia
18.
Oman J Ophthalmol ; 15(1): 81-84, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35388258

RESUMO

Ocular surface squamous neoplasia (OSSN) is the most common nonpigmented ocular surface neoplasm. Interferon-alpha (IFNα)-2b has been proved to be an effective immunotherapeutic agent to treat OSSN. We have used intralesional and topical (36 µg/ml) pegylated (peg) IFNα-2a to treat a recurrent surgically failed case of OSSN instead of IFNα-2b. In this case report, we have shared our initial experience with the novel use of peg-IFNα-2a to treat OSSN. According to our brief clinical experience, peg-IFNα-2a is nontoxic to ocular surface and has a promising role to treat OSSN.

19.
J Phys Chem B ; 125(21): 5489-5501, 2021 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-34029082

RESUMO

The interactions of intermolecular G-quadruplex RNA and small molecules have been investigated by computational studies. Various anthraquinone, bisbenzimidazole, and carbazole-benzimidazole based ligands have shown a distinct preference to G-quadruplex structures as opposed to the corresponding duplex forms of DNA that were docked with telomeric G-quadruplex RNA. The comparative binding study of such ligands with G-quadruplex (G4) RNA showed higher binding affinities toward carbazole-benzimidazole ligands than those of the anthraquinone and bisbenzimidazole based ligands. A molecular dynamics simulation study was used to examine quadruplex-ligand interactions. Analysis of the binding free energy indicated the formation of the thermodynamically favorable RNA-ligand complex. The formation of several H-bonding interactions and the change of the solvent accessible surface area (SASA) also support the effective binding of the carbazole-benzimidazole ligands with G4 RNA structures. Thus, the library screening approach has assisted in getting a structure-activity relationship for the selected small molecules toward the G-quadruplex RNA binding, which can be applied in the targeting of G-quadruplex RNA medicated anticancer therapeutics.


Assuntos
Quadruplex G , Simulação de Dinâmica Molecular , Ligantes , Simulação de Acoplamento Molecular , RNA , Telômero
20.
Eur J Ophthalmol ; : 11206721211048109, 2021 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-34581203

RESUMO

PURPOSE: To describe a minimally invasive technique of harvesting fascia lata, and also to analyze the clinical uses and the outcome of fascia lata in Ophthalmic Plastic and Reconstructive surgery. METHODS: This interventional study was done in three tertiary care eye hospitals in Bangladesh from July 2014 to June 2020. We obtained autologous fascia lata for the correction of congenital ptosis with poor levator function (⩽4 mm), covering the ciliary staphyloma, repair of the extruded implant following anophthalmic socket surgery, and was also used to wrap the orbital implant after enucleation. Preserved FL was used only for children before 6 years of age for the treatment of congenital ptosis. RESULTS: Out of 60 subjects, 38 (63.3%) were male and 22 (36.7%) were female. Autogenous fascia lata was used for frontalis brow suspension (FBS) in 25 (41.67%) patients of congenital ptosis with poor levator function, as patch graft in ciliary staphyloma (11 cases, 18.3%), to wrap orbital implant following enucleation in intraocular malignancies (nine cases, 15%), to repair of implant extrusion following evisceration (five cases, 8.3%), and as fascial sling to correct recurrent paralytic ectropion (one case, 1.67%). Allogeneic or preserved fascia lata was used to correct congenital ptosis in patients less than 6 years of age (nine cases, 15%). Mean follow-up time was 5.32 months. CONCLUSION: Fascia lata (autogenous and allogeneic preserved) has varied uses in ophthalmic plastic surgery. Harvesting fascia lata (FL) using with minimally invasive method was successful with the least scar on the thigh to correct congenital ptosis, ciliary staphyloma, repair of extruded implant, and in wrapping implant after enucleation to get better cosmesis and motility.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA