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1.
Phys Chem Chem Phys ; 26(6): 5387-5398, 2024 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-38270198

RESUMO

Here, we report a comparison study on the synthesis and characterization of perovskite SrSnO3 (SSO) and Sr2SnO4 (S2SO). Rietveld refinement studies were performed on both prepared samples and suggest that they crystallized in cubic (SSO) and tetragonal (S2SO) structures. Fourier-transform infrared (FTIR) and Raman spectroscopy studies supported the XRD observations. Improved dielectric parameters were observed for S2SO over SSO due to differences in dislocation density, larger crystallite size, and denser microstructure. The electrical conduction and relaxation processes followed the Arrhenius type in both samples through the migration of oxygen vacancies via the Sn-site and the transfer of electrons between the Sn sites in two different temperature regions. These processes in the samples occurred via correlated barrier hopping (CBH) in SSO and the non-overlapping of small-polaron tunnelling (NSPT) in S2SO. The conduction and relaxation processes had similar sources of charge carriers but differed in the concentration and mobility of charge carriers. The presented materials can be utilized for dielectric capacitors, sensors, and mixed ionic and electronic conductor-based electrodes in IT-SOFC applications.

2.
Rheumatol Int ; 44(5): 819-829, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38082159

RESUMO

Antiphospholipid antibodies (APLA) are present in one-third of systemic lupus erythematosus (SLE) patients, and they are associated with both criteria and non-criteria manifestations. We studied the prevalence, clinical associations, and impact on mortality of APLA in SLE patients from India. Among the Indian SLE inception cohort (INSPIRE), patients who had data on all five routinely performed APLAs [lupus anticoagulant (LA), IgG and IgM anticardiolipin antibody (aCL) and anti-ß2-glycoprotein I(ß2GPI)] at enrolment were selected. Patients were divided into four categories based on the presence/absence of APLA associated manifestations and presence/absence of the APLA viz SLE-APS, SLE-APLA, SLE: events but no APLA, and SLE: no events, no APLA (reference group). 1035 SLE patients at least 1 APLA antibody was detected in 372 (35.9%). LA was present in 206 (19.9%), aCL in 126 (12.2%) and ß2-GPI in 178 (17.2%). There were 88 thrombotic events in 83 patients (8.0%); 73 (82.9%) being arterial; APLA positivity was present in 37 (44.6%) [AOR 1.70 (1.054, 2.76)]. SLE-APS patients were younger and had higher mortality [AOR 4.11 (1.51, 11.3)], neuropsychiatric and hematologic disease. SLE-APLA also had a higher mortality rate [AOR 2.94 (1.06, 8.22)] than the reference group. The mortality was highest in the subset of patients with thrombotic events in the presence of APLA [AOR 7.67 (1.25, 46.9)]. The mere presence of APLA also conferred higher mortality even in the absence of thrombotic events [AOR 3.51 (1.43, 8.63)]. Hematologic manifestations (36.1%) were the most common non-criteria-manifestation. One-third of SLE patients have APLA and its presence is associated with non-criteria hematologic manifestations, arterial thrombosis and higher mortality rate.


Assuntos
Síndrome Antifosfolipídica , Lúpus Eritematoso Sistêmico , Trombose , Humanos , Anticorpos Antifosfolipídeos , Anticorpos Anticardiolipina , Lúpus Eritematoso Sistêmico/complicações , Síndrome Antifosfolipídica/complicações , Inibidor de Coagulação do Lúpus
3.
J Am Chem Soc ; 145(1): 422-435, 2023 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-36537351

RESUMO

The development of an efficient photocatalyst for C2 product formation from CO2 is of urgent importance toward the deployment of solar-fuel production. Here, we report a template-free, cost-effective synthetic strategy to develop a carbazole-derived porous organic polymer (POP)-based composite catalyst. The composite catalyst is comprised of In2.77S4 and porous organic polymer (POP) and is held together by induced-polarity-driven electrostatic interaction. Utilizing the synergy of the catalytically active In centers and light-harvesting POPs, the catalyst showed 98.9% selectivity toward the generation of C2H4, with a formation rate of 67.65 µmol g-1 h-1. Two different oxidation states of the In2.77S4 spinel were exploited for the C-C coupling process, and this was investigated by X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), and density functional theory (DFT) calculations. The role of POP was elucidated via several photophysical and photoelectrochemical studies. The electron transfer was mapped by several correlated approaches, which assisted in establishing the Z-scheme mechanism. Furthermore, the mechanism of C2H4 formation was extensively investigated using density functional theory (DFT) calculations from multiple possible pathways.

4.
Chemistry ; 29(63): e202301932, 2023 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-37632841

RESUMO

A reaction of fundamental and commercial importance is acetylene semi-hydrogenation. Acetylene impurity in the ethylene feedstock used in the polyethylene industry poisons the Ziegler-Natta catalyst which adversely affects the polymer quality. Pd based catalysts are most often employed for converting acetylene into the main reactant, ethylene, however, it often involves a tradeoff between the conversion and the selectivity and generally requires high temperatures. In this work, bimetallic Pd-Zn nanoparticles capped by hexadecylamine (HDA) have been synthesized by co-digestive ripening of Pd and Zn nanoparticles and studied for semi-hydrogenation of acetylene. The catalyst showed a high selectivity of ~85 % towards ethylene with a high ethylene productivity to the tune of ~4341 µmol g-1 min-1 , at room temperature and atmospheric pressure. It also exhibited excellent stability with ethylene selectivity remaining greater than 85 % even after 70 h on stream. To the best of the authors' knowledge, this is the first report of room temperature acetylene semi-hydrogenation, with the catalyst effecting high amount of acetylene conversion to ethylene retaining excellent selectivity and stability among all the reported catalysts thus far. DFT calculations show that the disordered Pd-Zn nanocatalyst prepared by a low temperature route exhibits a change in the d-band center of Pd and Zn which in turn enhances the selectivity towards ethylene. TPD, XPS and a range of catalysis experiments provided in-depth insights into the reaction mechanism, indicating the key role of particle size, surface area, Pd-Zn interactions, and the capping agent.

5.
Biogerontology ; 24(5): 679-708, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37428308

RESUMO

Aging-induced neurodegenerative diseases (NDs) are significantly increasing health problem worldwide. It has been well documented that oxidative stress is one of the potential causes of aging and age-related NDs. There are no drugs for the treatment of NDs, therefore there is an immediate necessity for the development of strategies/treatments either to prevent or cure age-related NDs. Caloric restriction (CR) and intermittent fasting have been considered as effective strategies in increasing the healthspan and lifespan, but it is difficult to adhere to these routines strictly, which has led to the development of calorie restriction mimetics (CRMs). CRMs are natural compounds that provide similar molecular and biochemical effects of CR, and activate autophagy process. CRMs have been reported to regulate redox signaling by enhancing the antioxidant defense systems through activation of the Nrf2 pathway, and inhibiting ROS generation through attenuation of mitochondrial dysfunction. Moreover, CRMs also regulate redox-sensitive signaling pathways such as the PI3K/Akt and MAPK pathways to promote neuronal cell survival. Here, we discuss the neuroprotective effects of various CRMs at molecular and cellular levels during aging of the brain. The CRMs are envisaged to become a cornerstone of the pharmaceutical arsenal against aging and age-related pathologies.


Assuntos
Restrição Calórica , Doenças Neurodegenerativas , Humanos , Neuroproteção , Doenças Neurodegenerativas/prevenção & controle , Fosfatidilinositol 3-Quinases , Envelhecimento/metabolismo
6.
J Acoust Soc Am ; 154(6): 3615-3626, 2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-38047690

RESUMO

The present work investigates the propagation of Love wave in a flexoelectric piezoelectric-viscoelastic stratum imperfectly bonded to a piezoelectric-viscoelastic substrate. To study the impact of imperfect interfaces, the non-traditional boundary conditions for two different types of imperfect interfaces have been taken into account. The frequency relation has been obtained in complex form employing a suitable variable separable technique. The dispersion and damping equations of Love wave have been analytically determined in the closed form by separating the real and imaginary part of the frequency relation for two distinct interfaces, i.e., mechanically compliant and dielectrically weakly/highly conducting interfaces in both electrically open and electrically short cases. Numerical calculations are carried out to reveal the impact of the width of stratum, imperfectness parameter, flexoelectric parameters, and flexoelectric loss moduli on the phase velocity and attenuation coefficient of Love wave and are also depicted through graphs for both the interfaces. For validation purposes, the expressions derived as a result of the present study are matched with the standard Love wave equation.

7.
J Assoc Physicians India ; 71(12): 104, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38736065

RESUMO

We read with great interest the article "the deadly duo of hypertension and diabetes in India: further affirmation from a new epidemiological study" by Metri et al.1 They rightly pointed out that the prevalence of hypertension in Indian patients with type 2 diabetes patients is high and therefore early screening and management of hypertension should be included in the treatment of patients with type 2 diabetes. We wish to share our study findings on the prevalence of hypertension in newly onset diabetes mellitus (DM). We find that the prevalence of hypertension in all males and females with DM was 44.59, 44.34, and 45.16%, respectively.2.


Assuntos
Diabetes Mellitus Tipo 2 , Hipertensão , Humanos , Hipertensão/epidemiologia , Índia/epidemiologia , Diabetes Mellitus Tipo 2/epidemiologia , Diabetes Mellitus Tipo 2/complicações , Prevalência , Masculino , Feminino , Pessoa de Meia-Idade , Adulto
8.
Small ; 18(13): e2106139, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35129312

RESUMO

Though several Pt-free hydrogen evolution reaction (HER) catalysts have been reported, their employment for industry is challenging. Here, a facile pyrolysis method to obtain phase-pure CrP nanoparticles supported on N, P dual-doped carbon (CrP/NPC) is reported to be tuned toward industrial HER. Interestingly, CrP/NPC exhibits excellent HER activity that requires an overpotential of 34 mV to attain a current density of 10 mA cm-2 , which is only 1 mV positive to commercial Pt/C and a potential of 55 mV to achieve a current density of 200 mA cm-2 which is better than Pt/C. In addition, the long-term durability of CrP/NPC is far superior to Pt/C due to the strong interaction between CrP and C support, restricting any agglomeration or leaching. Density functional theory (DFT) calculations suggest that electronic modulation at the interface (CrP/NPC) optimizes the hydrogen adsorption energy. The Cr-Cr bridge site with required density of states near the Fermi level is found to be the active site. Overall, this report provides a practical scheme to synthesize rarely investigated CrP based materials along with a computational mechanistic guideline for electrocatalysis that can be utilized to explore other phosphides for various applications.

9.
Drug Chem Toxicol ; 45(1): 52-60, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31474151

RESUMO

Acetaminophen or N-acetyl-p-amino-phenol (APAP) is a drug which is available over-the-counter for fever and pain. Its overdosing causes oxidative stress and subsequent acute liver damage. In the present study, we scrutinized the protective effect of metformin co-treatment in APAP induced blood and liver sub-acute toxicity. This is a pre-clinical study in which male Wistar Rats (BW: 300 ± 20 g) were orally co-treated with APAP (1 g/kg/day) and metformin (300 mg/kg/day) for 28-days. Pro- and anti-oxidant markers viz reactive oxygen species, protein carbonyl, malondialdehyde (MDA), the ferric reducing ability of plasma (FRAP), plasma membrane redox system(PMRS) and reduced glutathione (GSH) were evaluated in blood. Additionally, in liver tissue, catalase (CAT), superoxide dismutase (SOD), MDA and GST level were also evaluated. Histological study and estimation of alanine aminotransferase (ALT), and aspartate aminotransferase (AST) level in serum were performed. APAP induces pro-oxidant markers as well as reduces anti-oxidant markers in blood and liver. Hepatic tissues degeneration and vacuolization of hepatocytes were evident after APAP treatment. Metformin treatment reduces pro-oxidant markers as well as increases anti-oxidant markers in both tissues. It also improves liver tissue architecture after treatment. The outcome of this study suggests that metformin has protective capability against APAP-induced blood and liver toxicity. Thus, metformin co-treatment with APAP attenuates oxidative stress and its consequences.


Assuntos
Doença Hepática Induzida por Substâncias e Drogas , Metformina , Acetaminofen/toxicidade , Animais , Antioxidantes/metabolismo , Antioxidantes/farmacologia , Doença Hepática Induzida por Substâncias e Drogas/etiologia , Doença Hepática Induzida por Substâncias e Drogas/metabolismo , Doença Hepática Induzida por Substâncias e Drogas/prevenção & controle , Fígado/metabolismo , Masculino , Metformina/toxicidade , Estresse Oxidativo , Ratos , Ratos Wistar
10.
J Proteome Res ; 20(2): 1190-1205, 2021 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-33497241

RESUMO

Pregnancy is characterized by intense physiological and structural alterations in the vagina, cervix, and overlying fetal membranes. High vaginal fluid (HVF) is a proximal fluid that covers the lower part of the female reproductive system and the severity of vaginal pathology often adversely affects pregnancy outcomes. To identify the correlation of vaginal fluid proteome dynamics and physiological changes during the progression of pregnancy, a longitudinal study was performed on 20 pregnant women who delivered a baby in >37 weeks without any complications. SWATH-MS-based label-free quantitative proteomics was performed to profile the HVF proteome at three time points defined as V1 (7-12 weeks), V2 (18-20 weeks), and V3 (26-28 weeks). Linear mixed-effect models were used to estimate protein abundance as a function of the period of gestational age. In this study, we identified 1015 HVF proteins and 61 of them were significantly altered until late second trimester. Our result demonstrates that the HVF proteins reveal gestational age-specific expression patterns and the function of these proteins is associated with tissue remodeling, organ development, and microbial defense. Our study provides an opportunity to monitor the underlying physiology of pregnancy that may be further probed for the biomarker identification in pregnancy-related adverse outcomes. Data are available via ProteomeXchange with identifiers PXD014846 and PXD021811.


Assuntos
Líquidos Corporais , Proteoma , Colo do Útero , Feminino , Humanos , Estudos Longitudinais , Gravidez , Proteoma/genética , Vagina
11.
J Biol Chem ; 295(11): 3466-3484, 2020 03 13.
Artigo em Inglês | MEDLINE | ID: mdl-32005664

RESUMO

Parkinson's disease (PD) is a multifactorial malady and the second most common neurodegenerative disorder, characterized by loss of dopaminergic neurons in the midbrain. A hallmark of PD pathology is the formation of intracellular protein inclusions, termed Lewy bodies (LBs). Recent MS studies have shown that OTU deubiquitinase ubiquitin aldehyde-binding 1 (OTUB1), a deubiquitinating enzyme of the OTU family, is enriched together with α-synuclein in LBs from individuals with PD and is also present in amyloid plaques associated with Alzheimer's disease. In the present study, using mammalian cell cultures and a PD mouse model, along with CD spectroscopy, atomic force microscopy, immunofluorescence-based imaging, and various biochemical assays, we demonstrate that after heat-induced protein aggregation, OTUB1 reacts strongly with both anti-A11 and anti-osteocalcin antibodies, detecting oligomeric, prefibrillar structures or fibrillar species of amyloidogenic proteins, respectively. Further, recombinant OTUB1 exhibited high thioflavin-T and Congo red binding and increased ß-sheet formation upon heat induction. The oligomeric OTUB1 aggregates were highly cytotoxic, characteristic of many amyloid proteins. OTUB1 formed inclusions in neuronal cells and co-localized with thioflavin S and with α-synuclein during rotenone-induced stress. It also co-localized with the disease-associated variant pS129-α-synuclein in rotenone-exposed mouse brains. Interestingly, OTUB1 aggregates were also associated with severe cytoskeleton damage, rapid internalization inside the neuronal cells, and mitochondrial damage, all of which contribute to neurotoxicity. In conclusion, the results of our study indicate that OTUB1 may contribute to LB pathology through its amyloidogenic properties.


Assuntos
Amiloide/química , Enzimas Desubiquitinantes/toxicidade , Neurotoxinas/toxicidade , Doença de Parkinson/patologia , Agregados Proteicos , Citoesqueleto de Actina/metabolismo , Animais , Apoptose/efeitos dos fármacos , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Simulação por Computador , Citoesqueleto/efeitos dos fármacos , Citoesqueleto/metabolismo , Enzimas Desubiquitinantes/química , Modelos Animais de Doenças , Endocitose/efeitos dos fármacos , Masculino , Camundongos Endogâmicos C57BL , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/patologia , Modelos Biológicos , Nanoestruturas/química , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Oxirredução , Fosfosserina/metabolismo , Multimerização Proteica , Espécies Reativas de Oxigênio/metabolismo , Rotenona , alfa-Sinucleína/metabolismo
12.
J Clin Microbiol ; 59(9): e0013221, 2021 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-34160275

RESUMO

The countries in the Indian subcontinent have reported a dramatic decline in visceral leishmaniasis (VL) cases. However, the presence of the parasite reservoir in the form of post-kala-azar dermal leishmaniasis (PKDL), a dermal sequel of VL, is a hurdle in attaining VL elimination. Presently employed clinical specimens for the diagnosis of PKDL include skin biopsy specimens and slit skin smears. In this study, the use of blood as a clinical specimen was investigated in different manifestations of PKDL in India. This is a bicentric study (National Institute of Pathology, Indian Council of Medical Research [ICMR], New Delhi, and Institute of Medical Sciences [IMS], Banaras Hindu University, Varanasi), with 215 participants (120 PKDL patients and 95 controls). Highly sensitive quantitative real-time PCR (Q-PCR) and field-deployable loop-mediated isothermal amplification (LAMP) were employed using blood samples for diagnosis. Promising sensitivities of 77.50% (95% confidence interval [CI], 69.24 to 84.05%) for Q-PCR and 70.83% (95% CI, 62.16 to 78.22%) for LAMP were obtained for the diagnosis of PKDL. Further, enhanced sensitivities of 83.33% (95% CI, 71.28 to 90.98%) and 77.78% (95% CI, 65.06 to 86.80%) for Q-PCR and LAMP, respectively, were recorded for the detection of macular cases. The study revealed an inverse correlation between the parasite load estimated in slit and blood samples, thereby favoring the use of blood for the diagnosis of the macular variant, which may be missed due to scant parasite loads in the slit. This study is the first to propose the promising potential of blood as a clinical specimen for accurate diagnosis of PKDL, which would aid in fast-tracking VL elimination.


Assuntos
Leishmania donovani , Leishmaniose Cutânea , Leishmaniose Visceral , Humanos , Índia , Leishmania donovani/genética , Leishmaniose Cutânea/diagnóstico , Leishmaniose Visceral/diagnóstico , Técnicas de Diagnóstico Molecular , Técnicas de Amplificação de Ácido Nucleico , Reação em Cadeia da Polimerase em Tempo Real
13.
Biogerontology ; 22(1): 35-47, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-32979155

RESUMO

Spermidine (SPD) is a natural polyamine present in all living organisms and is involved in the maintenance of cellular homeostasis by inducing autophagy in different model organisms. Its role as a caloric restriction mimetic (CRM) is still being investigated. We have undertaken this study to investigate whether SPD, acting as a CRM, can confer neuroprotection in D-galactose induced accelerated senescence model rat and naturally aged rats through modulation of autophagy and inflammation. Young male rats (4 months), D-gal induced (500 mg/kg b.w., subcutaneously) aging and naturally aged (22 months) male rats were supplemented with SPD (10 mg/kg b.w., orally) for 6 weeks. Standard protocols were employed to measure prooxidants, antioxidants, apoptotic cell death and electron transport chain complexes in brain tissues. Gene expression analysis with reverse transcriptase-polymerase chain reaction (RT-PCR) was performed to assess the expression of autophagy and inflammatory marker genes. Our data demonstrate that SPD significantly (p ≤ 0.05) decreased the level of pro-oxidants and increased the level of antioxidants. SPD supplementation also augmented the activities of electron transport chain complexes in aged brain mitochondria thus proving its antioxidant potential at the level of mitochondria. RT-PCR data revealed that SPD up-regulated the expression of autophagy genes (ATG-3, Beclin-1, ULK-1 and LC3B) and down-regulated the expression of the inflammatory gene (IL-6) in aging brain. Our results provide first line of evidence that SPD provides neuroprotection against aging-induced oxidative stress by regulating autophagy, antioxidants level and also reduces neuroinflammation. These results suggest that SPD may be beneficial for neuroprotection during aging and age-related disorders.


Assuntos
Galactose , Espermidina , Envelhecimento , Animais , Apoptose , Autofagia , Restrição Calórica , Masculino , Neuroproteção , Estresse Oxidativo , Ratos , Espermidina/farmacologia
14.
Soft Matter ; 17(31): 7260-7267, 2021 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-34337643

RESUMO

Fluorosurfactants have expanded the landscape of high-value biochemical assays in microfluidic droplets, but little is known about how the spatial geometries and polarity of the head group contribute to the performance of fluorosurfactants. To decouple this, we design, synthesize, and characterize two linear and two dendritic glycerol- or tris-based surfactants with a common perfluoropolyether tail. To reveal the influence of spatial geometry, we choose inter-droplet cargo transport as a stringent test case. Using surfactants with linear di- and triglycerol, we show that the inter-droplet cargo transport is minimal compared with their dendritic counterparts. When we encapsulated a less-leaky sodium fluorescent dye into the droplets, quantitatively, we find that the mean fluorescence intensity of the PFPE-dTG stabilized PBS-only droplets after 72 h was ∼3 times that of the signal detected in PBS-only droplets stabilized by PFPE-lTG. We also demonstrate that the post-functionalization of PFPE-lTG having a linear geometry and four hydroxy groups enables the 'from-Droplet' fishing of the biotin-streptavidin protein complex without the trade-off between fishing efficiency and droplet stability. Thus, our approach to design user-friendly surfactants reveals the aspects of spatial geometry and facile tunability of the polar head groups that have not been captured or exploited before.


Assuntos
Técnicas Analíticas Microfluídicas , Microfluídica , Corantes Fluorescentes , Tensoativos
15.
J Indian Assoc Pediatr Surg ; 26(5): 317-323, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34728917

RESUMO

AIMS: Congenital colonic stenosis (CCS) is an extremely rare cause of low-intestinal obstruction in neonates/child. We report our experience with seven cases of CCS presenting with low-intestinal obstruction and diagnosed intraoperatively and also propose an algorithm for its appropriate treatment for the adequate outcome. MATERIALS AND METHODS: It was a retrospective study of seven patients of CCS including two neonates (5-days and 15-days old), four infants (age range - 2-11 months), and one 24-month-old child admitted from 2014 to 2019. Information regarding the age of presentation, clinical presentation, physical findings, radiological and laboratory findings, details of surgery, and outcome was retrieved and analyzed. RESULTS: The male-to-female ratio was 5:2. Patients were initially diagnosed as cases of Hirschsprung's disease in five and ileal atresia in two. A final diagnosis of CCS was made during surgery and histopathological examination of resected stenotic segment. The segment involved was ascending colon in three, transverse colon in two, and sigmoid colon and junction of descending and sigmoid colon each in one patient. Resection of stenotic colonic segment and primary end-to-end anastomosis was performed in two, divided stoma after resection of the stenotic segment and secondary anastomosis in three, and proximal loop terminal ileostomy followed by resection of the stenotic colonic segment and ileocolic anastomosis after 10-12 weeks in two. CONCLUSIONS: CCS is a rare but possible cause of large-bowel obstruction, in neonatal, infant, and children particularly when associated with a history of chronic constipation since birth. It should be kept in mind as a differential diagnosis while managing a case of neonatal and pediatric intestinal obstruction, particularly low-bowel obstruction along with a history of chronic constipation. Treatment should be individualized for each patient based on clinical status and associated anomalies to give the best results with less morbidity.

16.
Haematologica ; 105(4): 971-986, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31371410

RESUMO

Leukemia stem cells contribute to drug-resistance and relapse in chronic myeloid leukemia (CML) and BCR-ABL1 inhibitor monotherapy fails to eliminate these cells, thereby necessitating alternate therapeutic strategies for patients CML. The peroxisome proliferator-activated receptor-γ (PPARγ) agonist pioglitazone downregulates signal transducer and activator of transcription 5 (STAT5) and in combination with imatinib induces complete molecular response in imatinib-refractory patients by eroding leukemia stem cells. Thiazolidinediones such as pioglitazone are, however, associated with severe side effects. To identify alternate therapeutic strategies for CML we screened Food and Drug Administration-approved drugs in K562 cells and identified the leprosy drug clofazimine as an inhibitor of viability of these cells. Here we show that clofazimine induced apoptosis of blood mononuclear cells derived from patients with CML, with a particularly robust effect in imatinib-resistant cells. Clofazimine also induced apoptosis of CD34+38- progenitors and quiescent CD34+ cells from CML patients but not of hematopoietic progenitor cells from healthy donors. Mechanistic evaluation revealed that clofazimine, via physical interaction with PPARγ, induced nuclear factor kB-p65 proteasomal degradation, which led to sequential myeloblastoma oncoprotein and peroxiredoxin 1 downregulation and concomitant induction of reactive oxygen species-mediated apoptosis. Clofazimine also suppressed STAT5 expression and consequently downregulated stem cell maintenance factors hypoxia-inducible factor-1α and -2α and Cbp/P300 interacting transactivator with Glu/Asp-rich carboxy-terminal domain 2 (CITED2). Combining imatinib with clofazimine caused a far superior synergy than that with pioglitazone, with clofazimine reducing the half maximal inhibitory concentration (IC50) of imatinib by >4 logs and remarkably eroding quiescent CD34+ cells. In a K562 xenograft study clofazimine and imatinib co-treatment showed more robust efficacy than the individual treatments. We propose clinical evaluation of clofazimine in imatinib-refractory CML.


Assuntos
Hanseníase , Leucemia Mielogênica Crônica BCR-ABL Positiva , Preparações Farmacêuticas , Apoptose , Clofazimina/farmacologia , Resistencia a Medicamentos Antineoplásicos , Proteínas de Fusão bcr-abl/genética , Humanos , Mesilato de Imatinib/farmacologia , Células K562 , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , PPAR gama
17.
Chemistry ; 26(30): 6919-6934, 2020 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-32027069

RESUMO

The syntheses of novel amphiphilic 5,5',6,6'-tetrachlorobenzimidacarbocyanine (TBC) dye derivatives with aminopropanediol head groups, which only differ in stereochemistry (chiral enantiomers, meso form and conformer), are reported. For the achiral meso form, a new synthetic route towards asymmetric cyanine dyes was established. All compounds form J aggregates in water, the optical properties of which were characterised by means of spectroscopic methods. The supramolecular structure of the aggregates is investigated by means of cryo-transmission electron microscopy, cryo-electron tomography and AFM, revealing extended sheet-like aggregates for chiral enantiomers and nanotubes for the mesomer, respectively, whereas the conformer forms predominately needle-like crystals. The experiments demonstrate that the aggregation behaviour of compounds can be controlled solely by head group stereochemistry, which in the case of enantiomers enables the formation of extended hydrogen-bond chains by the hydroxyl functionalities. In case of the achiral meso form, however, such chains turned out to be sterically excluded.

18.
Biochem Cell Biol ; 97(4): 480-487, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-30624963

RESUMO

An imbalanced redox status is a hallmark of the aging process. Caloric restriction mimetics (CRMs) are compounds that produce caloric restriction benefits at the molecular, cellular, and physiological level, translating into health-promoting effects. Fisetin is the least explored CRM, and its role in modulating oxidative stress during aging is not clearly known. This study investigated the antioxidative and protective potential of fisetin in a rat model of d-galactose (D-gal)-induced accelerated senescence, and in naturally aged rat erythrocytes. Young rats (4 months), aged D-gal-induced rats [24 months; 500 mg/kg body mass (b.m.); subcutaneous injection] and naturally aged D-gal-induced rats [24 months; 500 mg/kg b.m.; subcutaneous injection] were supplemented with fisetin (15 mg/kg b.m.; orally) for 6 weeks. The resulting data indicated that supplementation with fisetin suppresses aging-induced increases in the levels of reactive oxygen species, eryptosis, lipid peroxidation, and protein oxidation. Our data also show that fisetin significantly increases the levels of antioxidants and activates the plasma membrane redox system. Taken together, the findings show that a fisetin-rich diet could be an anti-aging intervention strategy.


Assuntos
Restrição Calórica , Senescência Celular/efeitos dos fármacos , Eritrócitos/efeitos dos fármacos , Flavonoides/farmacologia , Animais , Antioxidantes/metabolismo , Biomarcadores/metabolismo , Eritrócitos/metabolismo , Flavonoides/administração & dosagem , Flavonóis , Galactose/administração & dosagem , Galactose/farmacologia , Injeções Subcutâneas , Masculino , Ratos , Ratos Wistar
19.
Cell Mol Neurobiol ; 39(7): 901-915, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31190159

RESUMO

Parkinson's disease (PD) is an age-related, threatening neurodegenerative disorder with no reliable treatment till date. Identification of specific and reliable biomarker is a major challenge for disease diagnosis and designing effective therapeutic strategy against it. PD pathology at molecular level involves abnormal expression and function of several proteins, including alpha-synuclein. These proteins affect the normal functioning of neurons through various post-translational modifications and interaction with other cellular components. The role of protein anomalies during PD pathogenesis can be better understood by the application of proteomics approach. A number of proteomic studies conducted on brain tissue, blood, and cerebrospinal fluid of PD patients have identified a wide array of protein alterations underlying disease pathogenesis. However, these studies are limited by the types of brain regions or biofluids utilized in the research. For a complete understanding of PD mechanism and discovery of reliable protein biomarkers, it is essential to analyze the proteome of different PD-associated brain regions and easily accessible biofluids such as saliva and urine. The present review summarizes the major advances in the field of PD research in humans utilizing proteomic techniques. Moreover, potential samples for proteomic analysis and limitations associated with the analyses of different types of samples have also been discussed.


Assuntos
Doença de Parkinson/metabolismo , Proteômica , Líquidos Corporais/metabolismo , Encéfalo/metabolismo , Encéfalo/patologia , Humanos , Especificidade de Órgãos , Doença de Parkinson/sangue , Doença de Parkinson/líquido cefalorraquidiano
20.
J Indian Assoc Pediatr Surg ; 24(2): 120-123, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31105398

RESUMO

BACKGROUND: Meconium ileus (MI) is defined as an intestinal obstruction caused by the impaction of inspissated meconium in the terminal ileum. In this study, we have evaluated the nonoperative management of patients of simple MI without fluoroscopic support -an important requisite of the Noblett's criteria. Besides this, surgical management in cases of failed conservative management and complicated MI was also assessed. MATERIALS AND METHODS: This was a retrospective observational study. Various clinical and radiological parameters were evaluated. Conservative management included the use of water-soluble contrast diatrizoate meglumine and diatrizoate sodium. In case of nonpassage of meconium in 24 h from first intervention, exploratory laparotomy with ileostomy was performed. All complicated MI underwent exploratory laparotomy with creation of stoma as and when needed. RESULTS: The duration of this study was 6½ years. Twenty-five neonates of MI were admitted. Of these, 22 had simple MI and remaining three had complicated MI. Eighteen neonates responded to the conservative management. In four neonates, who did not respond, exploratory laparotomy was performed. All three neonates having complicated MI underwent exploratory laparotomy. One patient expired in follow-up. CONCLUSION: MI is an important neonatal emergency, which needed immediate attention of a pediatric surgeon. Proper evaluation of the patient, careful application of principals of conservative management, and timely surgical intervention may fetch satisfactory results.

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